Document:

Exhibit 10.28

	
                                        REVOLVING LINE OF CREDIT AGREEMENT

                                                  by and between

                                                   BIOTIME, INC.

                                                   as “Borrower”

                                                        and

                                                ALFRED D. KINGSLEY

                                                    as “Lender”

                                            Dated as of March 27, 2001

                                                 TABLE OF CONTENTS

1.       General Definitions......................................................................................1

2.       Draws and Disbursements..................................................................................2

3.       Terms of Payment.........................................................................................4

4.       Warrant..................................................................................................5

5.       Events of Default........................................................................................5

6.       Remedies On Default......................................................................................6

7.       Representations and Warranties of Borrower...............................................................6

8.       Affirmative Covenants....................................................................................8

9.       Fees and Charges of Attorneys and Others.................................................................9

10.      Maximum Permitted Interest..............................................................................10

11.      Governing Law...........................................................................................10

12.      Successors and Assigns..................................................................................10

13.      Entire Agreement; Amendment.............................................................................10

14.      Survival................................................................................................10

15.      Notices.................................................................................................10

16.      Delays and Omissions....................................................................................11

17.      Rules of Construction...................................................................................11

18.      Severability............................................................................................12

19.      Counterparts............................................................................................12

	
                                                        i

REVOLVING LINE OF CREDIT AGREEMENT

     This Revolving Line of Credit Agreement (“Credit Agreement”) is made and entered into as of
March 27, 2001, by and between Alfred D. Kingsley (“Lender”), and BioTime, Inc., a California
corporation (“Borrower”).

                                                      RECITALS

Borrower has requested a
credit facility consisting of a revolving line of credit, and Lender is willing
to make the requested credit facility to Borrower, but only upon the terms, and
subject to the conditions, contained herein. 

                                                      AGREEMENT

Now, therefore, in consideration of the premises and the mutual covenants hereinafter contained,
the parties hereto agree as follows:

              1.1        General Definitions.  The following words shall have the following meanings:

                                 1.1.1     “Business Day” means any day that is not a Saturday, a Sunday, or a day
on which banks are required, or permitted, to be closed in the State of New York.

                                 1.1.2     “Credit Facility” means the right of Borrower to borrow up to $1,000,000
from Lender under the terms and conditions of this Credit Agreement and the Note.

                                 1.1.3    “Debtor Relief Law”  means the Bankruptcy Code of the United States of
America, as amended, or any other applicable liquidation, conservatorship, bankruptcy,
moratorium, rearrangement, receivership, insolvency, reorganization, or similar debtor relief law
affecting the rights of creditors generally.

                                 1.1.4     “Event of Default” or “Events of Default” means any of the events
specified in Section 5, 2.

                                 1.1.5     “Loan” means the loans made by Lender to Borrower pursuant to this Credit
Agreement, and evidenced by the Note.

                                 1.1.6     “Loan Documents”  means this Credit Agreement, the Note, the Warrant
Agreement, and all other agreements, instruments, and documents in favor of Lender, now or
hereafter executed by or on behalf of Borrower and delivered to Lender in connection with this
Credit Agreement or in connection with any of the transactions contemplated hereby.

                                                        1

                                 1.1.7     “Maturity Date”  means the earlier of (i) March 31, 2002, and (ii) such date
on which Borrower shall have received an aggregate of $2,000,000 through (A) the sale of capital
stock, (B) the collection
of license fees, signing fees, milestone fees, or similar fees under
Borrower’s Exclusive License Agreement with Abbott Laboratories, Exclusive
License Agreement with Horus, B.V., or under any other present or future
agreement pursuant to which Borrower grants one or more licenses to use
Borrower’s patents or technology, (C) funds borrowed from other lenders, or
(D) any combination of sources under clauses (A) through (C).

                                 1.1.8     “Note” means the promissory note, of even date, in the form attached as
EXHIBIT A, evidencing the Loan to be executed concurrently with this Credit Agreement.

                                 1.1.9     “Warrant” means the stock purchase warrant issued under the Warrant
Agreement attached as EXHIBIT B, entitling the holder thereof to purchase common shares of the
Borrower.

              1.2        Draws and Disbursements.

                                 1.2.1     Maximum Loan Amount.  On the terms and conditions set forth in this
Credit Agreement, Lender shall make available to Borrower the Credit Facility, as a revolving line
of credit in a principal amount not to exceed at any one time One Million Dollars ($1,000,000),
less all amounts of principal prepaid or required to be prepaid under Section 3.2.1 of this Credit
Agreement (the “Maximum Loan Amount”).

                                 1.2.2     Draw Period.  Borrower may request from Lender advances of funds
(“Draws”) under the Credit Facility from the date of this Agreement until March 1, 2002 (the
“Draw Period”).  As amounts drawn by Borrower hereunder are repaid, they may be reborrowed
subject to the terms and conditions of this Credit Agreement; provided, that at no time shall the
aggregate principal amount of Loans outstanding under this Credit Agreement exceed the
Maximum Loan Amount.  The Draw Period may be terminated by Borrower at any time by
written notice to Lender.  Subject to the terms and conditions of this Credit Agreement, and
provided that no Event of Default has occurred, Lender shall make advances to Borrower upon
request as provided in this Section 2.  Upon the occurrence of an Event of, one of Lender’s
remedies includes Lender’s right to terminate the Draw Period and Borrower’s right to make
Draws under this Credit Agreement.

                                 1.2.3     Increments.  Draws must be in increments of not less than One Hundred
Thousand Dollars ($100,000), or the remaining amount available under the Credit Facility,
whichever is less.

                                 1.2.4     Use of Funds.  All funds borrowed under this Credit Agreement will be
used as working capital to pay Borrower expenses arising in the ordinary course of business.

              1.2.5      Disbursement Procedures.

                                                         2

                         2.5.1     Borrower hereby appoints its Chief Executive Officer, President, and
Chief Financial Officer as
the officers authorized to make Draws under this Credit Agreement during the
Draw Period. Any one of such officers (the “Authorized Officers”) is
authorized to make Draws. Lender, at its sole option, may require that all
requests for Loan funds be in writing, signed by an Authorized Officer, in a
form acceptable to Lender. Facsimile documents may be accepted by Lender as
originals. Any Draw by an Authorized Officer shall constitute an ongoing
representation and warranty by Borrower that at the time of request for or
payment of any Draw no Event of Default has occurred.

                        2.5.2     Draws shall be paid according to the Authorized Officer’s
instructions, except that
checks representing Loan funds shall always be made payable to Borrower, and
wire transfers shall only be permitted if Borrower has authorized payment into
the account into which the funds are to be deposited. The appointment of the
above-named Authorized Officer(s) shall remain in full force and effect until
written notice of revocation of appointment signed by the Chief Executive
Officer or Chief Financial Officer of Borrower has been received by Lender.

                       2.5.3     Lender shall advance Loan funds available under the Credit Facility
in accordance with
Borrower’s Draws within four (4) Business Days after the receipt of the
Draw. 

                      2.5.4     Each Draw shall be accompanied by the certificates required by
Section 2.6.

                      2.5.5     Borrower shall indemnify and hold Lender harmless from loss or
liability of any kind
arising from or related to any action or inaction taken by Lender in good faith
in reliance upon instructions received from any Authorized Officer.

                                 1.2.6      Conditions Precedent.  The following conditions must be satisfied before
Lender shall be obligated to disburse Loan funds to Borrower pursuant to a Draw:

                      2.6.1     Due execution.  Lender shall have received duly originals of this
Credit Agreement and all other Loan Documents.

                       2.6.2     Approvals.  Lender shall have received evidence satisfactory to it
that all consents and
approvals which are necessary for, or required as a condition of, the validity
and enforceability of this Credit Agreement and all other Loan Documents have
been obtained and are in full force and effect.

                      2.6.3     Representations and Warranties Correct.  All of Borrower’s
representations and
warranties contained in this Credit Agreement and in any other Loan Document
shall be true and correct in all material respects on the date the Loan funds
are disbursed, and Borrower shall have delivered to Lender a certificate executed by an Authorized
Officer to such effect.

                          2.6.4     No Event of Default.  No Event of Default shall have occurred, and
Borrower shall have delivered to Lender a certificate executed by an Authorized Officer to such
effect.

                                                         3

                       2.6.5     Independent Verification.  Borrower must provide for Lender’s
review and acceptance such
documentation as may be required by Lender to ensure Borrower is in compliance
with the terms and conditions of this Credit Agreement, including, without
limitation, resolutions of Borrower’s board of directors or a duly
constituted and authorized committee thereof, certified by the secretary or an
assistant secretary of the corporation, authorizing the execution and delivery
of this Agreement and the other Loan Documents and performance of
Borrower’s obligations hereunder and thereunder. 

                        2.6.6     Warrant.  Prior to the initial Draw under this Credit Agreement,
Borrower must have executed
the Warrant Agreement and issued the Warrant to Lender.

                         2.6.7     Closing Costs.  Borrower must have paid all attorneys’ fees incurred
by Lender in connection the preparation,
execution, and delivery of the Loan Documents, and all reports and notices
required to be filed by Lender or its affiliates under the Securities Exchange
Act of 1934, as amended, in connection with this Agreement and Lender’s
receipt of the Warrant. 

               1.3        Terms of Payment.

                      1.3.1     Interest.  Interest shall accrue and be payable at the rate of 10% per annum
on the outstanding principal balance of the Loan.  Interest shall accrue from the date of each
disbursement of principal pursuant to a Draw.  Accrued interest shall be paid with principal on
the Maturity Date.  Interest will be charged on that part of outstanding principal of the Loan which
has not been paid and shall be calculated on the basis of a 360-day year and a 30-day month.

                         1.3.2     Payment of Principal.  The outstanding principal balance of the Loan,
together with accrued interest, shall be paid in full on the Maturity Date.

                           3.2.1     Mandatory Prepayment of Principal.  In the event that Borrower
receives, in the aggregate,
an amount of funds in excess of $1,000,000 but less than $2,000,000 from (A) the
sale of capital stock, (B) the collection of license fees, signing fees,
milestone fees, or similar fees under Borrower’s Exclusive License
Agreement with Abbott Laboratories, Exclusive License Agreement with Horus,
B.V., or under any other present or future agreement pursuant to which Borrower
grants one or more licenses to use Borrower’s patents or technology, (C)
funds borrowed from other lenders, or (D) any combination of sources under
clauses (A) through (C), Borrower shall use the funds in excess of $1,000,000 to
prepay principal, plus
accrued interest, within
two business days after such funds are received by Borrower, and the amount of
principal so prepaid shall reduce the Maximum Loan Amount.

                         3.2.2     Optional Prepayment of Principal.  Borrower may prepay
principal, with accrued
interest, at any time and the amount of principal so prepaid shall be available
for further Draws by Borrower during the Draw Period to the extent that the
prepayment of principal was not required under Section 3.2.1.  
    

4

                   1.3.3     Default Interest Rate; Late Payment Charge.  In the event that any
payment of principal or interest is not paid within five (5) days from on the date on which the
same is due and payable, such payment shall continue as an obligation of the Borrower, and
interest thereon from the due date of such payment and interest on the entire unpaid balance of the
Loan shall accrue until paid in full at the lesser of (i) fifteen percent (15%) per annum, or (ii) the
highest interest rate permitted under applicable law (the “Default Rate”).  From and after the
Maturity Date or upon acceleration of the Note, the entire unpaid principal balance of the Loan
with all unpaid interest accrued thereon, and any and all other fees and charges then due at such
maturity, shall bear interest at the Default Rate.

                1.3.4     Date of Payment.  If the date on which a payment of principal or interest
on the Loan is due is a day other than a Business Day, then payment of such principal or interest
need not be made on such date but may be made on the next succeeding Business Day.

                 1.3.5     Application of Payments.  All payments shall be applied first to costs of
collection, next to late charges or other sums owing Lender, next to accrued interest, and then to
principal, or in such other order or proportion as Lender, in its sole discretion, may determine.

                1.3.6     Currency.  All payments shall be made in United States Dollars.

     1.4    Warrant. As consideration for Lender making Credit Faculty available to
Borrower, Borrower will issue and deliver Lender a Warrant to purchase fifty
thousand (50,000) common shares, no par value of Borrower. The exercise price of
the Warrant will be $8.31. 

     1.5   Events of Default. The following shall constitute Events of Default: (a)
the default of Borrower in the payment of any interest or principal due under
this Credit Agreement or the Note; (b) the failure of Borrower to perform or
observe any other term or provision of, or covenant, agreement, or obligation
under, this Credit Agreement or any other Loan Document; (c) any act, omission,
or other event that constitutes an “Event of Default” under the Note;
(d) any representation or warranty of Borrower contained in this Credit
Agreement or in any other Loan Document, or in any certificate delivered by
Borrower pursuant to this Credit Agreement or any other Loan Document, is false
or misleading in any material respect when made or given; (e) Borrower becoming
the subject of any order for relief in a proceeding under any Debtor Relief Law;
(f) Borrower making an assignment for the benefit of creditors; (g) Borrower
applying for or consenting to the appointment of any receiver, trustee,
custodian, conservator, liquidator,
rehabilitator, or similar
officer for it or for all or any part of its property or assets; (h) the
appointment of any receiver, trustee, custodian, conservator, liquidator,
rehabilitator, or similar officer for Borrower, or for all or any part of the
property or assets of Borrower, without the application or consent Borrower if
such appointment continues undischarged or
unstayed for sixty (60) calendar
days; (i) Borrower instituting or consenting to any proceeding under any Debtor
Relief Law with respect to Borrower, or all or any part of its property or
assets, or the institution of any similar case or proceeding without the consent
of Borrower, if such case or proceeding continues undismissed or unstayed for
sixty (60) calendar days; (j) the dissolution or liquidation of Borrower, or the
winding-up of the business or affairs of Borrower; (k) the taking of any action
by Borrower to initiate any of the actions described in clauses (f) through (j)
of this paragraph; (l) the issuance or levy of any judgment, writ, warrant of
attachment or execution or similar process against all or any material part of
the property or assets of Borrower if such process is not released, vacated or
fully bonded within sixty (60) calendar days after its issue or levy; or (m) any
breach or default by Borrower under its Exclusive License Agreement with Abbott
Laboratories, its Exclusive License Agreement with Horus, B.V., or under any
loan agreement, promissory note, or other instrument evidencing indebtedness
payable to a third party.

                                                 5

     1.6   Remedies On Default. Upon the occurrence of an Event of Default, at
Lender’s option, all unpaid principal and accrued interest, and all other
amounts payable under this Credit Facility and any other Loan Document shall
become immediately due and payable without presentment, demand, notice of
non-payment, protest, or notice of non-payment. Lender also shall have all other
rights, powers, and remedies available under this Credit Agreement and the Note
or any other Loan Document, or accorded by law or at equity. All rights, powers,
and remedies of Lender may be exercised at any time by Lender and from time to
time after the occurrence of an Event of Default. All rights, powers, and
remedies of Lender in connection with this Credit Agreement and the Note and any
Loan Document are cumulative and not exclusive and shall be in addition to any
other rights, powers, or remedies provided by law or equity. 

               1.7     Representations and Warranties of Borrower.  Borrower represents and warrants
to Lender the following:

                    1.7.1    Organization; Capitalization.  Borrower is a corporation duly organized,
validly existing and in good standing under the laws of the state of California and has all requisite
corporate power and authority to own its property and to carry on its business as now being
conducted.

                    1.7.2     Authority; Enforceability.  Borrower has the power and authority to
execute and deliver this Credit Agreement and each of the other Loan Documents, and to perform
all of Borrower’s obligations under this Credit Agreement and the other Loan Documents.  This
Credit Agreement and each of the other Loan Agreements is the valid and binding agreement and
obligation of Borrower, enforceable in accordance with its respective terms, except to the extent
limited by any bankruptcy, insolvency, or similar law affecting the rights of creditors generally.
There are no corporate, contractual, statutory, regulatory,
judicial, or other restrictions of any kind upon the power and
authority of Borrower to execute and deliver this Credit Agreement or any other
Loan Document, and to consummate the transactions contemplated by this Credit
Agreement and the other Loan Documents, including, without limitation: (a) the
payment of all principal and interest that may become due on the Loan; and (b)
the issuance of the Warrant and common shares issuable upon the exercise of the
Warrant. No action, approval or consent by, or notice to or filing with, any
federal, state, municipal or other governmental department, commission, agency,
regulatory authority, or court is necessary to make this Credit Agreement or the
other Loan Documents the valid agreements binding upon Borrower in accordance
with their respective terms, or to consummate the transactions contemplated by
this Credit Agreement and the other Loan Documents.

                 1.7.3     No Conflict.  The execution and delivery of this Credit Agreement and the
other Loan Documents, and the consummation of the transactions contemplated by this Credit
Agreement and the other Loan Documents, do not and will not (a) violate any provisions of (i) any
rule, regulation, statute, or law, or (ii) the terms of any order, writ or decree of any court or
judicial or regulatory authority or body, or (iii) the Articles of Incorporation or Bylaws of
Borrower, and (b) conflict with or result in a breach of any condition or provision or constitute
a default under or pursuant to the terms of any contract, mortgage, lien, lease, agreement,
debenture or instrument to which Borrower or any Subsidiary is a party, or which is or purports
to be binding upon Borrower, any Subsidiary, or upon any of their respective properties, and (c)
result in the creation or imposition of any lien, charge or encumbrance upon any of the assets or
properties of Borrower or any Subsidiary.

                                                     6

                 1.7.4     Warrant and Warrant Shares.  The Warrant, when issued pursuant to this
Credit Agreement, will be a duly authorized, valid, and binding obligation of Borrower,
enforceable in accordance with its terms.  When issued and sold upon the exercise of the Warrant
in accordance with its terms, the common shares of the Borrower will be validly issued and
outstanding, fully paid and non-assessable.

                 1.7.5     Accuracy of Information.  Borrower has delivered to Lender a copy of
Borrower’s financial statements for the year ended on December 31, 2000, as will be included in
its Form 10-K for such fiscal year, its annual report on Form 10-K for the fiscal year ended
December 31, 1999, and quarterly report on Form 10-Q for the fiscal quarter and nine months
ended September 30, 2000, and Form 8-K (the “Disclosure Documents”).  The financial
statements contained in the Disclosure Documents were prepared in accordance with generally
accepted accounting principles, consistently applied, and accurately reflect the financial condition
and results of operations of Borrower at and as of the dates reported.  All financial information
and other information contained in the Disclosure Documents was true and correct in all material
respects when such reports were filed under the Securities Exchange Act of 1934, as amended (the
“Exchange Act”), and in the case of the financial statements for the fiscal year ended December
31, 2000, is true and correct in all material respects on the date of this Credit Agreement, except
for changes arising from operations in the ordinary course of business since December 31, 2000.

                   1.7.6     Taxes.  Borrower has filed when due all federal, state and local income tax
returns and has filed when due all other returns with respect to taxes which are required to be filed
with the Internal Revenue Service and the appropriate authorities of the jurisdictions where
business is transacted by them.  All items and entries provided for or reflected in such returns are
correct and are made on a proper basis.  All amounts, if any, required to be paid, as shown on
such returns, have been paid.  None of such tax returns has been audited.  There are no suits,
actions, claims, or investigations, inquiries or proceedings now pending against Borrower in
respect of taxes, governmental charges or assessments, nor are there any matters under discussion
with any governmental authority relating to taxes, governmental charges or assessments asserted
by any such authority.

                   1.7.7     Litigation.  Except as disclosed in the Disclosure Documents, there are no
lawsuits, arbitration proceedings, administrative proceedings, actions or claims pending or
threatened against Borrower.  No fine, penalty or other sanction has been imposed by any federal,
state, local or municipal court, judicial, administrative or regulatory body or authority against
Borrower.  There is no outstanding order, writ, injunction or degree of any court, administrative
agency or governmental body or arbitration tribunal against or affecting Borrower or any of its
respective properties, assets, business or prospects.

     1.8   Affirmative Covenants. During the Draw Period, and until such time as the
entire principal balance and accrued interest on the Loan, and all other amounts
payable by Borrower under this Credit Agreement or any other Loan Document have
been paid in full, Borrower shall comply with the following covenants and
agreements: 

                  1.8.1     Furnish Information.  Borrower will, at Lender’s request, furnish
information to Lender relating to Borrower’s business and financial affairs and permit Lender to
examine Borrower’s books and records.

                                                       7

                  1.8.2     Other Documents.  Borrower will execute all other documents as Lender
may reasonably require in connection with this Credit Agreement and Note in order to perfect its
lien or security interest in any of the collateral for the loan, or otherwise to give effect to the terms
and conditions of the loan or guaranty for the loan.

                 1.8.3     Comply with Terms and Conditions.  Borrower will comply with all terms
and conditions of all other Loan Documents.

                  1.8.4     Financial Reports.  Borrower will file with the Securities and Exchange
Commission, when due, all quarterly reports, annual reports, current reports, and other documents
required pursuant to the Exchange Act and within 5 days of the date such reports and other
documents are so required to be filed, to mail to Lender a copy of such reports.

                    1.8.5     Limitation on Dividends and Other Distributions by Borrower.
Borrower shall not declare or pay any dividend or other distribution of cash, other property, or
evidences of indebtedness, on account of or with respect to any shares of capital stock.

                  1.8.6     Insurance.  Borrower will, and will cause its Subsidiaries, to maintain
insurance with responsible carriers against such risks and in such amounts as is customarily carried
by similar businesses with such deductible as are customarily carried by similar businesses of
similar size, including, without limitation, property and casualty loss, workers’ compensation and
interruption of business insurance.

      1.9    Fees and Charges of Attorneys and Others. In the event that Lender
employs attorneys, accountants, appraisers, consultants, or other professional
assistance, including the services of any such person who is a direct employee
of Lender, in connection with any of the following, then, the reasonable amount
of costs, expenses, and fees incurred by Lender shall be payable on demand.
Lender may, at its option, add the amount of such costs, expenses, and
reasonable fees to the principal amount of the Loan. Lender thereafter may
charge interest on such amount at the interest rate then applicable to the
principal. Costs, expenses, and reasonable fees of professionals covered by this
provision include such charges for the following: 

                     1.9.1     The preparation, modification, or renewal of this Credit Agreement and the
Note, or any other documentation incident to the loan transaction;

                     1.9.2     Any litigation, dispute, proceeding or action, whether instituted by Lender,
Borrower, or any other person, relating to the Note, including representation of Lender in any
bankruptcy, insolvency, or reorganization case or proceeding instituted by or against Borrower,
and any attempt by Lender to enforce any rights against Borrower;

                 1.9.3     In the event of any controversy, claim, or dispute relating to the Note or this
Agreement, including but not limited to any action to construe or enforce the terms of the loan
obligations, the prevailing party shall be entitled to recover its reasonable costs, expenses, and
reasonable attorney fees;

                                                    8

                1.9.4     In the event of bankruptcy or insolvency proceedings (whether state or
federal) instituted by or against Borrower or involving the Borrower or Property of the Borrower,
the Lender may recover all costs, expenses, and reasonable attorney fees incurred to protect or
defend Lender’s rights under the Note, and other documents underlying the loan transactions
whether such costs, expenses, and attorney fees be contractual or bankruptcy related, including
costs, expenses, and attorney fees for meetings, sessions, matters, proceedings and litigation
involving issues solely distinct to federal bankruptcy law, rules and proceedings as well as other
federal and state litigation and proceedings;

                1.9.5     The inspection, verification, protection, collection, processing, sale,
liquidation, or disposition of security given for the Note;

                  1.9.6     The preparation and filing of all reports required to be filed by Lender under
the Exchange Act during the term of this Credit Agreement in connection with the ownership,
acquisition, or disposition of the Warrant, common shares, or other equity securities issued by
Borrower.

     1.10    Maximum Permitted Interest. No provision of this Credit Agreement or any
other Loan Document, or any transaction related thereto, shall be construed or
so operate as to require the Borrower to pay interest at a greater rate than the
maximum allowed by applicable state or federal law. Should any interest or other
charges paid or payable by the Borrower in connection with the Loan result in
the computation or earning of interest in excess of the maximum allowed by
applicable state or federal law, then any and all such excess shall be and the
same is hereby waived by Lender, and any and all such excess paid shall be
credited automatically against and in reduction of the outstanding principal
balance due of the Loan, and the portion of said excess which exceeds such
principal balance shall be paid by Lender to the Borrower. 

      1.11       Governing Law. This Credit Agreement shall be construed and governed in all
respects by the laws of the State of California.

     1.12    Successors and Assigns. The provisions of this Credit Agreement shall
inure to the benefit of, and be binding upon, the respective successors,
assigns, heirs, executors and administrators of Borrower and Lender.

     1.13    Entire Agreement; Amendment. This Credit Agreement and the other Loan
Documents constitute the full and entire understanding and agreement among the
parties with regard to the subject matter thereof. This Credit Agreement and any
term of this Credit Agreement may be amended, waived, discharged or terminated
only by a written instrument signed by the party to be charged.

     1.14    Survival. Borrower’s representations and warranties contained in
this Credit Agreement shall survive the funding of each Draw and any
investigation made by any party until the Maturity Date.

                                                      9

     1.15    Notices. All notices and other communications required or permitted to be
given pursuant to this Agreement shall be in writing and shall be deemed given
four (4) days after being deposited in the United States mail, certified postage
prepaid, return receipt requested, or when delivered by hand, by messenger or
express air freight service, in any case addressed as follows:

         To Lender:                         Alfred D. Kingsley
                                            277 Park Avenue
                                            New York, NY 10017
                                            FAX:  (212) 350-5253

         To Borrower:                       BioTime, Inc.
                                            935 Pardee Street
                                            Berkeley, California 94710
                                            Attention: Paul Segall, Chief Executive Officer
                                            FAX:  (510) 845-7914

                                            with a copy to:
                                            Richard S. Soroko, Esq.
                                            Lippenberger, Thompson, Welch, Soroko & Gilbert LLP
                                            201 Tamal Vista, Blvd.
                                            Corte Madera, California  94925

	
Any party may change its
address for the purpose of this Section 15 by giving notice to each other party
in accordance with this Section 15. 

     1.16    Delays and Omissions. No delay or omission to exercise any right, power,
or remedy accruing to Lender, upon any breach or default of Borrower under this
Credit Agreement or any other Loan Document, shall impair any such right, power,
or remedy of Lender, nor shall it be construed to be a waiver of, or an
acquiescence in, any such breach or default or any similar breach or default
thereafter occurring; nor shall any waiver of any single breach or default be
deemed a waiver of any other breach or default theretofore or thereafter
occurring. Any waiver, permit, consent, or approval of any kind or character on
the part of Lender of any breach or default by Borrower under this Credit
Agreement or any other Loan Document, or any waiver of any provisions or
conditions of this Credit Agreement or any other Loan Document by Lender, must
be made in writing, and shall be effective only to the extent specifically set
forth in such writing. All remedies either under this Agreement or by law and
otherwise afforded to any party shall be cumulative and not alternative.

               1.17       Rules of Construction.

                  1.17.1             Titles and Subtitles.  The titles or headings of the Sections and paragraphs
of this Credit Agreement are for convenience of reference only and are not to be considered in
construing this Credit Agreement.

 10

                    1.17.2             Singular; Plural.  Whenever appropriate in this Agreement, terms in the
singular form shall include the plural (and vice versa) and any gender form shall include all others.

                  1.17.3           Section Headings.  Section headings are for the convenience of the parties
and do not form a part of this Agreement.

                  1.17.4          Sections and Other References.  References in this Agreement to sections,
paragraphs, and exhibits are references to articles, sections, and paragraphs in this Agreement and
schedules and exhibits attached to this Agreement unless specified otherwise.

     1.18   Severability. If one or more provisions of this Credit Agreement are held
to be unenforceable under applicable law, each such unenforceable provision
shall be excluded from this Credit Agreement and the balance of this Credit
Agreement shall be interpreted as if each such unenforceable provision were so
excluded, and the balance of this Credit Agreement as so interpreted shall be
enforceable in accordance with its terms. 

          1.19       Counterparts.  This Credit Agreement may be executed in any number of
counterparts, each of which shall be an original, but all of which together shall constitute one
instrument.

                                                        11

              IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of the date
first above written.

BORROWER:                           BIOTIME, INC.

                                    By          /s/ Paul E. Segall
                                         -------------------------------------------

                                    Title     Chief Executive Officer
                                         -------------------------------------------

                                    By         /s/ Victoria Bellport
                                         -------------------------------------------

                                    Title     Chief Financial Officer
                                         -------------------------------------------

LENDER:                                 /s/ Alfred D. Kingsley
                                    ------------------------------------------------
                                            Alfred D. Kingsley

	
                                                       12

                                                                                                          EXHIBIT A

                                                REVOLVING CREDIT NOTE

$1,000,000                                                                                                         March 27, 2001

	

     FOR
VALUE RECEIVED, the undersigned, BioTime, Inc., a California corporation
(Borrower”) hereby promises to pay to the order of Alfred D. Kingsley
(“Lender”) the principal sum of ONE MILLION DOLLARS ($1,000,000) or
such lesser amount as may from time to time be outstanding as the Loan pursuant
to that certain Revolving Line of Credit Agreement, of even date, between
Borrower and Lender (the “Credit Agreement”), together with interest
on the unpaid balance of the Loan at the rate or rates hereinafter set forth.
This Revolving Credit Note is the Note described in the Credit Agreement. All
capitalized terms not otherwise defined in this Note shall have the meanings
defined in the Credit Agreement. 

1.      1.1   Terms of Payment.

              1.1.1     Interest Rate.  Interest shall accrue and be payable at the rate of 10% per
annum on the outstanding principal balance of the Loan. Interest shall accrue from the date of each
disbursement of principal pursuant to a Draw.  Accrued interest shall be paid with principal.
Interest will be charged on that part of outstanding principal of the Loan which has not been paid
and shall be calculated on the basis of a 360-day year and a 30-day month.

                1.1.2     Payments of Principal.  The outstanding principal balance of the Loan,
together with accrued interest, shall be paid in full on the Maturity Date. “Maturity Date” means
the earlier of (i) March 31, 2002, and (ii) such date on which Borrower shall have received an
aggregate of $2,000,000 through (A) the sale of capital stock, (B) the collection of license fees,
signing fees, milestone fees, or similar fees under Borrower’s Exclusive License Agreement with
Abbott Laboratories, Exclusive License Agreement with Horus, B.V., or under any other present
or future agreement pursuant to which Borrower grants one or more licenses to use Borrower’s
patents or technology, (C) funds borrowed from other lenders, or (D) any combination of sources
under clauses (A) through (C).

               1.1.3     Mandatory Prepayment of Principal.  In the event that Borrower receives,
in the aggregate, an amount of funds in excess of $1,000,000 but less than $2,000,000 from
sources described in clauses (A) through (C) of paragraph (b) of this Section 1, Borrower shall use
the funds in excess of $1,000,000 to prepay principal, plus accrued interest, within two business
days after such funds are received by Borrower, and the amount of principal so prepaid shall not
be available for further Draws by Borrower during the Draw Period.

              1.1.4     Optional Prepayment of Principal.  Borrower may prepay principal, with
accrued interest, at any time and the amount of principal so prepaid shall be available for further
Draws by Borrower during the
Draw Period to the extent that the prepayment of principal was not required
under paragraph (c) of this Section 1.

                                                         1

              1.1.5     Default Interest Rate.  In the event that any payment of principal or interest
is not paid within five (5) days from on the date on which the same is due and payable, such
payment shall continue as an obligation of the Borrower, and interest thereon from the due date
of such payment and interest on the entire unpaid balance of the Loan shall accrue until paid in full
at the lesser of (i) fifteen percent (15%) per annum, or (ii) the highest interest rate permitted under
applicable law (the “Default Rate”).  From and after the Maturity Date or upon acceleration of the
Note, the entire unpaid principal balance of the Loan with all unpaid interest accrued thereon, and
any and all other fees and charges then due at such maturity, shall bear interest at the Default Rate.

                1.1.6   Date of Payment.  If the date on which a payment of principal or interest
on the Loan is due is a day other than a Business Day, then payment of such principal or interest
need not be made on such date but may be made on the next succeeding Business Day.

              1.1.7     Application of Payments.  All payments shall be applied first to costs of
collection, next to late charges or other sums owing Lender, next to accrued interest, and then to
principal, or in such other order or proportion as Lender, in its sole discretion, may determine.

              1.1.8     Currency.  All payments shall be made in United States Dollars.

     1.2   Events of Default. The following shall constitute Events of Default:
1.2.1 the default of Borrower in the payment of any interest or principal due
under this Note or the Credit Agreement; 1.2.2 the failure of Borrower to
perform or observe any other term or provision of this Note, or any term,
provision, covenant, or agreement in the Credit Agreement or any other Loan
Document; 1.2.3 any act, omission, or other event that constitutes an
“Event of Default” under the Credit Agreement; 1.2.4 any
representation or warranty of Borrower contained in the Credit Agreement or in
any other Loan Document, or in any certificate delivered by Borrower pursuant to
the Credit Agreement or any other Loan Document, is false or misleading in any
material respect when made or given; 1.2.5 Borrower becoming the subject of any
order for relief in a proceeding under any Debtor Relief Law (as defined below);
1.2.6 Borrower making an assignment for the benefit of creditors; 1.2.7 Borrower
applying for or consenting to the appointment of any receiver, trustee,
custodian, conservator, liquidator, rehabilitator, or similar officer for it or
for all or any part of its property or assets; 1.2.8 the appointment of any
receiver, trustee, custodian, conservator, liquidator, rehabilitator, or similar
officer for Borrower, or for all or any part of the property or assets of
Borrower, without the application or consent Borrower, if such appointment
continues undischarged or unstayed for sixty (60) calendar days; 1.2.9 Borrower
instituting or consenting to any proceeding under any Debtor Relief Law with
respect to Borrower or all or any part of its property or assets, or the
institution of any similar case or proceeding without the consent of Borrower,
if such case or proceeding continues undismissed or unstayed for sixty (60)
calendar days; 1.2.10 the dissolution or liquidation of Borrower, or the
winding-up of the business or affairs of Borrower; 1.2.11 the taking of any
action by Borrower to initiate any of the actions described in clauses (f)
through (j) of this paragraph; 1.2.12 the issuance or levy of any judgment,
writ, warrant of attachment or execution or similar process
against all or any material
part of the property or assets of Borrower if such process is not released,
vacated or fully bonded within sixty (60) calendar days after its issue or levy;
or (m) any breach or default by Borrower under its Exclusive License Agreement
with Abbott Laboratories, its Exclusive License Agreement with Horus, B.V., or
under any loan agreement, promissory note, or other instrument evidencing
indebtedness payable to a third party. As used in this Note, the term
“Debtor Relief Law” means the Bankruptcy Code of the United States of
America, as amended, or any other applicable liquidation, conservatorship,
bankruptcy, moratorium, rearrangement, receivership, insolvency, reorganization,
or similar debtor relief law affecting the rights of creditors generally.

                                                      2

     1.3   Remedies On Default. Upon the occurrence of an Event of Default, at
Lender’s option, all unpaid principal and accrued interest, and all other
amounts payable under this Note shall become immediately due and payable without
presentment, demand, notice of non-payment, protest, or notice of non-payment.
Lender also shall have all other rights, powers, and remedies available under
the Credit Agreement and any other Loan Document, or accorded by law or at
equity. All rights, powers, and remedies of Lender may be exercised at any time
by Lender and from time to time after the occurrence of an Event of Default. All
rights, powers, and remedies of Lender in connection with this Note and any
other Loan Document are cumulative and not exclusive and shall be in addition to
any other rights, powers, or remedies provided by law or equity.

              1.4         Miscellaneous.

              1.4.1   Borrower and all guarantors and endorsers of this Note severally waive (i)
presentment, demand, protest, notice of dishonor, and all other notices; (ii) any release or
discharge arising from any extension of time, discharge of a prior party, release of any or all of
the security for this Note, and (iii) any other cause of release or discharge other than actual
payment in full of all indebtedness evidenced by or arising under this Note.

              1.4.2    No delay or omission of Lender to exercise any right, whether before or
after an Event of Default, shall impair any such right or shall be construed to be a waiver of any
right or default, and the acceptance of any past-due amount at any time by the Lender shall not be
deemed to be a waiver of the right to require prompt payment when due of any other amounts then
or thereafter due and payable.  The Lender shall not be deemed, by any act or omission, to have
waived any of Lender’s rights or remedies under this Note unless such waiver is in writing and
signed by Lender and then only to the extent specifically set forth in such writing.  A waiver with
reference to one event shall not be construed as continuing or as a bar to or waiver of any right
or remedy as to a subsequent event.

              1.4.3   Lender may accept, indorse, present for payment, and negotiate checks
marked “payment in full” or with words of similar effect without waiving Lender’s right to collect
from Borrower the full amount owed by Borrower.

              1.4.4   Time is of the essence under this Note.  Upon any Event of Default, the
Lender may exercise all rights and remedies provided for in this Note and by law, including, but
not limited to, the right to immediate payment in full of this Note.

              1.4.5   The rights and remedies of the Lender as provided in this Note, in the Credit
Agreement and in law or equity, shall be cumulative and concurrent, and may be pursued
singularly, successively, or together at the sole discretion of the Lender, and may be exercised as
often as occasion therefor shall occur; and the failure to exercise any such right or remedy shall
in no event be construed as a waiver or a release of any such right or remedy.

              1.4.6   It is expressly agreed that if this Note is referred to an attorney or if suit is
brought to collect this Note or any amount due under this Note, or to enforce or protect any rights
conferred upon Lender by this Note then Borrower promises and agrees to pay on demand all
costs, including without limitation, reasonable attorneys’ fees, incurred by Lender in the
enforcement of Lender’s rights and remedies under this Note, and such other agreements.

                                                      3

              1.4.7   The terms, covenants, and conditions contained in this Note shall be binding
upon the heirs, executors, administrators, successors, and assigns of Borrower, and each of them,
and shall inure to the benefit of the heirs, executors, administrators, successors and assigns of
Lender.

              1.4.8   This Note shall be construed under and governed by the laws of the State of
California without regard to conflicts of law.

              1.4.9     No provision of this Note shall be construed or so operate as to require the
Borrower to pay interest at a greater rate than the maximum allowed by applicable state or federal
law.  Should any interest or other charges paid or payable by the Borrower in connection with this
Note or the Loan result in the computation or earning of interest in excess of the maximum
allowed by applicable state or federal law, then any and all such excess shall be and the same is
hereby waived by Lender, and any and all such excess paid shall be credited automatically against
and in reduction of the outstanding principal balance due of the Loan, and the portion of said
excess which exceeds such principal balance shall be paid by Lender to the Borrower.

                                                       4

BORROWER:  BIOTIME, INC.

                           By _____________________________________________

                           Title ___________________________________________

                           By _____________________________________________

                           Title ___________________________________________

	

                                                      5

                                                                                                          EXHIBIT B

                                                 Warrant Agreement

                                            Dated as of March 27, 2001

                                                     6

              WARRANT AGREEMENT, dated as of March 27, 2001, between BioTime, Inc., a
California corporation (the “Company”), and Alfred D. Kingsley (the “Lender”).

     The
Company proposes to issue a Common Share Purchase Warrant, as hereinafter
described (the “Warrants”), to purchase up to an aggregate of 50,000
of its Common Shares, no par value (the “Common Stock”) (the shares of
Common Stock issuable upon exercise of the Warrants being referred to herein as
the “Warrant Shares”), in connection with the Revolving Line of Credit
Agreement of even date (the “Credit Agreement”), between the Company
and the Lender.. 

     In
consideration of the foregoing and for the purpose of defining the terms and
provisions of the Warrant and the respective rights and obligations thereunder
of the Company and each registered owner of the Warrant (the
“Holder”), the Company and the Lender hereby agree as follows: 

     SECTION
1.   Issuance of Warrants; Term of Warrants. Concurrently with the
execution and delivery of this Agreement and the Credit Agreement, the Company
is issuing and delivering to the Lender a Warrant to purchase 50,000 Warrant
Shares, which Warrant shall be represented by a certificate in substantially the
form of Exhibit A hereto. Subject to the terms of this Agreement, a Holder of
any of such Warrant (including any Warrants into which the Warrant may be
divided) shall have the right, which may be exercised at any time prior to 5:00
p.m., New York Time on March 26, 2006 (the “Expiration Date”), to
purchase from the Company the number of fully paid and nonassessable Warrant
Shares which the Holder may at the time be entitled to purchase upon exercise of
any of such Warrant. 

              SECTION 2.    Transferability and Form of Warrant.

              2.1   Registration.  The Warrant shall be numbered and shall be registered on the
books of the Company (the “Warrant Register”) as issued.  The Company and the Warrant Agent
(if appointed) shall be entitled to treat the Holder of any Warrant as the owner in fact thereof for
all purposes and shall not be bound to recognize any equitable or other claim or interest in such
Warrant on the part of any other person, and shall not be liable for any registration of transfer of
any Warrant which is registered or to be registered in the name of a fiduciary or the nominee of
a fiduciary unless made with the actual knowledge that a fiduciary or nominee is committing a
breach of trust in requesting such registration or transfer, or with such knowledge of such facts
that its participation therein amounts to bad faith.  The Warrant shall initially be registered in the
name of the Lender.

              2.2   Restrictions on Exercise and Transfer.  The Warrant may not be exercised,
sold, pledged, hypothecated, transferred or assigned, in whole or in part, unless a registration
statement under the Securities Act of 1933, as amended (the “Act”), and under any applicable state
securities laws is effective therefor or, an exemption from such registration is then available.  Any
exercise, sale, pledge, hypothecation, transfer, or assignment in violation of the foregoing
restriction shall be deemed
null and void and of no binding effect. The Company shall be entitled to obtain,
as a condition precedent to its issuance of any certificates representing
Warrant Shares or any other securities issuable upon any exercise of the
Warrant, a letter or other instrument from the Holder containing such covenants,
representations or warranties by such Holder as reasonably deemed necessary by
Company to effect compliance by the Company with the requirements of applicable
federal and/or state securities laws. 

                                                      1

                 2.3   Transfer. Subject to Section 2.2, the Warrant shall be transferable only on the
Warrant Register upon delivery thereof duly endorsed by the Holder or by his duly authorized
attorney or representative, or accompanied by proper evidence of succession, assignment or
authority to transfer, which endorsement shall be guaranteed by a bank or trust company or a
broker or dealer which is a member of the National Association of Securities Dealers, Inc.  In all
cases of transfer by an attorney, the original power of attorney, duly approved, or a copy thereof,
duly certified, shall be deposited and remain with the Company (or the Warrant Agent, if
appointed).  In case of transfer by executors, administrators, guardians or other legal
representatives, duly authenticated evidence of their authority shall be produced, and may be
required to be deposited and remain with the Company (or the Warrant Agent, if appointed) in its
discretion.  Upon any registration of transfer, the Company shall execute and deliver (or if
appointed, the Warrant Agent shall countersign and deliver) a new Warrant or Warrants to the
persons entitled thereto.

               2.4  Form of Warrant.  The text of the Warrant and of the Purchase Form shall be
substantially as set forth in Exhibit A attached hereto.  The price per Warrant Share and the
number of Warrant Shares issuable upon exercise of each Warrant are subject to adjustment upon
the occurrence of certain events, all as hereinafter provided.  The Warrants shall be executed on
behalf of the Company by its Chairman of the Board, President or one of its Vice Presidents,
under its corporate seal reproduced thereon attested by its Secretary or Assistant Secretary.  The
signature of any such officers on the Warrants may be manual or facsimile, provided, however,
that the signature of any such officers must be manual until such time as a Warrant Agent is
appointed.

              Warrants bearing the manual or facsimile signatures of individuals who were at any
time the proper officers of the Company shall bind the Company, notwithstanding that such
individuals or any one of them shall have ceased to hold such offices prior to the delivery of such
Warrants or did not hold such offices on the date of this Agreement.

              In the event that the Company shall appoint a Warrant Agent to act on its behalf in
connection with the division, transfer, exchange or exercise of Warrants, the Warrants issued after
the date of such appointment shall be dated as of the date of countersignature thereof by the
Warrant Agent upon division, exchange, substitution or transfer.  Until such time as the Company
shall appoint a Warrant Agent, Warrants shall be dated as of the date of execution thereof by the
Company either upon initial issuance or upon division, exchange, substitution or transfer.

     SECTION
3.   Countersignature of Warrants. In the event that the Company shall
appoint a Warrant Agent to act on its behalf in connection with the division,
transfer, exchange or exercise of Warrants, the Warrants issued after the date
of such appointment shall be countersigned by the Warrant Agent (or any
successor to the Warrant Agent then acting as warrant agent) and shall not be
valid for any purpose unless so countersigned. Warrants may be countersigned,
however, by the Warrant Agent (or by its successor as warrant agent hereunder)
and may be delivered by the Warrant Agent, notwithstanding that the persons
whose manual or facsimile signatures appear thereon as proper officers of the
Company shall have ceased to be such officers at the time of such
countersignature, issuance or delivery. The Warrant Agent (if so appointed)
shall, upon written instructions of the Chairman of the Board, the President, an
Executive or Senior Vice President, the Treasurer or the Controller of the
Company, countersign, issue and deliver Warrants entitling the Holders thereof
to purchase not more than 50,000 Warrant Shares (subject to adjustment pursuant
to Section 10 hereof) and shall countersign and deliver Warrants as otherwise
provided in this Agreement. 

                                                      2

     SECTION
4.   Exchange of Warrant Certificates. Each Warrant certificate may be
exchanged, at the option of the Holder thereof, for another Warrant certificate
or Warrant certificates in different denominations entitling the Holder or
Holders thereof to purchase a like aggregate number of Warrant Shares as the
certificate or certificates surrendered then entitle each Holder to purchase.
Any Holder desiring to exchange a Warrant certificate or certificates shall make
such request in writing delivered to the Company at its principal office (or, if
a Warrant Agent is appointed, the Warrant Agent at its principal office) and
shall surrender, properly endorsed, the certificate or certificates to be so
exchanged. Thereupon, the Company (or, if appointed, the Warrant Agent) shall
execute and deliver to the person entitled thereto a new Warrant certificate or
certificates, as the case may be, as so requested, in such name or names as such
Holder shall designate. 

          SECTION 5.    Exercise of Warrants; Listing.

              5.1   Exercise of Warrants.  A Warrant may be exercised upon surrender of the
certificate or certificates evidencing the Warrants to be exercised, together with the form of
election to purchase on the reverse thereof duly filled in and signed, which signature shall be
guaranteed by a bank or trust company or a broker or dealer which is a member of the National
Association of Securities Dealers, Inc., to the Company at its principal office (or if appointed, the
principal office of the Warrant Agent) and upon payment of the Warrant Price (as defined in and
determined in accordance with the provisions of Sections 9 and 10 hereof) to the Company (or if
appointed, to the Warrant Agent for the account of the Company), for the number of Warrant
Shares in respect of which such Warrants are then exercised.  Payment of the aggregate Warrant
Price (defined in Section 9 herein) shall be made in cash or by certified or bank cashier’s check.

                                                   3

     Subject
to Section 6 hereof, upon the surrender of the Warrant and payment of the
Warrant Price as aforesaid, the Company (or if appointed, the Warrant Agent)
shall cause to be issued and delivered with all reasonable dispatch to or upon
the written order of the Holder and in such name or names as the Holder may
designate, a certificate or certificates for the number of full Warrant Shares
so purchased upon the exercise of such Warrant, together with cash, as provided
in Section 11 hereof, in respect of any fractional Warrant Shares otherwise
issuable upon such surrender. Such certificate or certificates shall be deemed
to have been issued and any person so designated to be named therein shall be
deemed to have become a holder of record of such Warrant Shares as of the date
of the surrender of such Warrants and payment of the Warrant Price, as
aforesaid. The rights of purchase represented by the Warrant shall be
exercisable, at the election of the Holder thereof, either in full or from time
to time in part and, in the event that a certificate evidencing the Warrant is
exercised in respect of less than all of the Warrant Shares purchasable on such
exercise at any time prior to the date of expiration of the Warrant, a new
certificate evidencing the unexercised portion of the Warrant will be issued,
and the Warrant Agent (if so appointed) is hereby irrevocably authorized to
countersign and to deliver the required new Warrant certificate or certificates
pursuant to the provisions of this Section and Section 3 hereof, and the
Company, whenever required by the Warrant Agent (if appointed), will supply the
Warrant Agent with Warrant certificates duly executed on behalf of the Company
for such purpose. 

              5.2   Listing of Shares on Securities Exchange; Exchange Act Registration.  The
Company will promptly use its best efforts to cause the Warrant Shares to be listed, subject to
official notice of issuance, on all national securities exchanges on which the Common Stock is
listed and whose rules and regulations require such listing, as soon as possible following the date
hereof.

              The Company will promptly notify the Holders in the event that the Company plans
to register the Warrants with the Securities and Exchange Commission under the Securities
Exchange Act of 1934, as amended (the “Exchange Act”).

     SECTION
6.   Payment of Taxes. The Company will pay all documentary stamp taxes, if
any, attributable to the initial issuance of Warrant Shares upon the exercise of
Warrants; provided, however, that the Company shall not be required to pay any
tax or taxes which may be payable in respect of any transfer involved in the
issue or delivery of any Warrant or certificates for Warrant Shares in a name
other than that of the registered Holder of such Warrants. 

     SECTION
7.   Mutilated or Missing Warrants. In case any of the certificates
evidencing the Warrants shall be mutilated, lost, stolen or destroyed, the
Company may in its discretion issue and deliver (and, if appointed, the Warrant
Agent shall countersign and deliver) in exchange and substitution for and upon
cancellation of the mutilated Warrant certificate, or in lieu of and
substitution for the Warrant certificate lost, stolen or destroyed, a new
Warrant certificate of like tenor, but only upon receipt of evidence reasonably
satisfactory to the Company and the Warrant Agent (if so appointed) of such
loss, theft or destruction of such Warrant and an indemnity or bond, if
requested, also reasonably satisfactory to them. An applicant for such a
substitute
Warrant certificate shall
also comply with such other reasonable regulations and pay such other reasonable
charges as the Company (or the Warrant Agent, if so appointed) may prescribe.

                                                    4

              SECTION 8.    Reservation of Warrant Shares; Purchase and Cancellation of Warrants.

               8.1   Reservation of Warrant Shares.  There have been reserved, and the Company
shall at all times keep reserved, out of its authorized Common Stock, a number of shares of
Common Stock sufficient to provide for the exercise of the rights of purchase represented by the
outstanding Warrants and any additional Warrants issuable hereunder.  The Transfer Agent for
the Common Stock and every subsequent transfer agent for any shares of the Company’s capital
stock issuable upon the exercise of any of the rights of purchase aforesaid will be irrevocably
authorized and directed at all times to reserve such number of authorized shares as shall be
required for such purpose.  The Company will keep a copy of this Agreement on file with the
Transfer Agent for the Common Stock and with every subsequent transfer agent for any shares
of the Company’s capital stock issuable upon the exercise of the rights of purchase represented by
the Warrants.  The Warrant Agent, if appointed, will be irrevocably authorized to requisition from
time to time from such Transfer Agent the stock certificates required to honor outstanding
Warrants upon exercise thereof in accordance with the terms of this Agreement.  The Company
will supply such Transfer Agent with duly executed stock certificates for such purposes and will
provide or otherwise make available any cash which may be payable as provided in Section 11
hereof.  The Company will furnish such Transfer Agent a copy of all notices of adjustments and
certificates related thereto, transmitted to each Holder pursuant to subsection 10.3 hereof.

               8.2  Purchase of Warrants by the Company.  The Company shall have the right,
except as limited by law, other agreements or herein, with the consent of the Holder, to purchase
or otherwise acquire Warrants at such times, in such manner and for such consideration as it may
deem appropriate.

               8.3   Cancellation of Warrants.  In the event the Company shall purchase or
otherwise acquire Warrants, the same shall thereupon be cancelled and retired.  The Warrant
Agent (if so appointed) shall cancel any Warrant surrendered for exchange, substitution, transfer
or exercise in whole or in part.

     SECTION
9.   Warrant Price. Subject to any adjustments required by Section 10
hereof, the price per share at which Warrant Shares shall be purchasable upon
exercise of a Warrant (as to any particular Warrant, the “Warrant
Price”) shall be Eight Dollars and Thirty-One Cents ($8.31) per share. 

     SECTION
10.   Adjustment of Warrant Price and Number of Warrant Shares. The number
and kind of securities purchasable upon the exercise of each Warrant and the
Warrant Price shall be subject to adjustment from time to time upon the
happening of certain events, as hereinafter defined. 

               10.1    Adjustments.  The number of Warrant Shares purchasable upon the exercise
of each Warrant and the Warrant Price shall be subject to adjustment as follows:

                         10.1.1            In the event that the Company shall (i) pay a dividend in shares of
Common Stock or make a
distribution in shares of Common Stock, (ii) subdivide its outstanding shares of
Common Stock, (iii) combine its outstanding shares of Common Stock into a
smaller number of shares of Common Stock or (iv) reclassify or change (including
a change to the right to receive, or a change into, as the case may be (other
than with respect to a merger or consolidation pursuant to the exercise of
appraisal rights), shares of stock, other securities, property, cash or any
combination thereof) its Common Stock (including

                                                 5

 any such reclassification or
change in connection with a consolidation or merger in which the Company is the
surviving corporation), the number of Warrant Shares purchasable upon exercise
of each Warrant immediately prior thereto shall be adjusted so that the Holder
of each Warrant shall be entitled to receive the kind and number of Warrant
Shares or other securities of the Company or other property which he would have
owned or have been entitled to receive after the happening of any of the events
described above, had such Warrant been exercised immediately prior to the
happening of such event or any record date with respect thereto. An adjustment
made pursuant to this paragraph (a) shall become effective immediately after the
effective date of such event retroactive to the record date, if any, for such
event. 

                         10.1.2            In case the Company shall issue rights, options or warrants to all
holders of its outstanding
Common Stock, without any charge to such holders, entitling them to subscribe
for or purchase shares of Common Stock at a price per share which is lower at
the record date mentioned below than the then current market price per share of
Common Stock (as defined in paragraph (d) below), the number of Warrant Shares
thereafter purchasable upon the exercise of each Warrant shall be determined by
multiplying the number of Warrant Shares theretofore purchasable upon exercise
of each Warrant by a fraction, of which the numerator shall be the number of
shares of Common Stock outstanding on the date of issuance of such rights,
options or warrants plus the number of additional shares of Common Stock offered
for subscription or purchase in connection with such rights, options or
warrants, and of which the denominator shall be the number of shares of Common
Stock outstanding on the date of issuance of such rights, options or warrants
plus the number of shares which the aggregate offering price of the total number
of shares of Common Stock so offered would purchase at the current market price
per share of Common Stock at such record date. Such adjustment shall be made
whenever such rights, options or warrants are issued, and shall become effective
immediately after the record date for the determination of stockholders entitled
to receive such rights, options or warrants. 

                         10.1.3            In case the Company shall distribute to all holders of its shares of
Common Stock, (including
any distribution made in connection with a merger in which the Company is the
surviving corporation), evidences of its indebtedness or assets (excluding cash,
dividends or distributions payable out of consolidated earnings or earned
surplus and dividends or distributions referred to in paragraph (a) above) or
rights, options or warrants, or convertible or exchangeable securities
containing the right to subscribe for or purchase shares of Common Stock
(excluding those referred to in paragraph (b) above), then in each case the
number of Warrant Shares thereafter purchasable upon the exercise of each
Warrant shall be determined by multiplying the number of Warrant Shares
theretofore purchasable upon the exercise of each Warrant by a fraction, of
which the numerator shall be the then current market price per share of Common
Stock (as defined in paragraph (d) below) on the date of such distribution, and
of which the denominator shall be the then current market price per share of
Common Stock, less the then fair value (as determined by the Board of Directors
of the Company or, in the case of Warrants held by the Lender, an independent
investment banker which shall be mutually agreeable to the parties, whose
determination, in each case, shall be conclusive) of the portion of the assets
or evidences of indebtedness so distributed or of such subscription rights,
options or warrants, or of such convertible or exchangeable securities
applicable to one share of Common Stock. Such adjustment shall be made whenever
any such distribution is made, and shall become effective on the date of
distribution retroactive to the record date for the determination of
shareholders entitled to receive such distribution.

                                                     6

                         10.1.4            For the purpose of any computation under paragraphs (b) and (c) of
this Section, the current
market price per share of Common Stock at any date shall be the average of the
daily last sale prices for the 20 consecutive trading days ending one trading
day prior to the date of such computation. The closing price for each day shall
be the last reported sales price regular way or, in case no such reported sale
takes place on such day, the average of the closing bid and asked prices regular
way for such day, in each case on the principal national securities exchange on
which the shares of Common Stock are listed or admitted to trading or, if not so
listed or admitted to trading, the last sale price of the Common Stock on the
Nasdaq Stock Market or any comparable system. If the current market price of the
Common Stock cannot be so determined, the Board of Directors of the Company
shall reasonably determine the current market price on the basis of such
quotations as are available.

                         10.1.5            No adjustment in the number of Warrant Shares purchasable
hereunder shall be required
unless such adjustment would require an increase or decrease of at least one
percent (1%) in the number of Warrant Shares purchasable upon the exercise of
each Warrant; provided, however, that any adjustments which by reason of this
paragraph (e) are not required to be made shall be carried forward and taken
into account in any subsequent adjustment. All calculations shall be made with
respect to the number of Warrant Shares purchasable hereunder, to the nearest
tenth of a share and with respect to the Warrant Price payable hereunder, to the
nearest whole cent.

                          10.1.6            Whenever the number of Warrant Shares purchasable upon the
exercise of each Warrant is
adjusted, as herein provided, the Warrant Price payable upon exercise of each
Warrant shall be adjusted by multiplying such Warrant Price immediately prior to
such adjustment by a fraction, of which the numerator shall be the number of
Warrant Shares purchasable upon the exercise of each Warrant immediately prior
to such adjustment, and of which the denominator shall be the number of Warrant
Shares purchasable immediately thereafter. 

                          10.1.7            No adjustment in the number of Warrant Shares purchasable upon
the exercise of each
Warrant need be made under paragraphs (b) and (c) if the Company issues or
distributes to each Holder of Warrants the rights options, warrants, or
convertible or exchangeable securities, or evidences of indebtedness or assets
referred to in those paragraphs which each Holder of Warrants would have been
entitled to receive had the Warrants been exercised prior to the happening of
such event or the record date with respect thereto. No adjustment need be made
for a change in the par value of the Warrant Shares.

                         10.1.8            For the purpose of this subsection 10.1, the term “shares of Common
Stock” shall mean (i)
the class of stock designated as the Common Stock of the Company at the date of
this Agreement, or (ii) any other class of stock resulting from successive
changes or reclassifications of such shares consisting solely of changes in par
value, or from par value to no par value, or from no par value to par value. In
the event that at any time, as a result of an adjustment made pursuant to
paragraph (a) above, the Holders shall become entitled to purchase any
securities of the Company other than shares of Common Stock, thereafter the
number of such other shares so purchasable upon exercise of each Warrant and the
Warrant Price of such shares shall be subject to adjustment from time to time in
a manner and on terms as nearly equivalent as practicable to the provisions with
respect to the Warrant Shares contained in paragraphs (a) through (i),
inclusive, and the provisions of Section 5 and subsections 10.2 through 10.5,
inclusive, with respect to the Warrant Shares, shall apply on like terms to any
such other securities.
 

                                                      7

                         10.1.9            Upon the expiration of any rights, options, warrants or conversion
or exchange privileges, if
any thereof shall not have been exercised, the Warrant Price and the number of
Warrant Shares purchasable upon the exercise of each Warrant shall, upon such
expiration, be readjusted and shall thereafter be such as it would have been had
it been originally adjusted (or had the original adjustment not been required,
as the case may be) as if (A) the only shares of Common Stock so issued were the
shares of Common Stock, if any, actually issued or sold upon the exercise of
such rights, options, warrants or conversion or exchange rights and (B) such
shares of Common Stock, if any, were issued or sold for the consideration
actually received by the Company upon such exercise plus the aggregate
consideration, if any, actually received by the Company for the issuance, sale
or grant of all such rights, options, warrants or conversion or exchange rights
whether or not exercised. 

               10.2    Voluntary Adjustment by the Company.  The Company may at its option, at
any time during the term of the Warrants, reduce the then current Warrant Price to any amount
deemed appropriate by the Board of Directors of the Company.

               10.3    Notice of Adjustment. Whenever the number of Warrant Shares purchasable
upon the exercise of each Warrant or the Warrant Price of such Warrant Shares is adjusted, as
herein provided, the Company shall, or in the event that a Warrant Agent is appointed, the
Company shall cause the Warrant Agent promptly to, mail by first class, postage prepaid, to each
Holder notice of such adjustment or adjustments.  Such notice shall set forth the number of
Warrant Shares purchasable
upon the exercise of each Warrant and the Warrant Price of such Warrant Shares
after such adjustment, setting forth a brief statement of the facts requiring
such adjustment and setting forth the computation by which such adjustment was
made. 

               10.4    No Adjustment for Dividends.  Except as provided in subsection 10.1, no
adjustment in respect of any dividends shall be made during the term of a Warrant or upon the
exercise of a Warrant.

               10.5    Preservation of Purchase Rights Upon Merger, Consolidation, etc.  In case
of any consolidation of the Company with or merger of the Company into another corporation or
in case of any sale, transfer or lease to another corporation of all or substantially all the property
of the Company, the Company or such successor or purchasing corporation, as the case may be,
shall execute an agreement that each Holder shall have the right thereafter, upon such Holder’s
election, either (i) upon payment of the Warrant Price in effect immediately prior to such action,
to purchase upon exercise of each Warrant the kind and amount of shares and other securities and
property (including cash) which he would have owned or have been entitled to receive after the
happening of such consolidation, merger, sale, transfer or lease had such Warrant been exercised
immediately prior to such action (such shares and other securities and property (including cash)
being referred to as the “Sale Consideration”) or (ii) to receive, in cancellation of such Warrant
(and in lieu of paying the Warrant price and exercising such Warrant), the Sale Consideration less
a portion thereof having a fair market value (as reasonably determined by the Company) equal to
the Warrant Price (it being understood that, if the Sale Consideration consists of more than one
type of shares, other securities or property, the amount of each type of shares, other securities or
property to be received

                                                      8

shall be reduced proportionately); provided, however, that no adjustment
in respect of dividends, interest or other income on or from such shares or other securities and
property shall be made during the term of a Warrant or upon the exercise of a Warrant.  The
Company shall mail by first class mail, postage prepaid, to each Holder, notice of the execution
of any such agreement.  Such agreement shall provide for adjustments, which shall be as nearly
equivalent as may be practicable to the adjustments provided for in this Section 10.  The
provisions of this subsection 10.5 shall similarly apply to successive consolidations, mergers,
sales, transfers or leases.  The Warrant Agent (if appointed) shall be under no duty or
responsibility to determine the correctness of any provisions contained in any such agreement
relating to the kind or amount of shares of stock or other securities or property receivable upon
exercise of Warrants or with respect to the method employed and provided therein for any
adjustments and shall be entitled to rely upon the provisions contained in any such agreement.

                    10.6   Statement on Warrants.  Irrespective of any adjustments in the Warrant Price
or the number or kind of shares purchasable upon the exercise of the Warrants, Warrants issued
before or after such adjustment may continue to express the same price and number and kind of
shares as are stated in the Warrants initially issuable pursuant to this Agreement.

      SECTION 11.    Fractional Interests.  The Company shall not be required to issue fractional
Warrant Shares on the exercise of Warrants.  If more than one Warrant shall be presented for
exercise in full at the
same time by the same Holder, the number of full Warrant Shares which shall be
issuable upon the exercise thereof shall be computed on the basis of the
aggregate number of Warrant Shares purchasable on exercise of the Warrants so
presented. If any fraction of a Warrant Share would, except for the provisions
of this Section 11, be issuable on the exercise of any Warrant (or specified
portion thereof), the Company shall pay an amount in cash equal to the average
of the daily closing sale prices (determined in accordance with paragraph (d) of
subsection 10.1) per share of Common Stock for the 20 consecutive trading days
ending one trading day prior to the date the Warrant is presented for exercise,
multiplied by such fraction. 

     SECTION
12.   No Rights as Shareholders; Notices to Holders. Nothing contained in
this Agreement or in any of the Warrants shall be construed as conferring upon
the Holders or their transferees the right to vote or to receive dividends or to
consent or to receive notice as shareholders in respect of any meeting of
shareholders for the election of directors of the Company or any other matter,
or any rights whatsoever as shareholders of the Company. If, however, at any
time prior to the expiration of the Warrants and prior to their exercise, any of
the following events shall occur: 

               12.1.1     the Company shall declare any dividend payable in any securities upon its
shares of Common Stock or make any distribution (other than a regular cash dividend, as such
dividend may be increased from time to time, or a dividend payable in shares of Common Stock)
to the holders of its shares of Common Stock; or

               12.1.2       the Company shall offer to the holders of its shares of Common Stock on
a pro rata basis any cash, additional shares of Common Stock or other securities of the Company
or any right to subscribe for or purchase any thereof; or

                                                    9

                 12.1.3             a dissolution, liquidation or winding up of the Company (other than
in connection with a consolidation, merger, sale, transfer or lease of all or substantially all of its
property, assets, and business as an entirety) shall be proposed,
then in any one or more of
said events the Company shall (a) give notice in writing of such event as
provided in Section 14 hereof and (b) if the Warrants have been registered
pursuant to the Act, cause notice of such event to be published once in The Wall
Street Journal (national edition), such giving of notice and publication to be
completed at least 10 days prior to the date fixed as a record date or the date
of closing the transfer books for the determination of the stockholders entitled
to such dividend, distribution, or subscription rights or for the determination
of stockholders entitled to vote on such proposed dissolution, liquidation or
winding up or the date of expiration of such offer. Such notice shall specify
such record date or the date of closing the transfer books or the date of
expiration, as the case may be. Failure to publish, mail or receive such notice
or any defect therein or in the publication or mailing thereof shall not affect
the validity of any action in connection with such dividend, distribution or
subscription rights, or such proposed dissolution, liquidation or winding up, or
such offer. 

        SECTION
13.   Appointment of Warrant Agent. At such time as the Company shall
register Warrants under the Act, the Company shall appoint a Warrant Agent to
act on behalf of the Company in connection with the issuance, division, transfer
and exercise of Warrants. At such time as the Company appoints a Warrant Agent,
the Company shall enter into a new Warrant Agreement with the Warrant Agent
pursuant to which all new Warrants will be issued upon registration of transfer
or division, which will reflect the appointment of the Warrant Agent, as well as
additional customary provisions as shall be reasonably requested by the Warrant
Agent in connection with the performance of its duties. In the event that a
Warrant Agent is appointed, the Company shall (i) promptly notify the Holders of
such appointment and the place designated for transfer, exchange and exercise of
the Warrants, and (ii) take such steps as are necessary to insure that Warrants
issued prior to such appointment may be exchanged for Warrants countersigned by
the Warrant Agent. 

     SECTION
14.   Notices; Principal Office. Any notice pursuant to this Agreement by
the Company or by any Holder to the Warrant Agent (if so appointed), or by the
Warrant Agent (if so appointed) or by any Holder to the Company, shall be in
writing and shall be delivered in person, or mailed first class, postage prepaid
(a) to the Company, at its office, Attention: President or (b) to the Warrant
Agent, at its offices as designated at the time the Warrant Agent is appointed.
The address of the principal office of the Company is 935 Pardee Street,
Berkeley, California 94710. Each party hereto may from time to time change the
address to which notices to it are to be delivered or mailed hereunder by notice
to the other party. 

                                 Any notice mailed pursuant to this Agreement by the Company or the Warrant
Agent to the Holders shall be in writing and shall be mailed first class, postage prepaid, or
otherwise delivered, to such Holders at their respective addresses on the books of the Company
or the Warrant Agent, as the case may be.

     SECTION
15.   Successors. Except as expressly provided herein to the contrary, all
the covenants and provisions of this Agreement by or for the benefit of the
Company and the Lender shall bind and inure to the benefit of their respective
successors and permitted assigns hereunder. 

10

     SECTION
16.   Merger or Consolidation of the Company. The Company will not merge or
consolidate with or into, or sell, transfer or lease all or substantially all of
its property to, any other corporation unless the successor or purchasing
corporation, as the case may be (if not the Company), shall expressly assume, by
supplemental agreement, the due and punctual performance and observance of each
and every covenant and condition of this Agreement to be performed and observed
by the Company. 

     SECTION  17.    Investment Representations.  Lender represents and warrants to BioTime
that:

                  17.1.1      Lender has received and read the Company’s financial statements for the
year ended on December 31, 2000, as will be included in its Form 10-K for such fiscal year, its
annual report on Form 10-K for the fiscal year ended December 31, 1999, and quarterly report
on Form 10-Q for the fiscal quarter and nine months ended September 30, 2000, and Form 8-K
(the “Disclosure Documents”).  Lender is relying on the information provided in the Disclosure
Documents or otherwise communicated to Lender in writing by the Company.  Lender has not
relied on any statement or representations inconsistent with those contained in the Disclosure
Documents.  Lender has had a reasonable opportunity to ask questions of and receive answers
from the executive officers and directors of the Company, or one or more of its officers,
concerning the Company and to obtain additional information, to the extent possessed or
obtainable without unreasonable effort or expense, necessary to verify the information in the
Disclosure Documents.  All such questions have been answered to Lender’s satisfaction;

               17.1.2             Lender understands that the Warrant and the Warrant Shares are being
offered and sold without registration under the Act or qualification under the California Corporate
Securities Law of 1968, or under the laws of other states, in reliance upon the exemptions from
such registration and qualification requirements for non-public offerings.  Lender acknowledges
and understands that the availability of the aforesaid exemptions depends in part upon the accuracy
of certain of the representations, declarations and warranties contained herein, which Lender
hereby makes with the intent that they may be relied upon by the Company and its officers and
directors in determining Lender’s suitability to acquire  the Warrant.  Lender understands and
acknowledges that no federal, state or other agency has reviewed or endorsed the offering of the
Warrant or the Warrant Shares or made any finding or determination as to the fairness of the
offering or completeness of the information in the Disclosure Documents;

               17.1.3        Lender understands that the Warrant and the Warrant Shares may not be
offered, sold, or transferred in any manner, and the Warrant may not be exercised, unless
subsequently registered under the Act, or unless there is an exemption from such registration
available for such offer, sale or transfer;

                17.1.4     Lender has such knowledge and experience in financial and business matters
to enable Lender to utilize the information contained in the Disclosure Documents, or otherwise
made available to Lender to evaluate the merits and risks of an investment in the Warrant and the
Warrant Shares and to make an informed investment decision with respect thereto.

               17.1.5      Lender is acquiring the Warrant solely for Lender’s own account and for
long-term investment purposes, and not with a view to, or for sale in connection with, any
distribution of the Warrant or Warrant Shares; and

                                                 11

               17.1.6       Lender is an “accredited investor,” as such term is defined in Regulation D
promulgated under the Act.

      SECTION 18.    Registration Rights.

               18.1.1    The Company agrees, at its expense, upon written request from the Lender,
to register under the Act, the Warrant and the Warrant Shares and to take such other actions as
may be necessary to allow the Warrant and the Warrant Shares to be freely tradable, without
restrictions, in compliance with all regulatory requirements.  A written request for registration
shall specify the quantity of the Warrant Shares intended to be sold, the plan of distribution and
the identity of the sellers, which may include the Lender and assignees of its rights hereunder
(collectively, “Selling Securities Holders”), and whether the registration shall be pursuant to an
underwritten public offering or a “shelf” registration pursuant to Rule 415 (or similar rule that may
be adopted by the Securities and Exchange Commission).  The Company shall not be obligated
to file more than two such registration statements, other than registration statements on Form S-3.
The Company shall keep such registration statements effective for a period of at least nine months,
except that registration statements on Form S-3 shall be kept effective for at least three years ( or
such lesser period as the parties may agree, but in no event beyond the completion of the
distribution or distributions being made pursuant thereto).  The Company shall utilize Form S-3
if it qualifies for such use.  The Company shall make all filings required with respect to the
registration statements and will use its best efforts to cause such filings to become effective, so that
the Warrant and Warrant Shares being registered shall be registered or qualified for sale under the
securities or blue sky laws of such jurisdictions as shall be reasonably appropriate for distribution
of the Warrant and Warrant Shares covered by the registration statement.  The Company will
furnish to the Selling Securities Holders such numbers of copies of a prospectus, including a
preliminary prospectus, in conformity with the requirements of the Act and such other related
documents as the Selling Securities Holders may reasonably request in order to effect the sale of
the Warrant and Warrant Shares.  To effect any offering pursuant to a registration statement under
this Section, the Company shall enter into an agreement containing customary representations and
warranties, and indemnification and contribution provisions, all for the benefit of Selling Securities
Holders, and, in the case of an Underwritten public offering. an underwriting agreement with an
investment banking firm selected by the Lender and reasonably acceptable to the Company,
containing such customary representations and warranties, and indemnification and contribution
provisions.

               18.1.2    If, at any time, the Company proposes to register any of its securities under
the Act (otherwise than pursuant to paragraph 18(a) above or on a Form S-8 if such form cannot
be used for registration of the Warrant or Warrant Shares pursuant to its terms), the Company
shall, as promptly as practicable, give written notice to the Lender.  The Company shall include
in such registration statement the Warrant and any Warrant Shares proposed to be sold by the
Selling Securities Holders. Notwithstanding the foregoing, if the offering of the Company’s
securities is to be made through underwriters, the Company shall not be required to include the
Warrant and Warrant Shares if and to the extent that the managing underwriter reasonably believes
in good faith that such
inclusion would materially adversely affect such offering unless the Selling
Securities Holders agree to postpone their sales until 10 days after the
distribution is completed.

                                                     12

               18.1.3    The Company shall pay the cost of the registration statements filed pursuant
to this Agreement, including without limitation all registration and filing fees, fees and expenses
of compliance with securities or blue sky laws (including counsel’s fees and expenses in
connection therewith), printing expenses, messenger and delivery expenses, internal expenses of
the Company, listing fees and expenses, and fees and expenses of the Company’s counsel,
independent accountants and other persons retained or employed by the Company. Selling
Securities Holders shall pay any underwriters discounts applicable to the Warrant and Warrant
Shares.

     SECTION
19.   Legends. The Warrants and Warrant Shares issued pursuant to this
Agreement shall bear an appropriate legend, conspicuously disclosing the
restrictions on exercise and transfer under Section 2.2 of this Agreement until
the same are registered for sale under the Act. The Company agrees that upon the
sale of the Warrant and Warrant Shares pursuant to a registration statement or
an exemption, upon the presentation of the certificates containing such a legend
to it’s transfer agent, it will remove such legend. The Company further
agrees to remove the legend at such time as registration under the Act shall no
longer be required. 

     SECTION
20.   Applicable Law. This Agreement and each Warrant issued hereunder
shall be governed by and construed in accordance with the laws of the State of
California, without giving effect to principles of conflict of laws. 

     SECTION
21.   Benefits of this Agreement. Nothing in this Agreement shall be
construed to give to any person or corporation other than the Company, the
Warrant Agent (if appointed) and the Holders any legal or equitable right,
remedy or claim under this Agreement; but this Agreement shall be for the sole
and exclusive benefit of the Company, the Warrant Agent and the Holders of the
Warrants. 

     SECTION
22.   Counterparts. This Agreement may be executed in any number of
counterparts and each of such counterparts shall for all purposes be deemed to
be an original, and all such counterparts shall together constitute but one and
the same instrument. 

              SECTION 23.    Captions. The captions of the Sections and subsections of this Agreement
have been inserted for convenience only and shall have no substantive effect.

                                            13

     IN
WITNESS WHEREOF, the parties hereto have caused this Agreement to be duly
executed, all as of the day and year first above written. 

                                                             
           BIOTIME, INC.

                                                    By:

                                                                 
                     Name: Paul Segall, Ph.D

                                                                                
                                       Title: Chairman and
Chief Executive Officer

Attest:

By:

     Name: Judith Segall

     Title: Secretary

                                                                                    Alfred D.
Kingsley

                                               14

                                                                                                          EXHIBIT A

                            THIS WARRANT HAS NOT BEEN REGISTERED UNDER THE SECURITIES
ACT OF 1933, AS AMENDED, OR UNDER APPLICABLE STATE SECURITIES LAWS.
THIS WARRANT MAY NOT BE EXERCISED, SOLD, PLEDGED, HYPOTHECATED,
TRANSFERRED OR ASSIGNED EXCEPT UNDER AN EFFECTIVE REGISTRATION
STATEMENT UNDER SUCH ACT AND APPLICABLE STATE SECURITIES LAWS,
UNLESS AN EXEMPTION FROM SUCH REGISTRATION IS AVAILABLE.

                                VOID AFTER 5:00 P.M. NEW YORK TIME, March 26, 2006

Certificate No.____                                                                        Warrant to Purchase
                                                                                          [Insert number of Shares]
                                                                                          -------------------------
                                                                                           Shares of Common Stock

	
                                                  BIOTIME, INC.

                                          COMMON SHARE PURCHASE WARRANTS

     This
certifies that, for value received, [Insert name of Holder] or registered
assigns (the “Holder”), is entitled to purchase from BioTime, Inc. a
California corporation (the “Company”), at a purchase price per share
[Insert Warrant Price determined pursuant to Sections 9 and 10 of the Warrant
Agreement] (the “Warrant Price”), the number of its Common Shares, no
par value per share (the “Common Stock”), shown above. The number of
shares purchasable upon exercise of the Common Share Purchase Warrants (the
“Warrants”) and the Warrant Price are subject to adjustment from time
to time as set forth in the Warrant Agreement referred to below. Outstanding
Warrants not exercised prior to 5:00 p.m., New York time, on March 26, 2006
shall thereafter be void. 

     Subject
to restriction specified in the Warrant Agreement, Warrants may be exercised in
whole or in part by presentation of this Warrant Certificate with the Purchase
Form on the reverse side hereof duly executed, which signature shall be
guaranteed by a bank or trust company or a broker or dealer which is a member of
the National Association of Securities Dealers, Inc., and simultaneous payment
of the Warrant Price (or as otherwise set forth in Section 10.5) of the Warrant
Agreement at the principal office of the Company (or if a Warrant Agent is
appointed, at the principal office of the Warrant Agent). Payment of such price
shall be made in cash or by certified or bank cashier’s check. As provided
in the Warrant Agreement, the Warrant Price and the number or kind of shares
which may be purchased upon the exercise of the Warrant evidenced by this
Warrant Certificate are, upon the happening of certain events, subject to
modification and adjustment. 

                                                   15

     This
Warrant Certificate is issued under and in accordance with a Warrant Agreement
dated as of March 27, 2001 between the Company and Alfred D. Kingsley and is
subject to the terms and provisions contained in the Warrant Agreement, to all
of which the Holder of this Warrant Certificate by acceptance of this Warrant
Certificate consents. A copy of the Warrant Agreement may be obtained by the
Holder hereof upon written request to the Company. In the event that pursuant to
Section 13 of the Warrant Agreement a Warrant Agent is appointed and a new
warrant agreement entered into between the Company and such Warrant Agent, then
such new warrant agreement shall constitute the Warrant Agreement for purposes
hereof and this Warrant Certificate shall be deemed to have been issued pursuant
to such new warrant agreement. 

     Upon
any partial exercise of the Warrant evidenced by this Warrant Certificate, there
shall be issued to the Holder hereof a new Warrant Certificate in respect of the
shares of Common Stock as to which the Warrant evidenced by this Warrant
Certificate shall not have been exercised. This Warrant Certificate may be
exchanged at the office of the Company (or the Warrant Agent, if appointed) by
surrender of this Warrant Certificate properly endorsed either separately or in
combination with one or more other Warrant Certificates for one or more new
Warrant Certificates evidencing the right of the Holder thereof to purchase the
aggregate number of shares as were purchasable on exercise of the Warrants
evidenced by the Warrant Certificate or Certificates exchanged. No fractional
shares will be issued upon the exercise of any Warrant, but the Company will pay
the cash value thereof determined as provided in the Warrant Agreement. This
Warrant Certificate is transferable at the office of the Company (or the Warrant
Agent, if appointed) in the manner and subject to the limitations set forth in
the Warrant Agreement. 

     The
Holder hereof may be treated by the Company, the Warrant Agent (if appointed)
and all other persons dealing with this Warrant Certificate as the absolute
owner hereof for any purpose and as the person entitled to exercise the rights
represented hereby, or to the transfer hereof on the books of the Company, any
notice to the contrary notwithstanding, and until such transfer on such books,
the Company (and the Warrant Agent, if appointed) may treat the Holder hereof as
the owner for all purposes. 

              Neither the Warrant nor this Warrant Certificate entitles any Holder to any of the rights
of a stockholder of the Company.

     [This
Warrant Certificate shall not be valid or obligatory for any purpose until it
shall have been countersigned by the Warrant Agent.]* 

                                                     16

DATED:

                                                     BIOTIME, INC.

(Seal)                                               By:________________________

                                                     Title:_____________________

Attest:____________________

[COUNTERSIGNED:

                                    ,
WARRANT AGENT

By:_________________________]*
         Authorized Signature

--------------------

*        To be part of the Warrant only after the appointment of a Warrant Agent pursuant to
         Section 13 of the Warrant Agreement.

	
                                                   17

                                                      PURCHASE FORM

                                        (To be executed upon exercise of Warrant)

To BioTime, Inc.:

         The undersigned hereby irrevocably elects to exercise the right of purchase represented by the
within Warrant Certificate for, and to purchase thereunder,     shares of Common Stock, as
provided for therein, and tenders herewith payment of the purchase price in full in the form of cash
or a certified or bank cashier’s check in the amount of $      .

         Please issue a certificate or certificates for such shares of Common Stock in the name of, and
pay any cash for any fractional share to:

PLEASE INSERT SOCIAL SECURITY                        NAME
OR OTHER IDENTIFYING NUMBER                          (Please Print Name & Address)
OF ASSIGNEE

                                                     Address   ___________________________

                                                     Signature ___________________________

                                                              NOTE:       The above signature should correspond
                                                                          exactly with the name on the face of
                                                                          this Warrant Certificate or with the
                                                                          name of the assignee appearing in the
                                                                          assignment form below.

	
And, if said number of shares shall not be all the shares purchasable under the within Warrant
Certificate, a new Warrant Certificate is to be issued in the name of said undersigned for the balance
remaining of the share purchasable thereunder less any fraction of a share paid in cash.

                                                        18

                                                       ASSIGNMENT

                              (To be executed only upon assignment of Warrant Certificate)

              For value received,         
hereby sells, assigns and transfers unto          
the within Warrant Certificate, together with all right, title and interest therein, and does hereby
irrevocably constitute and appoint          attorney, to transfer said Warrant Certificate
on the books of the within-named Company, with full power of substitution in the premises.

Dated:___________________                                     ________________________________
                                                              NOTE:       The above signature should correspond
                                                                          exactly with the name on the face of
                                                                          this Warrant Certificate.

	

                                                      19Warrant Agreement

	

                                                 Warrant Agreement

                                            Dated as of March 27, 2001

              WARRANT AGREEMENT, dated as of March 27, 2001, between BioTime, Inc., a
California corporation (the “Company”), and Alfred D. Kingsley (the “Lender”).

     The
Company proposes to issue a Common Share Purchase Warrant, as hereinafter
described (the “Warrants”), to purchase up to an aggregate of 50,000
of its Common Shares, no par value (the “Common Stock”) (the shares of
Common Stock issuable upon exercise of the Warrants being referred to herein as
the “Warrant Shares”), in connection with the Revolving Line of Credit
Agreement of even date (the “Credit Agreement”), between the Company
and the Lender.. 

     In
consideration of the foregoing and for the purpose of defining the terms and
provisions of the Warrant and the respective rights and obligations thereunder
of the Company and each registered owner of the Warrant (the
“Holder”), the Company and the Lender hereby agree as follows: 

     SECTION
1.   Issuance of Warrants; Term of Warrants. Concurrently with the
execution and delivery of this Agreement and the Credit Agreement, the Company
is issuing and delivering to the Lender a Warrant to purchase 50,000 Warrant
Shares, which Warrant shall be represented by a certificate in substantially the
form of Exhibit A hereto. Subject to the terms of this Agreement, a Holder of
any of such Warrant (including any Warrants into which the Warrant may be
divided) shall have the right, which may be exercised at any time prior to 5:00
p.m., New York Time on March 26, 2006 (the “Expiration Date”), to
purchase from the Company the number of fully paid and nonassessable Warrant
Shares which the Holder may at the time be entitled to purchase upon exercise of
any of such Warrant. 

              SECTION 2.    Transferability and Form of Warrant.

               2.1    Registration.  The Warrant shall be numbered and shall be registered on the
books of the Company (the “Warrant Register”) as issued.  The Company and the Warrant Agent
(if appointed) shall be entitled to treat the Holder of any Warrant as the owner in fact thereof for
all purposes and shall not be bound to recognize any equitable or other claim or interest in such
Warrant on the part of any other person, and shall not be liable for any registration of transfer of
any Warrant which is registered or to be registered in the name of a fiduciary or the nominee of
a fiduciary unless made with the actual knowledge that a fiduciary or nominee is committing a
breach of trust in requesting such registration or transfer, or with such knowledge of such facts
that its participation therein amounts to bad faith.  The Warrant shall initially be registered in the
name of the Lender.

               2.2    Restrictions on Exercise and Transfer.  The Warrant may not be exercised,
sold, pledged, hypothecated, transferred or assigned, in whole or in part, unless a registration
statement under the Securities Act of 1933, as amended (the 

                                                 1

“Act”), and under any applicable
state securities laws is effective therefor or, an exemption from such registration is then
available.  Any exercise, sale, pledge, hypothecation, transfer, or assignment in violation of the
foregoing restriction shall
be deemed null and void and of no binding effect. The Company shall be entitled
to obtain, as a condition precedent to its issuance of any certificates
representing Warrant Shares or any other securities issuable upon any exercise
of the Warrant, a letter or other instrument from the Holder containing such
covenants, representations or warranties by such Holder as reasonably deemed
necessary by Company to effect compliance by the Company with the requirements
of applicable federal and/or state securities laws. 

               2.3    Transfer.  Subject to Section 2.2, the Warrant shall be transferable only on
the Warrant Register upon delivery thereof duly endorsed by the Holder or by his duly
authorized attorney or representative, or accompanied by proper evidence of succession,
assignment or authority to transfer, which endorsement shall be guaranteed by a bank or trust
company or a broker or dealer which is a member of the National Association of Securities
Dealers, Inc.  In all cases of transfer by an attorney, the original power of attorney, duly
approved, or a copy thereof, duly certified, shall be deposited and remain with the Company (or
the Warrant Agent, if appointed).  In case of transfer by executors, administrators, guardians or
other legal representatives, duly authenticated evidence of their authority shall be produced, and
may be required to be deposited and remain with the Company (or the Warrant Agent, if
appointed) in its discretion.  Upon any registration of transfer, the Company shall execute and
deliver (or if appointed, the Warrant Agent shall countersign and deliver) a new Warrant or
Warrants to the persons entitled thereto.

                2.4    Form of Warrant.  The text of the Warrant and of the Purchase Form shall be
substantially as set forth in Exhibit A attached hereto.  The price per Warrant Share and the
number of Warrant Shares issuable upon exercise of each Warrant are subject to adjustment upon
the occurrence of certain events, all as hereinafter provided.  The Warrants shall be executed on
behalf of the Company by its Chairman of the Board, President or one of its Vice Presidents,
under its corporate seal reproduced thereon attested by its Secretary or Assistant Secretary.  The
signature of any such officers on the Warrants may be manual or facsimile, provided, however,
that the signature of any such officers must be manual until such time as a Warrant Agent is
appointed.

                Warrants bearing the manual or facsimile signatures of individuals who were at
any time the proper officers of the Company shall bind the Company, notwithstanding that such
individuals or any one of them shall have ceased to hold such offices prior to the delivery of such
Warrants or did not hold such offices on the date of this Agreement.

 2

                In the event that the Company shall appoint a Warrant Agent to act on its behalf in
connection with the division, transfer, exchange or exercise of Warrants, the Warrants issued
after the date of such appointment shall be dated as of the date of countersignature thereof by the
Warrant Agent upon division, exchange, substitution or transfer.  Until such time as the
Company shall appoint a Warrant Agent, Warrants shall be dated as of the date of execution
thereof by the Company either upon initial issuance or upon division, exchange, substitution or
transfer.

     SECTION
3.   Countersignature of Warrants. In the event that the Company shall
appoint a Warrant Agent to act on its behalf in connection with the division,
transfer, exchange or exercise of Warrants, the Warrants issued after the date
of such appointment shall be counter signed by the Warrant Agent (or any
successor to the Warrant Agent then acting as warrant agent) and shall not be
valid for any purpose unless so countersigned. Warrants may be countersigned,
however, by the Warrant Agent (or by its successor as warrant agent hereunder)
and may be delivered by the Warrant Agent, notwithstanding that the persons
whose manual or facsimile signatures appear thereon as proper officers of the
Company shall have ceased to be such officers at the time of such
countersignature, issuance or delivery. The Warrant Agent (if so appointed)
shall, upon written instructions of the Chairman of the Board, the President, an
Executive or Senior Vice President, the Treasurer or the Controller of the
Company, countersign, issue and deliver Warrants entitling the Holders thereof
to purchase not more than 50,000 Warrant Shares (subject to adjustment pursuant
to Section 10 hereof) and shall countersign and deliver Warrants as otherwise
provided in this Agreement. 

     SECTION
4.   Exchange of Warrant Certificates. Each Warrant certificate may be
exchanged, at the option of the Holder thereof, for another Warrant certificate
or Warrant certificates in different denominations entitling the Holder or
Holders thereof to purchase a like aggregate number of Warrant Shares as the
certificate or certificates surrendered then entitle each Holder to purchase.
Any Holder desiring to exchange a Warrant certificate or certificates shall make
such request in writing delivered to the Company at its principal office (or, if
a Warrant Agent is appointed, the Warrant Agent at its principal office) and
shall surrender, properly endorsed, the certificate or certificates to be so
exchanged. Thereupon, the Company (or, if appointed, the Warrant Agent) shall
execute and deliver to the person entitled thereto a new Warrant certificate or
certificates, as the case may be, as so requested, in such name or names as such
Holder shall designate. 

     SECTION 5.    Exercise of Warrants; Listing.

               5.1    Exercise of Warrants.  A Warrant may be exercised upon surrender of the
certificate or certificates evidencing the Warrants to be exercised, together with the form of
election to purchase on the reverse thereof duly filled in and signed, which signature shall be
guaranteed by a bank or trust company or a broker or dealer which is a member of the National
Association of Securities Dealers, Inc., to the Company at its principal office (or if appointed,
the principal office of the Warrant Agent) and upon payment of the Warrant Price (as defined in
and determined in accordance with the provisions of Sections 9 and 10 hereof) to the Company
(or if appointed, to the Warrant Agent for the account of the Company), for the number of
Warrant Shares in respect of which such Warrants are then exercised.  Payment of the aggregate
Warrant Price (defined in Section 9 herein) shall be made in cash or by certified or bank
cashier’s check.

                                                    3

               Subject to Section 6 hereof, upon the surrender of the Warrant and payment of the
Warrant Price as aforesaid, the Company (or if appointed, the Warrant Agent) shall cause to be
issued and delivered with all reasonable dispatch to or upon the written order of the Holder and
in such name or names as the Holder may designate, a certificate or certificates for the number
of full Warrant Shares so purchased upon the exercise of such Warrant, together with cash, as
provided in Section 11 hereof, in respect of any fractional Warrant Shares otherwise issuable
upon such surrender.  Such certificate or certificates shall be deemed to have been issued and
any person so designated to be named therein shall be deemed to have become a holder of record
of such Warrant Shares as of the date of the surrender of such Warrants and payment of the
Warrant Price, as aforesaid.  The rights of purchase represented by the Warrant shall be
exercisable, at the election of the Holder thereof, either in full or from time to time in part and,
in the event that a certificate evidencing the Warrant is exercised in respect of less than all of the
Warrant Shares purchasable on such exercise at any time prior to the date of expiration of the
Warrant, a new certificate evidencing the unexercised portion of the Warrant will be issued, and
the Warrant Agent (if so appointed) is hereby irrevocably authorized to countersign and to
deliver the required new Warrant certificate or certificates pursuant to the provisions of this
Section and Section 3 hereof, and the Company, whenever required by the Warrant Agent (if
appointed), will supply the Warrant Agent with Warrant certificates duly executed on behalf of
the Company for such purpose.

               5.2    Listing of Shares on Securities Exchange; Exchange Act Registration.  The
Company will promptly use its best efforts to cause the Warrant Shares to be listed, subject to
official notice of issuance, on all national securities exchanges on which the Common Stock is
listed and whose rules and regulations require such listing, as soon as possible following the date
hereof.

               The Company will promptly notify the Holders in the event that the Company
plans to register the Warrants with the Securities and Exchange Commission under the Securities
Exchange Act of 1934, as amended (the “Exchange Act”).

     SECTION
6.   Payment of Taxes. The Company will pay all documentary stamp taxes, if
any, attributable to the initial issuance of Warrant Shares upon the exercise of
Warrants; provided, however, that the Company shall not be required to pay any
tax or taxes which may be payable in respect of any transfer involved in the
issue or delivery of any Warrant or certificates for Warrant Shares in a name
other than that of the registered Holder of such Warrants. 

     SECTION
7.   Mutilated or Missing Warrants. In case any of the certificates
evidencing the Warrants shall be mutilated, lost, stolen or destroyed, the
Company may in its discretion issue and deliver (and, if appointed, the Warrant
Agent shall countersign and deliver) in exchange and substitution for and upon
cancellation of  

                                                    4

the mutilated Warrant certificate, or in lieu of and
substitution for the Warrant certificate lost, stolen or destroyed, a new
Warrant certificate of like tenor, but only upon receipt of evidence reasonably
satisfactory to the Company and the Warrant Agent (if so appointed) of such
loss, theft or destruction of such Warrant and an indemnity or
bond, if requested, also reasonably satisfactory to them. An applicant for such
a substitute Warrant certificate shall also comply with such other reasonable
regulations and pay such other reasonable charges as the Company (or the Warrant
Agent, if so appointed) may prescribe. 

      SECTION 8.    Reservation of Warrant Shares; Purchase and Cancellation of Warrants.

               8.1   Reservation of Warrant Shares.  There have been reserved, and the Company
shall at all times keep reserved, out of its authorized Common Stock, a number of shares of
Common Stock sufficient to provide for the exercise of the rights of purchase represented by the
outstanding Warrants and any additional Warrants issuable hereunder.  The Transfer Agent for
the Common Stock and every subsequent transfer agent for any shares of the Company’s capital
stock issuable upon the exercise of any of the rights of purchase aforesaid will be irrevocably
authorized and directed at all times to reserve such number of authorized shares as shall be
required for such purpose.  The Company will keep a copy of this Agreement on file with the
Transfer Agent for the Common Stock and with every subsequent transfer agent for any shares
of the Company’s capital stock issuable upon the exercise of the rights of purchase represented
by the Warrants.  The Warrant Agent, if appointed, will be irrevocably authorized to requisition
from time to time from such Transfer Agent the stock certificates required to honor outstanding
Warrants upon exercise thereof in accordance with the terms of this Agreement.  The Company
will supply such Transfer Agent with duly executed stock certificates for such purposes and will
provide or otherwise make available any cash which may be payable as provided in Section 11
hereof.  The Company will furnish such Transfer Agent a copy of all notices of adjustments and
certificates related thereto, transmitted to each Holder pursuant to subsection 10.3 hereof.

               8.2    Purchase of Warrants by the Company.  The Company shall have the right,
except as limited by law, other agreements or herein, with the consent of the Holder, to purchase
or otherwise acquire Warrants at such times, in such manner and for such consideration as it
may deem appropriate.

               8.3    Cancellation of Warrants.  In the event the Company shall purchase or
otherwise acquire Warrants, the same shall thereupon be cancelled and retired.  The Warrant
Agent (if so appointed) shall cancel any Warrant surrendered for exchange, substitution, transfer
or exercise in whole or in part.

                                                      5

     SECTION
9. Warrant Price. Subject to any adjustments required by Section 10
hereof, the price per share at which Warrant Shares shall be purchasable upon
exercise of a Warrant (as to any particular Warrant, the “Warrant
Price”) shall be Eight Dollars and Thirty-One Cents ($8.31) per share. 

     SECTION 10.    Adjustment of Warrant Price and Number of Warrant Shares.  The
number and kind of securities purchasable upon the exercise of each Warrant and the Warrant
Price shall be subject to adjustment from time to time upon the happening of certain events, as
hereinafter defined.

               10.1    Adjustments.  The number of Warrant Shares purchasable upon the exercise
of each Warrant and the Warrant Price shall be subject to adjustment as follows:

                  (a)        In the event that the Company shall (i) pay a dividend in shares of
Common Stock or make a
distribution in shares of Common Stock, (ii) subdivide its outstanding shares of
Common Stock, (iii) combine its outstanding shares of Common Stock into a
smaller number of shares of Common Stock or (iv) reclassify or change (including
a change to the right to receive, or a change into, as the case may be (other
than with respect to a merger or consolidation pursuant to the exercise of
appraisal rights), shares of stock, other securities, property, cash or any
combination thereof) its Common Stock (including any such reclassification or
change in connection with a consolidation or merger in which the Company is the
surviving corporation), the number of Warrant Shares purchasable upon exercise
of each Warrant immediately prior thereto shall be adjusted so that the Holder
of each Warrant shall be entitled to receive the kind and number of Warrant
Shares or other securities of the Company or other property which he would have
owned or have been entitled to receive after the happening of any of the events
described above, had such Warrant been exercised immediately prior to the
happening of such event or any record date with respect thereto. An adjustment
made pursuant to this paragraph (a) shall become effective immediately after the
effective date of such event retroactive to the record date, if any, for such
event.

                    (b)        In case the Company shall issue rights, options or warrants to all
holders of its outstanding
Common Stock, without any charge to such holders, entitling them to subscribe
for or purchase shares of Common Stock at a price per share which is lower at
the record date mentioned below than the then current market price per share of
Common Stock (as defined in paragraph (d) below), the number of Warrant Shares
thereafter purchasable upon the exercise of each Warrant shall be determined by
multiplying the number of Warrant Shares theretofore purchasable upon exercise
of each Warrant by a fraction, of which the numerator shall be the number of
shares of Common Stock outstanding on the date of issuance of such rights,
options or warrants plus the number of additional shares of Common Stock offered
for subscription or purchase in connection with such rights, options or
warrants, and of which the denominator shall be the number of

                                                 6

 shares of Common
Stock outstanding on the date of issuance of such rights, options or warrants
plus the number of shares which the aggregate offering price of the total number
of shares of Common Stock so offered would purchase at the current market price
per share of Common Stock at such record date. Such adjustment shall be made
whenever such rights, options or warrants are issued, and shall become effective
immediately after the record date for the determination of stockholders entitled
to receive such rights, options or warrants. 

               (c)        In case the Company shall distribute to all holders of its shares of
Common Stock, (including any distribution made in connection with a merger in which the
Company is the surviving
corporation), evidences of its indebtedness or assets (excluding cash, dividends
or distributions payable out of consolidated earnings or earned surplus and
dividends or distributions referred to in paragraph (a) above) or rights,
options or warrants, or convertible or exchangeable securities containing the
right to subscribe for or purchase shares of Common Stock (excluding those
referred to in paragraph (b) above), then in each case the number of Warrant
Shares thereafter purchasable upon the exercise of each Warrant shall be
determined by multiplying the number of Warrant Shares theretofore purchasable
upon the exercise of each Warrant by a fraction, of which the numerator shall be
the then current market price per share of Common Stock (as defined in paragraph
(d) below) on the date of such distribution, and of which the denominator shall
be the then current market price per share of Common Stock, less the then fair
value (as determined by the Board of Directors of the Company or, in the case of
Warrants held by the Lender, an independent investment banker which shall be
mutually agreeable to the parties, whose determination, in each case, shall be
conclusive) of the portion of the assets or evidences of indebtedness so
distributed or of such subscription rights, options or warrants, or of such
convertible or exchangeable securities applicable to one share of Common Stock.
Such adjustment shall be made whenever any such distribution is made, and shall
become effective on the date of distribution retroactive to the record date for
the determination of shareholders entitled to receive such distribution.

               (d)        For the purpose of any computation under paragraphs (b) and (c) of
this Section, the current
market price per share of Common Stock at any date shall be the average of the
daily last sale prices for the 20 consecutive trading days ending one trading
day prior to the date of such computation. The closing price for each day shall
be the last reported sales price regular way or, in case no such reported sale
takes place on such day, the average of the closing bid and asked prices regular
way for such day, in each case on the principal national securities exchange on
which the shares of Common Stock are listed or admitted to trading or, if not so
listed or admitted to trading, the last sale price of the Common Stock on the
Nasdaq Stock Market or any comparable system. If the current market price of the
Common Stock cannot be so determined, the Board of Directors of the Company
shall reasonably determine the current market price on the basis of such
quotations as are available. 

                                                      7

               (e)        No adjustment in the number of Warrant Shares purchasable
hereunder shall be required
unless such adjustment would require an increase or decrease of at least one
percent (1%) in the number of Warrant Shares purchasable upon the exercise of
each Warrant; provided, however, that any adjustments which by reason of this
paragraph (e) are not required to be made shall be carried forward and taken
into account in any subsequent adjustment. All calculations shall be made with
respect to the number of Warrant Shares purchasable hereunder, to the nearest
tenth of a share and with respect to the Warrant Price payable hereunder, to the
nearest whole cent.

               (f)        Whenever the number of Warrant Shares purchasable upon the
exercise of each Warrant is
adjusted, as herein provided, the Warrant Price payable upon exercise of each
Warrant shall be adjusted by multiplying such Warrant Price immediately prior
to such adjustment by a
fraction, of which the numerator shall be the number of Warrant Shares
purchasable upon the exercise of each Warrant immediately prior to such
adjustment, and of which the denominator shall be the number of Warrant Shares
purchasable immediately thereafter. 

               (g)        No adjustment in the number of Warrant Shares purchasable upon
the exercise of each
Warrant need be made under paragraphs (b) and (c) if the Company issues or
distributes to each Holder of Warrants the rights options, warrants, or
convertible or exchangeable securities, or evidences of indebtedness or assets
referred to in those paragraphs which each Holder of Warrants would have been
entitled to receive had the Warrants been exercised prior to the happening of
such event or the record date with respect thereto. No adjustment need be made
for a change in the par value of the Warrant Shares.

               (h)        For the purpose of this subsection 10.1, the term “shares of
Common Stock” shall
mean (i) the class of stock designated as the Common Stock of the Company at the
date of this Agreement, or (ii) any other class of stock resulting from
successive changes or reclassifications of such shares consisting solely of
changes in par value, or from par value to no par value, or from no par value to
par value. In the event that at any time, as a result of an adjustment made
pursuant to paragraph (a) above, the Holders shall become entitled to purchase
any securities of the Company other than shares of Common Stock, thereafter the
number of such other shares so purchasable upon exercise of each Warrant and the
Warrant Price of such shares shall be subject to adjustment from time to time in
a manner and on terms as nearly equivalent as practicable to the provisions with
respect to the Warrant Shares contained in paragraphs (a) through (i),
inclusive, and the provisions of Section 5 and subsections 10.2 through 10.5,
inclusive, with respect to the Warrant Shares, shall apply on like terms to any
such other securities.

                                  8

               (i)        Upon the expiration of any rights, options, warrants or conversion
or exchange privileges, if
any thereof shall not have been exercised, the Warrant Price and the number of
Warrant Shares purchasable upon the exercise of each Warrant shall, upon such
expiration, be readjusted and shall thereafter be such as it would have been had
it been originally adjusted (or had the original adjustment not been required,
as the case may be) as if (A) the only shares of Common Stock so issued were the
shares of Common Stock, if any, actually issued or sold upon the exercise of
such rights, options, warrants or conversion or exchange rights and (B) such
shares of Common Stock, if any, were issued or sold for the consideration
actually received by the Company upon such exercise plus the aggregate
consideration, if any, actually received by the Company for the issuance, sale
or grant of all such rights, options, warrants or conversion or exchange rights
whether or not exercised. 

               10.2    Voluntary Adjustment by the Company.  The Company may at its option, at
any time during the term of the Warrants, reduce the then current Warrant Price to any amount
deemed appropriate by the Board of Directors of the Company.

               10.3    Notice of Adjustment.  Whenever the number of Warrant Shares
purchasable upon the exercise of each Warrant or the Warrant Price of such Warrant Shares is
adjusted, as herein provided, the Company shall, or in the event that a Warrant Agent is
appointed, the Company shall cause the Warrant Agent promptly to, mail by first class, postage
prepaid, to each Holder notice of such adjustment or adjustments.  Such notice shall set forth the
number of Warrant Shares purchasable upon the exercise of each Warrant and the Warrant Price
of such Warrant Shares after such adjustment, setting forth a brief statement of the facts re
quiring such adjustment and setting forth the computation by which such adjustment was made.

               10.4    No Adjustment for Dividends.  Except as provided in subsection 10.1, no

adjustment in respect of any dividends shall be made during the term of a Warrant or upon the
exercise of a Warrant.

               10.5   Preservation of Purchase Rights Upon Merger, Consolidation, etc.  In case
of any consolidation of the Company with or merger of the Company into another corporation or
in case of any sale, transfer or lease to another corporation of all or substantially all the property
of the Company, the Company or such successor or purchasing corporation, as the case may be,
shall execute an agreement that each Holder shall have the right thereafter, upon such Holder’s
election, either (i) upon payment of the Warrant Price in effect immediately prior to such action,
to purchase upon exercise of each Warrant the kind and amount of shares and other securities
and property (including cash) which he would have owned or have been entitled to receive after
the happening of such consolidation, merger, sale, transfer or lease had such Warrant been
exercised immediately prior to such action (such shares and other securities and property
(including cash) being referred to as the “Sale Consideration”) or (ii) to receive, in cancellation
of such Warrant (and in lieu of paying the Warrant price and exercising such Warrant), the Sale
Consideration less a portion thereof having a fair market value (as reasonably determined by the
Company) equal to the Warrant Price (it being understood that, if the Sale 

                                                   9

Consideration consists
of more than one type of shares, other securities or property, the amount of each type of shares,
other securities or property to be received shall be reduced proportionately); provided, however,
that no adjustment in respect of dividends, interest or other income on or from such shares or
other securities and property shall be made during the term of a Warrant or upon the exercise of
a Warrant.  The Company shall mail by first class mail, postage prepaid, to each Holder, notice
of the execution of any such agreement.  Such agreement shall provide for adjustments, which
shall be as nearly equivalent as may be practicable to the adjustments provided for in this Section
10.  The provisions of this subsection 10.5 shall similarly apply to successive consolidations,
mergers, sales, transfers or leases.  The Warrant Agent (if appointed) shall be under no duty or
responsibility to determine the correctness of any provisions contained in any such agreement
relating to the kind or amount of shares of stock or other securities or property receivable upon
exercise of Warrants or with respect to the method employed and provided therein for any
adjustments and shall be entitled to rely upon the provisions contained in any such agreement.

               10.6    Statement on Warrants.  Irrespective of any adjustments in the Warrant
Price or the number or kind of shares purchasable upon the exercise of the Warrants, Warrants
issued before or after such
adjustment may continue to express the same price and number and kind of shares
as are stated in the Warrants initially issuable pursuant to this Agreement.

     SECTION
11.   Fractional Interests. The Company shall not be required to issue
fractional Warrant Shares on the exercise of Warrants. If more than one Warrant
shall be presented for exercise in full at the same time by the same Holder, the
number of full Warrant Shares which shall be issuable upon the exercise thereof
shall be computed on the basis of the aggregate number of Warrant Shares
purchasable on exercise of the Warrants so presented. If any fraction of a
Warrant Share would, except for the provisions of this Section 11, be issuable
on the exercise of any Warrant (or specified portion thereof), the Company shall
pay an amount in cash equal to the average of the daily closing sale prices
(determined in accordance with paragraph (d) of subsection 10.1) per share of
Common Stock for the 20 consecutive trading days ending one trading day prior to
the date the Warrant is presented for exercise, multiplied by such fraction. 

     SECTION
12. No Rights as Shareholders; Notices to Holders. Nothing contained in
this Agreement or in any of the Warrants shall be construed as conferring upon
the Holders or their transferees the right to vote or to receive dividends or to
consent or to receive notice as shareholders in respect of any meeting of
shareholders for the election of directors of the Company or any other matter,
or any rights whatsoever as shareholders of the Company. If, however, at any
time prior to the expiration of the Warrants and prior to their exercise, any of
the following events shall occur: 

                                    10

                  (a)        the Company shall declare any dividend payable in any securities upon its
shares of Common Stock or make any distribution (other than a regular cash dividend, as such
dividend may be increased from time to time, or a dividend payable in shares of Common Stock)
to the holders of its shares of Common Stock; or

                  (b)        the Company shall offer to the holders of its shares of Common Stock on
a pro rata basis any cash, additional shares of Common Stock or other securities of the Company
or any right to subscribe for or purchase any thereof; or

                  (c)        a dissolution, liquidation or winding up of the Company (other than in
connection with a consolidation, merger, sale, transfer or lease of all or substantially all of its
property, assets, and business as an entirety) shall be proposed,

then in any one or more of
said events the Company shall (a) give notice in writing of such event as
provided in Section 14 hereof and (b) if the Warrants have been registered
pursuant to the Act, cause notice of such event to be published once in The Wall
Street Journal (national edition), such giving of notice and publication to be
completed at least 10 days prior to the date fixed as a record date or the date
of closing the transfer books for the determination of the stockholders entitled
to such dividend, distribution, or subscription rights or for the determination
of stockholders entitled to vote on such proposed dissolution, liquidation or
winding up or the date of
expiration of such offer. Such notice shall specify such record date or the date
of closing the transfer books or the date of expiration, as the case may be.
Failure to publish, mail or receive such notice or any defect therein or in the
publication or mailing thereof shall not affect the validity of any action in
connection with such dividend, distribution or subscription rights, or such
proposed dissolution, liquidation or winding up, or such offer.
 

     SECTION
13.   Appointment of Warrant Agent. At such time as the Company shall
register Warrants under the Act, the Company shall appoint a Warrant Agent to
act on behalf of the Company in connection with the issuance, division, transfer
and exercise of Warrants. At such time as the Company appoints a Warrant Agent,
the Company shall enter into a new Warrant Agreement with the Warrant Agent
pursuant to which all new Warrants will be issued upon registration of transfer
or division, which will reflect the appointment of the Warrant Agent, as well as
additional customary provisions as shall be reasonably requested by the Warrant
Agent in connection with the performance of its duties. In the event that a
Warrant Agent is appointed, the Company shall (i) promptly notify the Holders of
such appointment and the place designated for transfer, exchange and exercise of
the Warrants, and (ii) take such steps as are necessary to insure that Warrants
issued prior to such appointment may be exchanged for Warrants countersigned by
the Warrant Agent. 

                                     11

     SECTION
14.   Notices; Principal Office. Any notice pursuant to this Agreement by
the Company or by any Holder to the Warrant Agent (if so appointed), or by the
Warrant Agent (if so appointed) or by any Holder to the Company, shall be in
writing and shall be delivered in person, or mailed first class, postage prepaid
(a) to the Company, at its office, Attention: President or (b) to the Warrant
Agent, at its offices as designated at the time the Warrant Agent is appointed.
The address of the principal office of the Company is 935 Pardee Street,
Berkeley, California 94710. Each party hereto may from time to time change the
address to which notices to it are to be delivered or mailed hereunder by notice
to the other party. 

               Any notice mailed pursuant to this Agreement by the Company or the Warrant
Agent to the Holders shall be in writing and shall be mailed first class, postage prepaid, or
otherwise delivered, to such Holders at their respective addresses on the books of the Company
or the Warrant Agent, as the case may be.

     SECTION
15.   Successors. Except as expressly provided herein to the contrary, all
the covenants and provisions of this Agreement by or for the benefit of the
Company and the Lender shall bind and inure to the benefit of their respective
successors and permitted assigns hereunder. 

     SECTION
16.   Merger or Consolidation of the Company. The Company will not merge or
consolidate with or into, or sell, transfer or lease all or substantially all of
its property to, any other corporation unless the successor or purchasing
corporation, as the case may be (if not the Company), shall expressly assume, by
supplemental agreement, the due and punctual performance and observance of each
and every covenant and condition of this Agreement to be performed and observed
by the Company. 

                                                     12

              SECTION 17.    Investment Representations.  Lender represents and warrants to BioTime
that:

                  (a)        Lender has received and read the Company’s financial statements for the
year ended on December 31, 2000, as will be included in its Form 10-K for such fiscal year, its
annual report on Form 10-K for the fiscal year ended December 31, 1999, and quarterly report
on Form 10-Q for the fiscal quarter and nine months ended September 30, 2000, and Form 8-K
(the “Disclosure Documents”).  Lender is relying on the information provided in the Disclosure
Documents or otherwise communicated to Lender in writing by the Company.  Lender has not
relied on any statement or representations inconsistent with those contained in the Disclosure
Documents.  Lender has had a reasonable opportunity to ask questions of and receive answers
from the executive officers and directors of the Company, or one or more of its officers,
concerning the Company and to obtain additional information, to the extent possessed or
obtainable without unreasonable effort or expense, necessary to verify the information in the
Disclosure Documents.  All such questions have been answered to Lender’s satisfaction;

                  (b)        Lender understands that the Warrant and the Warrant Shares are being
offered and sold without registration under the Act or qualification under the California
Corporate Securities Law of 1968, or under the laws of other states, in reliance upon the
exemptions from such registration and qualification requirements for non-public offerings.
Lender acknowledges and understands that the availability of the aforesaid exemptions depends
in part upon the accuracy of certain of the representations, declarations and warranties contained
herein, which Lender hereby makes with the intent that they may be relied upon by the Company
and its officers and directors in determining Lender’s suitability to acquire  the Warrant.  Lender
understands and acknowledges that no federal, state or other agency has reviewed or endorsed
the offering of the Warrant or the Warrant Shares or made any finding or determination as to the
fairness of the offering or completeness of the information in the Disclosure Documents;

                  (c)        Lender understands that the Warrant and the Warrant Shares may not be
offered, sold, or transferred in any manner, and the Warrant may not be exercised, unless
subsequently registered under the Act, or unless there is an exemption from such registration
available for such offer, sale or transfer;

                  (d)         Lender has such knowledge and experience in financial and business
matters to enable Lender to utilize the information contained in the Disclosure Documents, or
otherwise made available to Lender to evaluate the merits and risks of an investment in the
Warrant and the Warrant Shares and to make an informed investment decision with respect
thereto.

                                              13

                  (e)        Lender is acquiring the Warrant solely for Lender’s own account and for
long-term investment purposes, and not with a view to, or for sale in connection with, any
distribution of the Warrant or Warrant Shares; and

                  (f)        Lender is an “accredited investor,” as such term is defined in Regulation D
promulgated under the Act.

         SECTION 18.    Registration Rights.

                  (a)         The Company agrees, at its expense, upon written request from the
Lender, to register under the Act, the Warrant and the Warrant Shares and to take such other
actions as may be necessary to allow the Warrant and the Warrant Shares to be freely tradable,
without restrictions, in compliance with all regulatory requirements.  A written request for
registration shall specify the quantity of the Warrant Shares intended to be sold, the plan of
distribution and the identity of the sellers, which may include the Lender and assignees of its
rights hereunder (collectively, “Selling Securities Holders”), and whether the registration shall
be pursuant to an underwritten public offering or a “shelf” registration pursuant to Rule 415 (or
similar rule that may be adopted by the Securities and Exchange Commission).  The Company
shall not be obligated to file more than two such registration statements, other than registration
statements on Form S-3.  The Company shall keep such registration statements effective for a
period of at least nine months, except that registration statements on Form S-3 shall be kept
effective for at least three years ( or such lesser period as the parties may agree, but in no event
beyond the completion of the distribution or distributions being made pursuant thereto).  The
Company shall utilize Form S-3 if it qualifies for such use.  The Company shall make all filings
required with respect to the registration statements and will use its best efforts to cause such
filings to become effective, so that the Warrant and Warrant Shares being registered shall be
registered or qualified for sale under the securities or blue sky laws of such jurisdictions as shall
be reasonably appropriate for distribution of the Warrant and Warrant Shares covered by the
registration statement.  The Company will furnish to the Selling Securities Holders such numbers
of copies of a prospectus, including a preliminary prospectus, in conformity with the
requirements of the Act and such other related documents as the Selling Securities Holders may
reasonably request in order to effect the sale of the Warrant and Warrant Shares.  To effect any
offering pursuant to a registration statement under this Section, the Company shall enter into an
agreement containing customary representations and warranties, and indemnification and
contribution provisions, all for the benefit of Selling Securities Holders, and, in the case of an
Underwritten public offering. an underwriting agreement with an investment banking firm
selected by the Lender and reasonably acceptable to the Company, containing such customary
representations and warranties, and indemnification and contribution provisions

                                     14

                  (b)        If, at any time, the Company proposes to register any of its securities
under the Act (otherwise than pursuant to paragraph 18(a) above or on a Form S-8 if such form
cannot be used for registration of the Warrant or Warrant Shares pursuant to its terms), the
Company shall, as promptly as practicable, give written notice to the Lender.  The Company
shall include in such registration statement the Warrant and any Warrant Shares proposed to be
sold by the Selling Securities Holders. Notwithstanding the foregoing, if the offering of the
Company’s securities is to be made through underwriters, the Company shall not be required to
include the Warrant and Warrant Shares if and to the extent that the managing underwriter
reasonably believes in good
faith that such inclusion would materially adversely affect such offering unless
the Selling Securities Holders agree to postpone their sales until 10 days after
the distribution is completed.

                  (c)        The Company shall pay the cost of the registration statements filed
pursuant to this Agreement, including without limitation all registration and filing fees, fees and
expenses of compliance with securities or blue sky laws (including counsel’s fees and expenses
in connection therewith), printing expenses, messenger and delivery expenses, internal expenses
of the Company, listing fees and expenses, and fees and expenses of the Company’s counsel,
independent accountants and other persons retained or employed by the Company. Selling
Securities Holders shall pay any underwriters discounts applicable to the Warrant and Warrant
Shares.

     SECTION
19.   Legends. The Warrants and Warrant Shares issued pursuant to this
Agreement shall bear an appropriate legend, conspicuously disclosing the
restrictions on exercise and transfer under Section 2.2 of this Agreement until
the same are registered for sale under the Act. The Company agrees that upon the
sale of the Warrant and Warrant Shares pursuant to a registration statement or
an exemption, upon the presentation of the certificates containing such a legend
to it’s transfer agent, it will remove such legend. The Company further
agrees to remove the legend at such time as registration under the Act shall no
longer be required. 

     SECTION
20.    Applicable Law. This Agreement and each Warrant issued hereunder
shall be governed by and construed in accordance with the laws of the State of
California, without giving effect to principles of conflict of laws. 

     SECTION
21.    Benefits of this Agreement. Nothing in this Agreement shall be
construed to give to any person or corporation other than the Company, the
Warrant Agent (if appointed) and the Holders any legal or equitable right,
remedy or claim under this Agreement; but this Agreement shall be for the sole
and exclusive benefit of the Company, the Warrant Agent and the Holders of the
Warrants. 

     SECTION
22.   Counterparts. This Agreement may be executed in any number of
counterparts and each of such counterparts shall for all purposes be deemed to
be an original, and all such counterparts shall together constitute but one and
the same instrument. 

              SECTION 23.    Captions.  The captions of the Sections and subsections of this Agreement
have been inserted for convenience only and shall have no substantive effect.

                                                 15

     IN
WITNESS WHEREOF, the parties hereto have caused this Agreement to be duly
executed, all as of the day and year first above written. 

                                             BIOTIME, INC.

                                                        By:/s/ Paul Segall          

                                                                               Name:
Paul Segall, Ph.D

                                                                     
                                          
Title: Chairman and Chief Executive Officer

Attest:

By:/s/ Judith Segall          

     Name: Judith Segall

     Title: Secretary

                                                                    /s/ Alfred D. Kingsley       

            Alfred D. Kingsley

                                                      16

                                                                                                          EXHIBIT A

                            THIS WARRANT HAS NOT BEEN REGISTERED UNDER THE SECURITIES
ACT OF 1933, AS AMENDED, OR UNDER APPLICABLE STATE SECURITIES LAWS.
THIS WARRANT MAY NOT BE EXERCISED, SOLD, PLEDGED, HYPOTHECATED,
TRANSFERRED OR ASSIGNED EXCEPT UNDER AN EFFECTIVE REGISTRATION
STATEMENT UNDER SUCH ACT AND APPLICABLE STATE SECURITIES LAWS,
UNLESS AN EXEMPTION FROM SUCH REGISTRATION IS AVAILABLE.

                                VOID AFTER 5:00 P.M. NEW YORK TIME, March 26, 2006

Certificate No.______                                                                        Warrant to Purchase
                                                                                          [Insert number of Shares]
                                                                                          -------------------------
                                                                                            Shares of Common Stock

	

                                                   BIOTIME, INC.

                                          COMMON SHARE PURCHASE WARRANTS

     This
certifies that, for value received, [Insert name of Holder] or registered
assigns (the “Holder”), is entitled to purchase from BioTime, Inc. a
California corporation (the “Company”), at a purchase price per share
[Insert Warrant Price determined pursuant to Sections 9 and 10 of the Warrant
Agreement] (the “Warrant Price”), the number of its Common Shares, no
par value per share (the “Common Stock”), shown above. The number of
shares purchasable upon exercise of the Common Share Purchase Warrants (the
“Warrants”) and the Warrant Price are subject to adjustment from time
to time as set forth in the Warrant Agreement referred to below. Outstanding
Warrants not exercised prior to 5:00 p.m., New York time, on March 26, 2006
shall thereafter be void. 

     Subject
to restriction specified in the Warrant Agreement, Warrants may be exercised in
whole or in part by presentation of this Warrant Certificate with the Purchase
Form on the reverse side hereof duly executed, which signature shall be
guaranteed by a bank or trust company or a broker or dealer which is a member of
the National Association of Securities Dealers, Inc., and simultaneous payment
of the Warrant Price (or as otherwise set forth in Section 10.5) of the Warrant
Agreement at the principal office of the Company (or if a Warrant Agent is
appointed, at the principal office of the Warrant Agent). Payment of such price
shall be made in cash or by certified or bank cashier’s check. As provided
in the Warrant Agreement, the Warrant Price and the number or kind of shares
which may be purchased upon the exercise of the Warrant evidenced by this
Warrant Certificate are, upon the happening of certain events, subject to
modification and adjustment. 

                                                 17

     This
Warrant Certificate is issued under and in accordance with a Warrant Agreement
dated as of March 27, 2001 between the Company and Alfred D. Kingsley and is
subject to the terms and provisions contained in the Warrant Agreement, to all
of which the Holder of this Warrant Certificate by acceptance of this Warrant
Certificate consents. A copy of the Warrant Agreement may be obtained by the
Holder hereof upon written request to the Company. In the event that pursuant to
Section 13 of the Warrant Agreement a Warrant Agent is appointed and a new
warrant agreement entered into between the Company and such Warrant Agent, then
such new warrant agreement shall constitute the Warrant Agreement for purposes
hereof and this Warrant Certificate shall be deemed to have been issued pursuant
to such new warrant agreement. 

     Upon
any partial exercise of the Warrant evidenced by this Warrant Certificate, there
shall be issued to the Holder hereof a new Warrant Certificate in respect of the
shares of Common Stock as to which the Warrant evidenced by this Warrant
Certificate shall not have been exercised. This Warrant Certificate may be
exchanged at the office of the Company (or the Warrant Agent, if appointed) by
surrender of this Warrant Certificate properly endorsed either separately or in
combination with one or more other Warrant Certificates for one or more new
Warrant Certificates evidencing the right of the Holder thereof to purchase the
aggregate number of shares as were purchasable on exercise of the Warrants
evidenced by the Warrant Certificate or Certificates exchanged. No fractional
shares will be issued upon the exercise of any Warrant, but the Company will pay
the cash value thereof determined as provided in the Warrant Agreement. This
Warrant Certificate is transferable at the office of the Company (or the Warrant
Agent, if appointed) in the manner and subject to the limitations set forth in
the Warrant Agreement. 

     The
Holder hereof may be treated by the Company, the Warrant Agent (if appointed)
and all other persons dealing with this Warrant Certificate as the absolute
owner hereof for any purpose and as the person entitled to exercise the rights
represented hereby, or to the transfer hereof on the books of the Company, any
notice to the contrary notwithstanding, and until such transfer on such books,
the Company (and the Warrant Agent, if appointed) may treat the Holder hereof as
the owner for all purposes. 

              Neither the Warrant nor this Warrant Certificate entitles any Holder to any of the rights
of a stockholder of the Company.

     This
Warrant Certificate shall not be valid or obligatory for any purpose until it
shall have been countersigned by the Warrant Agent.]* 

                                                    18

DATED:

                                                     BIOTIME, INC.

(Seal)                                               By:___________________________

                                                     Title:________________________

Attest:____________________

[COUNTERSIGNED:

                                    ,
WARRANT AGENT

By:_________________________]*
         Authorized Signature

--------------------
*  To be part of the Warrant only after the appointment of a Warrant Agent pursuant
   to Section 13 of the Warrant Agreement.

	

                                                    19

                                                      PURCHASE FORM

                                        (To be executed upon exercise of Warrant)

To BioTime, Inc.:

     The
undersigned hereby irrevocably elects to exercise the right of purchase
represented by the within Warrant Certificate for, and to purchase thereunder,
      shares of Common Stock, as provided for therein, and tenders herewith
payment of the purchase price in full in the form of cash or a certified or bank
cashier’s check in the amount of $      . 

     Please
issue a certificate or certificates for such shares of Common Stock in the name
of, and pay any cash for any fractional share to: 

PLEASE INSERT SOCIAL SECURITY                        NAME
OR OTHER IDENTIFYING NUMBER                          (Please Print Name & Address)
OF ASSIGNEE

                                                     Address    ___________________________

                                                     Signature  ___________________________

                                                              NOTE:       The above signature should
                                                                          correspond exactly with the name on
                                                                          the face of this Warrant Certificate or
                                                                          with the name of the assignee
                                                                          appearing in the assignment form
                                                                          below.

	
And, if said number of
shares shall not be all the shares purchasable under the within Warrant
Certificate, a new Warrant Certificate is to be issued in the name of said
undersigned for the balance remaining of the share purchasable thereunder less
any fraction of a share paid in cash. 

                                                         20

                                                       ASSIGNMENT

                              (To be executed only upon assignment of Warrant Certificate)

        For
value received,        hereby sells, assigns and transfers unto
       the within Warrant Certificate, together with all right, title
and interest therein, and does hereby irrevocably constitute and appoint
       attorney, to transfer said Warrant Certificate on the books of
the within-named Company, with full power of substitution in the premises. 

Dated:___________________                                     ________________________________
                                                              NOTE:       The above signature should
                                                                          correspond exactly with the name on
                                                                          the face of this Warrant Certificate.

	
                                                         21

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