Document:

Right to
                                                                Purchase

                                                                --------
                                                                Shares of
                                                                Common Stock,
                                                                par value $0.001
                                                                per share

                         COMMON STOCK PURCHASE WARRANT A

         THIS CERTIFIES THAT, for value received, ________________ (the
"Holder") or its registered assigns, is entitled to purchase from Geron
Corporation, a Delaware corporation (the "Company"), at any time or from time to
time during the period specified in Paragraph 2 hereof,
___________________________ (______) fully paid and nonassessable shares of the
Company's common stock, par value $0.001 per share (the "Common Stock"), at a
per share exercise price equal to the lesser of (i) 120% of the average of the
closing bid price of the Common Stock on the Principal Exchange (as defined in
that certain Securities Purchase Agreement, dated December 13, 2006, by and
among the Company and the Buyers listed on the execution page thereof (the
"Purchase Agreement")) for the five (5) Trading Day (as defined in the Purchase
Agreement) period immediately prior to the Exercise Period Start Date (as
defined below) and (ii) $12.14 (the "Exercise Price"). The term "Warrant
Shares," as used herein, refers to the shares of Common Stock purchasable
hereunder. The Warrant Shares and the Exercise Price are subject to adjustment
as provided in Paragraph 4 hereof. The term "Warrants" means this Warrant and
the other warrants (including the B Warrants and the C Warrants (each as defined
in the Purchase Agreement)) issued pursuant to the Purchase Agreement.

         This Warrant is subject to the following terms, provisions, and
conditions:

1.     Manner of Exercise; Issuance of Certificates; Payment for Warrant Shares.

        (a)      Subject to the provisions hereof, this Warrant may be exercised
by the Holder, in whole or in part, by the surrender of this Warrant, together
with a completed exercise agreement in the form attached hereto (the "Exercise
Agreement"), to the Company during normal business hours on any business day at
the Company's principal executive offices (or such other office or agency of the
Company as it may designate by notice to the Holder), and upon (i) payment to
the Company in cash, by certified or official bank check or by wire transfer for
the account of the Company of the Exercise Price for the Warrant Shares
specified in the Exercise Agreement or (ii) delivery to the Company of a written
notice of an election to effect a "Cashless Exercise" (as defined in Section
10(c) below) for the Warrant Shares specified in the Exercise Agreement. The
Warrant Shares so purchased shall be deemed to be issued to the Holder or such
holder's designee, as the record owner of such shares, as of the close of
business on the date on which this Warrant shall have been surrendered, the
completed Exercise Agreement shall have been delivered, and payment shall have
been made for such shares (or an election to effect a Cashless Exercise has been
made) as set forth above.

<PAGE>

In the event of any exercise of the rights represented by this Warrant in
accordance with and subject to the terms and conditions hereof, the Warrant
Shares shall be issued and delivered to the Depository Trust Company account
on the Holder's behalf via the Deposit Withdrawal Agent Commission system ("DWAC
Transfer") within a reasonable time, not exceeding two (2) trading days after
such exercise (or, if DWAC Transfer is not available or Holder requests in
writing otherwise, certificates for the Warrant Shares shall be issued, dated
the date of such exercise and delivered to the Holder hereof within a reasonable
time, not exceeding three (3) trading days after such exercise), and the Holder
hereof shall be deemed for all purposes to be the holder of the Warrant Shares
so purchased as of the date of such exercise. Any certificates requested shall
be delivered in such denominations as may be requested by the Holder and shall
be registered in the name of such holder or such other name as shall be
designated by such holder. If this Warrant shall have been exercised only in
part, then, unless this Warrant has expired, the Company shall, at its expense,
at the time of delivery of such certificates, deliver to the holder a new
Warrant representing the number of shares with respect to which this Warrant
shall not then have been exercised. In the event an Exercise Agreement is
delivered and the Company is unable to issue the Warrant Shares, the Holder may,
its option, rescind such Exercise Agreement and such rescission will not effect
the Holder's right to an extension of the Exercise Period pursuant to Section
4.13 of the Purchase Agreement.

        (b)      Notwithstanding anything in this Warrant to the contrary, in no
event shall the Holder of this Warrant be entitled to exercise a number of
Warrants (or portions thereof) in excess of the number of Warrants (or portions
thereof) upon exercise of which the sum of (i) the number of shares of Common
Stock beneficially owned by the Holder and its affiliates (other than shares of
Common Stock which, but for this proviso, may be deemed beneficially owned
through the ownership of the unexercised Warrants and the unexercised or
unconverted portion of any other securities of the Company subject to a
limitation on conversion or exercise analogous to the limitation contained
herein) and (ii) the number of shares of Common Stock issuable upon exercise of
the Warrants (or portions thereof) with respect to which the determination
described herein is being made, would result in beneficial ownership by the
Holder and its affiliates of more than 4.9% of the outstanding shares of Common
Stock. For purposes of the immediately preceding sentence, beneficial ownership
shall be determined in accordance with Section 13(d) of the Securities Exchange
Act of 1934, as amended, and Regulations 13D-G thereunder, except as otherwise
provided in this paragraph (b). Notwithstanding anything in this Warrant to the
contrary, the restrictions on exercise of this Warrant set forth in this
paragraph shall not be amended without (i) the written consent of the Holder and
the Company and (ii) the approval of the holders of a majority of the Common
Stock present, or represented by proxy, and voting at any meeting called to vote
on the amendment of such restriction.

2.       Period of Exercise. This Warrant is exercisable at any time or from
time to time on or after June 13, 2007 ("Exercise Period Start Date") and before
5:00 p.m., New York City time on December 15, 2010 (the "Exercise Period");
provided, however, that the Exercise Period may be extended pursuant to Section
4.13 of the Purchase Agreement.

3.       Certain Agreements of the Company. The Company hereby covenants and
agrees as follows:

                                       2
<PAGE>

        (a)      Shares to be Fully Paid. All Warrant Shares will, upon issuance
in accordance with the terms of this Warrant, be validly issued, fully paid, and
nonassessable and free from all taxes, liens, and charges with respect to the
issue thereof.

        (b)      Reservation of Shares. During the Exercise Period, the Company
shall at all times have authorized, and reserved for the purpose of issuance
upon exercise of this Warrant, a sufficient number of shares of Common Stock to
provide for the full exercise of this Warrant.

        (c)      Listing. The Company shall promptly secure the listing of the
Warrant Shares upon each national securities exchange or automated quotation
system, if any, upon which shares of Common Stock are then listed (subject to
official notice of issuance upon exercise of this Warrant) and shall maintain,
so long as any other shares of Common Stock shall be so listed, such listing of
all Warrant Shares; and the Company shall so list on each national securities
exchange or automated quotation system, as the case may be, and shall maintain
such listing of, any other shares of capital stock of the Company issuable upon
the exercise of this Warrant if and so long as any shares of the same class
shall be listed on such national securities exchange or automated quotation
system.

        (d)      Certain Actions Prohibited. The Company will not, by amendment
of its charter or through any reorganization, transfer of assets, consolidation,
merger, dissolution, issue or sale of securities, or any other voluntary action,
avoid or seek to avoid the observance or performance of any of the terms to be
observed or performed by it hereunder, but will at all times in good faith
assist in the carrying out of all the provisions of this Warrant and in the
taking of all such action as may reasonably be requested by the holder of this
Warrant in order to protect the exercise privilege of the holder of this Warrant
against dilution or other impairment, consistent with the tenor and purpose of
this Warrant. Without limiting the generality of the foregoing, the Company (i)
will not increase the par value of any shares of Common Stock receivable upon
the exercise of this Warrant above the Exercise Price then in effect, and (ii)
will take all such actions as may be necessary or appropriate in order that the
Company may validly and legally issue fully paid and nonassessable shares of
Common Stock upon the exercise of this Warrant.

        (e)      Successors and Assigns. This Warrant will be binding upon any
entity succeeding to the Company by merger, consolidation, or acquisition of all
or substantially all the Company's assets.

4.       Antidilution Provisions. During the Exercise Period, the Exercise Price
and the number of Warrant Shares shall be subject to adjustment from time to
time as provided in this Paragraph 4. In the event that any adjustment of the
Exercise Price as required herein results in a fraction of a cent, such Exercise
Price shall be rounded up to the nearest cent.

        (a)      Subdivision or Combination of Common Stock. If the Company at
any time subdivides (by any stock split, stock dividend, recapitalization,
reorganization, reclassification or otherwise) the shares of Common Stock
acquirable hereunder into a greater number of shares, then, after the date of
record for effecting such subdivision, the Exercise Price in effect immediately
prior to such subdivision will be proportionately reduced.

                                       3
<PAGE>

If the Company at any time combines (by reverse stock split, recapitalization,
reorganization, reclassification or otherwise) the shares of Common Stock
acquirable hereunder into a smaller number of shares, then, after the date of
record for effecting such combination, the Exercise Price in effect immediately
prior to such combination will be proportionately increased. "Common Stock," for
purposes of this Paragraph 4, includes the Common Stock, par value $0.001 per
share, and any additional class of stock of the Company having no preference as
to dividends or distributions on liquidation, provided that the shares
purchasable pursuant to this Warrant shall include only shares of Common Stock,
par value $0.001 per share, in respect of which this Warrant is exercisable, or
shares resulting from any subdivision or combination of such Common Stock, or in
the case of any reorganization, reclassification, consolidation, merger, or sale
of the character referred to in Paragraph 4(c) hereof, the stock or other
securities or property provided for in such Paragraph.

        (b)      Adjustment in Number of Shares. Upon each adjustment of the
Exercise Price pursuant to the provisions of this Paragraph 4, the number of
shares of Common Stock issuable upon exercise of this Warrant shall be adjusted
by multiplying a number equal to the Exercise Price in effect immediately prior
to such adjustment by the number of shares of Common Stock issuable upon
exercise of this Warrant immediately prior to such adjustment and dividing the
product so obtained by the adjusted Exercise Price.

        (c)      Consolidation, Merger or Sale. In case of any consolidation of
the Company with, or merger of the Company into any other corporation, or in
case of any sale or conveyance of all or substantially all of the assets of the
Company other than in connection with a plan of complete liquidation of the
Company, then as a condition of such consolidation, merger or sale or
conveyance, adequate provision will be made whereby the holder of this Warrant
will have the right to acquire and receive upon exercise of this Warrant in lieu
of the shares of Common Stock immediately theretofor acquirable upon the
exercise of this Warrant, such shares of stock, securities or assets as may be
issued or payable with respect to or in exchange for the number of shares of
Common Stock immediately theretofore acquirable and receivable upon exercise of
this Warrant had such consolidation, merger or sale or conveyance not taken
place. In any such case, the Company will make appropriate provision to insure
that the provisions of this Paragraph 4 hereof will thereafter be applicable as
nearly as may be in relation to any shares of stock or securities thereafter
deliverable upon the exercise of this Warrant. The Company will not effect any
consolidation, merger or sale or conveyance unless prior to the consummation
thereof, the successor or acquiring entity (if other than the Company) and, if
an entity different from the successor or acquiring entity, the entity whose
capital stock or assets the holders of the Common Stock of the Company are
entitled to receive as a result of such consolidation, merger or sale or
conveyance assumes by written instrument the obligations under this Paragraph 4
and the obligations to deliver to the holder of this Warrant such shares of
stock, securities or assets as, in accordance with the foregoing provisions, the
holder may be entitled to acquire.

        (d)      Distribution of Assets. In case the Company shall declare or
make any distribution of its assets (including cash) to holders of Common Stock
as a partial liquidating dividend, by way of return of capital or otherwise,
then, after the date of record for determining stockholders entitled to such
distribution, but prior to the date of distribution, the holder of this Warrant
shall be entitled upon exercise of this Warrant for the purchase of any or all
of the shares of Common Stock subject hereto, to receive the amount of such
assets which would have been payable to the holder had such holder been the
holder of such shares of Common Stock on the record date for the determination
of stockholders entitled to such distribution.

                                       4

<PAGE>

        (e)      Notice of Adjustment. Upon the occurrence of any event which
requires any adjustment of the Exercise Price, then, and in each such case, the
Company shall give notice thereof to the holder of this Warrant, which notice
shall state the Exercise Price resulting from such adjustment and the increase
or decrease in the number of Warrant Shares purchasable at such price upon
exercise, setting forth in reasonable detail the method of calculation and the
facts upon which such calculation is based. Such calculation shall be certified
by the chief financial officer of the Company.

        (f)      Minimum Adjustment of Exercise Price. No adjustment of the
Exercise Price shall be made in an amount of less than 1% of the Exercise Price
in effect at the time such adjustment is otherwise required to be made, but any
such lesser adjustment shall be carried forward and shall be made at the time
and together with the next subsequent adjustment which, together with any
adjustments so carried forward, shall amount to not less than 1% of such
Exercise Price.

        (g)      No Fractional Shares. No fractional shares of Common Stock are
to be issued upon the exercise of this Warrant. If the exercise of this Warrant
would result in a fractional share of Common Stock, such fractional share shall
be disregarded and the number of shares of Common Stock issuable upon exercise
of the Warrant shall be the next higher number of shares.

        (h)      Other Notices. In case at any time:

                (i)      the Company shall declare any dividend upon the Common
        Stock payable in shares of stock of any class or make any other
        distribution (including dividends or distributions payable in cash out
        of retained earnings) to the holders of the Common Stock;

                (ii)     the Company shall offer for subscription pro rata to
        the holders of the Common Stock any additional shares of stock of any
        class or other rights;

                (iii)    there shall be any capital reorganization of the
        Company, or reclassification of the Common Stock, or consolidation or
        merger of the Company with or into, or sale of all or substantially all
        its assets to, another corporation or entity; or

                (iv)     there shall be a voluntary or involuntary dissolution,
        liquidation or winding-up of the Company;

then, in each such case, the Company shall give to the holder of this Warrant
(a) notice of the date on which the books of the Company shall close or a record
shall be taken for determining the holders of Common Stock entitled to receive
any such dividend, distribution, or subscription rights or for determining the
holders of Common Stock entitled to vote in respect of any such reorganization,
reclassification, consolidation, merger, sale, dissolution, liquidation or
winding-up and (b) in the case of any such reorganization, reclassification,
consolidation, merger, sale, dissolution, liquidation or winding-up, notice of
the date (or, if not then known, a reasonable approximation thereof by the
Company) when the same shall take place.

                                       5
<PAGE>

Such notice shall also specify the date on which the holders of Common Stock
shall be entitled to receive such dividend, distribution, or subscription rights
or to exchange their Common Stock for stock or other securities or property
deliverable upon such reorganization, reclassification, consolidation, merger,
sale, dissolution, liquidation, or winding-up, as the case may be. Such notice
shall be given at least 15 days prior to the record date or the date on which
the Company's books are closed in respect thereto. Failure to give any such
notice or any defect therein shall not affect the validity of the proceedings
referred to in clauses (i), (ii), (iii) and (iv) above.

        (i) Certain Events. If any event occurs of the type contemplated by the
adjustment provisions of this Paragraph 4 but not expressly provided for by such
provisions, the Company will give notice of such event as provided in Paragraph
4(e) hereof, and the Company's Board of Directors will make an appropriate
adjustment in the Exercise Price and the number of shares of Common Stock
acquirable upon exercise of this Warrant so that the rights of the Holder shall
be neither enhanced nor diminished by such event.

        (j) Withholding Taxes. In the event that an adjustment to the Exercise
Price (or a failure to adjust the Exercise Price) results in a constructive
distribution to the Holder of the Warrants under Section 305 of the Internal
Revenue Code of 1986, as amended, the Company may withhold, to the extent
required by applicable law, any applicable United States federal withholding tax
from any subsequent distributions of cash or property made to the Holder,
including any Common Stock issued by the Company upon the exercise of this
Warrant.

5.       Issue Tax. The issuance of certificates for Warrant Shares upon the
exercise of this Warrant shall be made without charge to the holder of this
Warrant or such shares for any issuance tax or other costs in respect thereof,
provided that the Company shall not be required to pay any tax which may be
payable in respect of any transfer involved in the issuance and delivery of any
certificate in a name other than the holder of this Warrant.

6.       No Rights or Liabilities as a Stockholder. This Warrant shall not
entitle the Holder to any voting rights or other rights as a stockholder of the
Company. No provision of this Warrant, in the absence of affirmative action by
the Holder to purchase Warrant Shares, and no mere enumeration herein of the
rights or privileges of the Holder, shall give rise to any liability of such
holder for the Exercise Price or as a stockholder of the Company, whether such
liability is asserted by the Company or by creditors of the Company.

7. Transfer, Exchange, and Replacement of Warrant.

        (a) Transfer. This Warrant and the rights granted to the Holder are
transferable, in whole or in part, upon surrender of this Warrant, together with
a properly executed assignment in the form attached hereto, at the office or
agency of the Company referred to in Paragraph 7(e) below. Until due presentment
for registration of transfer on the books of the Company, the Company may treat
the registered Holder as the owner and Holder for all purposes, and the Company
shall not be affected by any notice to the contrary.

        (b) Warrant Exchangeable for Different Denominations. This Warrant is
exchangeable, upon the surrender hereof by the Holder at the office or agency of
the Company referred to in Paragraph 7(e) below, for new Warrants of like tenor
representing in the aggregate the right to purchase the number of shares of
Common Stock which may be purchased hereunder, each of such new Warrants to
represent the right to purchase such number of shares as shall be designated by
the Holder at the time of such surrender.

                                       6
<PAGE>

        (c) Replacement of Warrant. Upon receipt of evidence reasonably
satisfactory to the Company of the loss, theft, destruction, or mutilation of
this Warrant and, in the case of any such loss, theft, or destruction, upon
delivery of an indemnity agreement reasonably satisfactory in form and amount
to the Company, or, in the case of any such mutilation, upon surrender and
cancellation of this Warrant, the Company, at its expense, will execute and
deliver, in lieu thereof, a new Warrant of like tenor.

        (d) Cancellation; Payment of Expenses. Upon the surrender of this
Warrant in connection with any transfer, exchange, or replacement as provided in
this Paragraph 7, this Warrant shall be promptly canceled by the Company. The
Company shall pay all taxes (other than securities transfer taxes) and all other
expenses (other than legal expenses, if any, incurred by the Holder or
transferees) and charges payable in connection with the preparation, execution,
and delivery of Warrants pursuant to this Paragraph 7.

        (e) Register. The Company shall maintain, at its principal executive
offices (or such other office or agency of the Company as it may designate by
notice to the Holder), a register for this Warrant, in which the Company shall
record the name and address of the person in whose name this Warrant has been
issued, as well as the name and address of each transferee and each prior owner
of this Warrant.

8.       Notices. All notices, requests, and other communications required or
permitted to be given or delivered hereunder to the holder of this Warrant shall
be in writing, and shall be personally delivered, or shall be sent by certified
or registered mail or by recognized overnight mail courier, postage prepaid and
addressed, to such holder at the address shown for such holder on the books of
the Company, or at such other address as shall have been furnished to the
Company by notice from such holder. All notices, requests, and other
communications required or permitted to be given or delivered hereunder to the
Company shall be in writing, and shall be personally delivered, or shall be sent
by certified or registered mail or by recognized overnight mail courier, postage
prepaid and addressed, to the office of the Company at 230 Constitution Drive,
Menlo Park, California 94025, Attn: David Greenwood, fax no. (650) 473-7701 with
copies to Latham & Watkins LLP, 140 Scott Drive, Menlo Park, California 94025,
Attn: Alan C. Mendelson, Esq., fax no. (650) 463-2600, or at such other address
as shall have been furnished to the holder of this Warrant by notice from the
Company. Any such notice, request, or other communication may be sent by
facsimile, but shall in such case be subsequently confirmed by a writing
personally delivered or sent by certified or registered mail or by recognized
overnight mail courier as provided above. All notices, requests, and other
communications shall be deemed to have been given either at the time of the
receipt thereof by the person entitled to receive such notice at the address of
such person for purposes of this Paragraph 8, or, if mailed by registered or
certified mail or with a recognized overnight mail courier upon deposit with the
United States Post Office or such overnight mail courier, if postage is prepaid
and the mailing is properly addressed, as the case may be.

                                       7
<PAGE>

9.       Governing Law. THIS WARRANT SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF DELAWARE APPLICABLE TO AGREEMENTS MADE
AND TO BE PERFORMED IN THE STATE OF DELAWARE (WITHOUT REGARD TO PRINCIPLES OF
CONFLICT OF LAWS). BOTH PARTIES IRREVOCABLY CONSENT TO THE EXCLUSIVE
JURISDICTION OF THE UNITED STATES FEDERAL COURTS AND THE STATE COURTS LOCATED IN
DELAWARE WITH RESPECT TO ANY SUIT OR PROCEEDING BASED ON OR ARISING UNDER THIS
AGREEMENT, THE AGREEMENTS ENTERED INTO IN CONNECTION HEREWITH OR THE
TRANSACTIONS CONTEMPLATED HEREBY OR THEREBY AND IRREVOCABLY AGREE THAT ALL
CLAIMS IN RESPECT OF SUCH SUIT OR PROCEEDING MAY BE DETERMINED IN SUCH COURTS.
BOTH PARTIES IRREVOCABLY WAIVE THE DEFENSE OF AN INCONVENIENT FORUM TO THE
MAINTENANCE OF SUCH SUIT OR PROCEEDING. BOTH PARTIES FURTHER AGREE THAT SERVICE
OF PROCESS UPON A PARTY MAILED BY FIRST CLASS MAIL SHALL BE DEEMED IN EVERY
RESPECT EFFECTIVE SERVICE OF PROCESS UPON THE PARTY IN ANY SUCH SUIT OR
PROCEEDING. NOTHING HEREIN SHALL AFFECT EITHER PARTY'S RIGHT TO SERVE PROCESS IN
ANY OTHER MANNER PERMITTED BY LAW. BOTH PARTIES AGREE THAT A FINAL
NON-APPEALABLE JUDGMENT IN ANY SUCH SUIT OR PROCEEDING SHALL BE CONCLUSIVE AND
MAY BE ENFORCED IN OTHER JURISDICTIONS BY SUIT ON SUCH JUDGMENT OR IN ANY OTHER
LAWFUL MANNER.

10. Miscellaneous.

        (a) Amendments. This Warrant and any provision hereof may only be
amended by an instrument in writing signed by the Company and the Holder.

        (b) Descriptive Headings. The descriptive headings of the several
paragraphs of this Warrant are inserted for purposes of reference only, and
shall not affect the meaning or construction of any of the provisions hereof.

        (c) Cashless Exercise. This Warrant may be exercised by presentation and
surrender of this Warrant to the Company at its principal executive offices with
a written notice of the holder's intention to effect a cashless exercise,
including a calculation of the number of shares of Common Stock to be issued
upon such exercise in accordance with the terms hereof (a "Cashless Exercise").
In the event of a Cashless Exercise, the Holder shall be entitled to receive a
certificate for the number of Warrant Shares equal to the quotient obtained by
dividing [(A-B) (X)] by (A), where:

        (A) = the closing price on the trading day immediately preceding the
              date of such election;

        (B) = the Exercise Price of this Warrant, as adjusted; and

        (X) = the number of Warrant Shares issuable upon exercise of this
Warrant in accordance with the terms of this Warrant by means of a cash exercise
rather than a cashless exercise.

                                       8
<PAGE>

        (d) Remedies. The Company acknowledges that a breach by it of its
obligations hereunder will cause irreparable harm to the holder of this Warrant
by vitiating the intent and purpose of the transactions contemplated hereby.
Accordingly, the Company acknowledges that the remedy at law for a breach of its
obligations under this Warrant will be inadequate and agrees, in the event of a
breach or threatened breach by the Company of the provisions of this Warrant,
that the holder of this Warrant shall be entitled, in addition to all other
available remedies in law or in equity, to an injunction or injunctions to
prevent or cure any breaches of the provisions of this Agreement and to enforce
specifically the terms and provisions of this Warrant, without the necessity of
showing economic loss and without any bond or other security being required.

                [REMAINDER OF THIS PAGE INTENTIONALLY LEFT BLANK]

                                       9
<PAGE>

         IN WITNESS WHEREOF, the Company has caused this Warrant to be signed by
its duly authorized officer.

                                          GERON CORPORATION

                                           By:
                                              ----------------------------------
                                           Name:    David L. Greenwood
                                           Title:   Executive Vice President and
                                                    Chief Financial Officer

                                            Dated as of December 15, 2006

                                       10
<PAGE>

                           FORM OF EXERCISE AGREEMENT

                                                      Dated:  ________ __, 200_

To:  GERON CORPORATION

         The undersigned, pursuant to the provisions set forth in the Warrant
attached hereto, hereby agrees to purchase ________ shares of Common Stock
covered by such Warrant, and makes payment herewith in full therefor at the
price per share provided by such Warrant in cash or by certified or official
bank check in the amount of, or by surrender of securities issued by the Company
(including a portion of the Warrant) having a market value (in the case of a
portion of this Warrant, determined in accordance with Section 10(c) of the
Warrant) equal to $_________. 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:

                                    Name:
                                         ---------------------------------------

                                    Signature:
                                         ---------------------------------------

                                    Address:
                                            ------------------------------------
                                    --------------------------------------------
                                    --------------------------------------------

                                    Note:    The above signature  should
                                             correspond  exactly with the name
                                             on the face of the Warrant
                                             attached hereto.

and, if said number of shares of Common Stock shall not be all the shares
purchasable under the Warrant attached hereto, a new Warrant is to be issued in
the name of said undersigned covering the balance of the shares purchasable
thereunder less any fraction of a share paid in cash.

<PAGE>

                               FORM OF ASSIGNMENT

         FOR VALUE RECEIVED, the undersigned hereby sells, assigns, and
transfers all the rights of the undersigned under the Warrant attached hereto,
with respect to the number of shares of Common Stock covered thereby set forth
hereinbelow, to:

Name of Assignee              Address                 No of Shares
----------------              -------                 ------------

, and hereby irrevocably constitutes and appoints_______________________________
as agent and attorney-in-fact to transfer said Warrant on the books of the
within-named corporation, with full power of substitution in the premises.

Dated:  ________ __, 200_

In the presence of:

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

                                     Name:
                                          -------------------------------------

                                     Signature:
                                          -------------------------------------

                                     Title of Signing Officer or Agent (if any):

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

                                     Address:
                                            ------------------------------------
                                     -------------------------------------------

                                     Note: The above signature should correspond
                                     exactly with the name on the face of the
                                     Warrant attached hereto.Right to
                                                         Purchase _______
                                                         Shares of Common Stock,
                                                         par value $0.001
                                                         per share

                         COMMON STOCK PURCHASE WARRANT B

         THIS CERTIFIES THAT, for value received, ________________ (the
"Holder") or its registered assigns, is entitled to purchase from Geron
Corporation, a Delaware corporation (the "Company"), at any time or from time to
time during the period specified in Paragraph 2 hereof,
__________________________ (______) fully paid and nonassessable shares of the
Company's common stock, par value $0.001 per share (the "Common Stock"), at an
exercise price of $8.00 per share (the "Exercise Price"). The term "Warrant
Shares," as used herein, refers to the shares of Common Stock purchasable
hereunder. The Warrant Shares and the Exercise Price are subject to adjustment
as provided in Paragraph 4 hereof. The term "Warrants" means this Warrant and
the other warrants (including the A Warrants and the C Warrants (each as defined
in the Purchase Agreement)) issued pursuant to that certain Securities Purchase
Agreement, dated December 13, 2006, by and among the Company and the Buyers
listed on the execution page thereof (the "Purchase Agreement").

         This Warrant is subject to the following terms, provisions, and
conditions:

1.       Manner of Exercise; Issuance of Certificates; Payment for Warrant
Shares.

        (a) Subject to the provisions hereof, this Warrant may be exercised by
the Holder, in whole or in part, by the surrender of this Warrant, together with
a completed exercise agreement in the form attached hereto (the "Exercise
Agreement"), to the Company during normal business hours on any business day at
the Company's principal executive offices (or such other office or agency of the
Company as it may designate by notice to the Holder), and upon payment to the
Company in cash, by certified or official bank check or by wire transfer for the
account of the Company of the Exercise Price for the Warrant Shares specified in
the Exercise Agreement. The Warrant Shares so purchased shall be deemed to be
issued to the Holder or such holder's designee, as the record owner of such
shares, as of the close of business on the date on which this Warrant shall have
been surrendered, the completed Exercise Agreement shall have been delivered,
and payment shall have been made for such shares as set forth above. In the
event of any exercise of the rights represented by this Warrant in accordance
with and subject to the terms and conditions hereof, the Warrant Shares shall be
issued and delivered to the Depository Trust Company account on the Holder's
behalf via the Deposit Withdrawal Agent Commission system ("DWAC Transfer")
within a reasonable time, not exceeding two (2) trading days after such exercise
(or, if DWAC Transfer is not available or Holder requests in writing otherwise,
certificates for the Warrant Shares shall be issued, dated the date of such
exercise and delivered to the Holder hereof within a reasonable time, not
exceeding three (3) trading days after such exercise), and the Holder hereof
shall be deemed for all purposes to be the holder of the Warrant Shares so
purchased as of the date of such exercise.

<PAGE>

Any certificates requested shall be delivered in such denominations as may be
requested by the Holder and shall be registered in the name of such holder or
such other name as shall be designated by such holder. If this Warrant shall
have been exercised only in part, then, unless this Warrant has expired, the
Company shall, at its expense, at the time of delivery of such certificates,
deliver to the holder a new Warrant representing the number of shares with
respect to which this Warrant shall not then have been exercised. In the event
an Exercise Agreement is delivered and the Company is unable to issue the
Warrant Shares, the Holder may, its option, rescind such Exercise Agreement and
such rescission will not effect the Holder's right to an extension of the
Exercise Period pursuant to Section 4.13 of the Purchase Agreement.

        (b) Notwithstanding anything in this Warrant to the contrary, in no
event shall the Holder of this Warrant be entitled to exercise a number of
Warrants (or portions thereof) in excess of the number of Warrants (or portions
thereof) upon exercise of which the sum of (i) the number of shares of Common
Stock beneficially owned by the Holder and its affiliates (other than shares of
Common Stock which, but for this proviso, may be deemed beneficially owned
through the ownership of the unexercised Warrants and the unexercised or
unconverted portion of any other securities of the Company subject to a
limitation on conversion or exercise analogous to the limitation contained
herein) and (ii) the number of shares of Common Stock issuable upon exercise of
the Warrants (or portions thereof) with respect to which the determination
described herein is being made, would result in beneficial ownership by the
Holder and its affiliates of more than 4.9% of the outstanding shares of Common
Stock. For purposes of the immediately preceding sentence, beneficial ownership
shall be determined in accordance with Section 13(d) of the Securities Exchange
Act of 1934, as amended, and Regulations 13D-G thereunder, except as otherwise
provided in clause (i) hereof. Notwithstanding anything in this Warrant to the
contrary, the restrictions on exercise of this Warrant set forth in this
paragraph shall not be amended without (i) the written consent of the Holder and
the Company and (ii) the approval of the holders of a majority of the Common
Stock present, or represented by proxy, and voting at any meeting called to vote
on the amendment of such restriction.

2.       Period of Exercise. This Warrant is exercisable at any time or from
time to time on or after the date on which this Warrant is issued and delivered
pursuant to the terms of the Purchase Agreement (the "Issue Date") and before
5:00 p.m., New York City time on February 28, 2007 (the "Exercise Period");
provided, however, that:

        (i) On February 28, 2007, if the Holder pays an extension fee of $7.99
per share (the "Extension Fee"), to the Company in cash, by certified or
official bank check or by wire transfer for the account of the Company (which
Extension Fee is non-refundable), the "Exercise Period" shall be extended to
December 15, 2009 with respect to that number of Warrant Shares determined by
dividing (i) the aggregate amount of the Extension Fee paid by (ii) $7.99;
provided, further, that after February 28, 2007, if the Exercise Period has been
extended pursuant to the terms of this Section 2 upon payment of the Extension
Fee to the Company, the Exercise Price per share shall equal $0.01; and

        (ii) the Exercise Period will be extended in accordance with Section
4.13 of the Purchase Agreement upon the occurrence of events set forth in such
section.

                                       2
<PAGE>

3.       Certain Agreements of the Company. The Company hereby covenants and
agrees as follows:

        (a)      Shares to be Fully Paid. All Warrant Shares will, upon issuance
in accordance with the terms of this Warrant, be validly issued, fully paid, and
nonassessable and free from all taxes, liens, and charges with respect to the
issue thereof.

        (b)      Reservation of Shares. During the Exercise Period, the Company
shall at all times have authorized, and reserved for the purpose of issuance
upon exercise of this Warrant, a sufficient number of shares of Common Stock to
provide for the full exercise of this Warrant.

        (c)      Listing. The Company shall promptly secure the listing of the
Warrant Shares upon each national securities exchange or automated quotation
system, if any, upon which shares of Common Stock are then listed (subject to
official notice of issuance upon exercise of this Warrant) and shall maintain,
so long as any other shares of Common Stock shall be so listed, such listing of
all Warrant Shares; and the Company shall so list on each national securities
exchange or automated quotation system, as the case may be, and shall maintain
such listing of, any other shares of capital stock of the Company issuable upon
the exercise of this Warrant if and so long as any shares of the same class
shall be listed on such national securities exchange or automated quotation
system.

        (d)      Certain Actions Prohibited. The Company will not, by amendment
of its charter or through any reorganization, transfer of assets, consolidation,
merger, dissolution, issue or sale of securities, or any other voluntary action,
avoid or seek to avoid the observance or performance of any of the terms to be
observed or performed by it hereunder, but will at all times in good faith
assist in the carrying out of all the provisions of this Warrant and in the
taking of all such action as may reasonably be requested by the holder of this
Warrant in order to protect the exercise privilege of the holder of this Warrant
against dilution or other impairment, consistent with the tenor and purpose of
this Warrant. Without limiting the generality of the foregoing, the Company (i)
will not increase the par value of any shares of Common Stock receivable upon
the exercise of this Warrant above the Exercise Price then in effect, and (ii)
will take all such actions as may be necessary or appropriate in order that the
Company may validly and legally issue fully paid and nonassessable shares of
Common Stock upon the exercise of this Warrant.

        (e)      Successors and Assigns. This Warrant will be binding upon any
entity succeeding to the Company by merger, consolidation, or acquisition of
all or substantially all the Company's assets.

4.       Antidilution Provisions. During the Exercise Period, the Exercise Price
and the number of Warrant Shares shall be subject to adjustment from time to
time as provided in this Paragraph 4. In the event that any adjustment of the
Exercise Price as required herein results in a fraction of a cent, such Exercise
Price shall be rounded up to the nearest cent.

                                       3
<PAGE>

        (a)      Subdivision or Combination of Common Stock. If the Company at
any time subdivides (by any stock split, stock dividend, recapitalization,
reorganization, reclassification or otherwise) the shares of Common Stock
acquirable hereunder into a greater number of shares, then, after the date of
record for effecting such subdivision, the Exercise Price in effect immediately
prior to such subdivision will be proportionately reduced. If the Company at any
time combines (by reverse stock split, recapitalization, reorganization,
reclassification or otherwise) the shares of Common Stock acquirable hereunder
into a smaller number of shares, then, after the date of record for effecting
such combination, the Exercise Price in effect immediately prior to such
combination will be proportionately increased. "Common Stock," for purposes of
this Paragraph 4, includes the Common Stock and any additional class of stock of
the Company having no preference as to dividends or distributions on
liquidation, provided that the shares purchasable pursuant to this Warrant shall
include only shares of Common Stock, par value $0.001 per share, in respect of
which this Warrant is exercisable, or shares resulting from any subdivision or
combination of such Common Stock, or in the case of any reorganization,
reclassification, consolidation, merger, or sale of the character referred to in
Paragraph 4(c) hereof, the stock or other securities or property provided for in
such Paragraph.

        (b)      Adjustment in Number of Shares. Upon each adjustment of the
Exercise Price pursuant to the provisions of this Paragraph 4, the number of
shares of Common Stock issuable upon exercise of this Warrant shall be
adjusted by multiplying a number equal to the Exercise Price in effect
immediately prior to such adjustment by the number of shares of Common Stock
issuable upon exercise of this Warrant immediately prior to such adjustment and
dividing the product so obtained by the adjusted Exercise Price.

        (c)      Consolidation, Merger or Sale. In case of any consolidation of
the Company with, or merger of the Company into any other corporation, or in
case of any sale or conveyance of all or substantially all of the assets of the
Company other than in connection with a plan of complete liquidation of the
Company, then as a condition of such consolidation, merger or sale or
conveyance, adequate provision will be made whereby the holder of this Warrant
will have the right to acquire and receive upon exercise of this Warrant in lieu
of the shares of Common Stock immediately theretofor acquirable upon the
exercise of this Warrant, such shares of stock, securities or assets as may be
issued or payable with respect to or in exchange for the number of shares of
Common Stock immediately theretofore acquirable and receivable upon exercise of
this Warrant had such consolidation, merger or sale or conveyance not taken
place. In any such case, the Company will make appropriate provision to insure
that the provisions of this Paragraph 4 hereof will thereafter be applicable as
nearly as may be in relation to any shares of stock or securities thereafter
deliverable upon the exercise of this Warrant. The Company will not effect any
consolidation, merger or sale or conveyance unless prior to the consummation
thereof, the successor or acquiring entity (if other than the Company) and, if
an entity different from the successor or acquiring entity, the entity whose
capital stock or assets the holders of the Common Stock of the Company are
entitled to receive as a result of such consolidation, merger or sale or
conveyance assumes by written instrument the obligations under this Paragraph 4
and the obligations to deliver to the holder of this Warrant such shares of
stock, securities or assets as, in accordance with the foregoing provisions, the
holder may be entitled to acquire.

        (d)      Distribution of Assets. In case the Company shall declare or
make any distribution of its assets (including cash) to holders of Common Stock
as a partial liquidating dividend, by way of return of capital or otherwise,
then, after the date of record for determining stockholders entitled to such
distribution, but prior to the date of distribution, the holder of this Warrant
shall be entitled upon exercise of this Warrant for the purchase of any or all
of the shares of Common Stock subject hereto, to receive the amount of such
assets which would have been payable to the holder had such holder been the
holder of such shares of Common Stock on the record date for the determination
of stockholders entitled to such distribution.

                                       4
<PAGE>

        (e)      Notice of Adjustment. Upon the occurrence of any event which
requires any adjustment of the Exercise Price, then, and in each such case, the
Company  shall give notice thereof to the holder of this Warrant, which notice
shall  state the Exercise Price resulting from such adjustment and the increase
or decrease in the number of Warrant Shares purchasable at such price upon
exercise, setting forth in reasonable detail the method of calculation and the
facts upon which such calculation is based. Such calculation shall be certified
by the chief financial officer of the Company.

        (f)      Minimum Adjustment of Exercise Price. No adjustment of the
Exercise Price shall be made in an amount of less than 1% of the Exercise Price
in effect at the time such adjustment is otherwise required to be made, but any
such lesser adjustment shall be carried forward and shall be made at the time
and together with the next subsequent adjustment which, together with any
adjustments so carried forward, shall amount to not less than 1% of such
Exercise Price.

        (g)      No Fractional Shares. No fractional shares of Common Stock are
to be issued upon the exercise of this Warrant. If the exercise of this Warrant
would result in a fractional share of Common Stock, such fractional share shall
be disregarded and the number of shares of Common Stock issuable upon exercise
of the Warrant shall be the next higher number of shares.

        (h)      Other Notices. In case at any time:

                (i)      the Company shall declare any dividend upon the Common
        Stock payable in shares of stock of any class or make any other
        distribution (including dividends or distributions payable in cash out
        of retained earnings) to the holders of the Common Stock;

                (ii)     the Company shall offer for subscription pro rata to
        the holders of the Common Stock any additional shares of stock of any
        class or other rights;

                (iii)    there shall be any capital reorganization of the
        Company, or reclassification of the Common Stock, or consolidation or
        merger of the Company with or into, or sale of all or substantially all
        its assets to, another corporation or entity; or

                (iv)     there shall be a voluntary or involuntary dissolution,
        liquidation or winding-up of the Company;

then, in each such case, the Company shall give to the holder of this Warrant
(a) notice of the date on which the books of the Company shall close or a record
shall be taken for determining the holders of Common Stock entitled to receive
any such dividend, distribution, or subscription rights or for determining the
holders of Common Stock entitled to vote in respect of any such reorganization,
reclassification, consolidation, merger, sale, dissolution, liquidation or
winding-up and (b) in the case of any such reorganization, reclassification,
consolidation, merger, sale, dissolution, liquidation or winding-up, notice of
the date (or, if not then known, a reasonable approximation thereof by the
Company) when the same shall take place.

                                       5
<PAGE>

Such notice shall also specify the date on which the holders of Common Stock
shall be entitled to receive such dividend, distribution, or subscription rights
or to exchange their Common Stock for stock or other securities or property
deliverable upon such reorganization, reclassification, consolidation, merger,
sale, dissolution, liquidation, or winding-up, as the case may be. Such notice
shall be given at least 30 days prior to the record date or the date on which
the Company's books are closed in respect thereto. Failure to give any such
notice or any defect therein shall not affect the validity of the proceedings
referred to in clauses (i), (ii), (iii) and (iv) above.

                (i) Certain Events. If any event occurs of the type contemplated
by the adjustment provisions of this Paragraph 4 but not expressly provided for
by such provisions, the Company will give notice of such event as provided in
Paragraph 4(e) hereof, and the Company's Board of Directors will make an
appropriate adjustment in the Exercise Price and the number of shares of Common
Stock acquirable upon exercise of this Warrant so that the rights of the Holder
shall be neither enhanced nor diminished by such event.

                (j) Withholding Taxes. In the event that an adjustment to the
Exercise Price (or a failure to adjust the Exercise Price) results in a
constructive distribution to the Holder of the Warrants under Section 305 of the
Internal Revenue Code of 1986, as amended, the Company may withhold, to the
extent required by applicable law, any applicable United States federal
withholding tax from any subsequent distributions of cash or property made to
the Holder, including any Common Stock issued by the Company upon the exercise
of this Warrant.

5.       Issue Tax. The issuance of certificates for Warrant Shares upon the
exercise of this Warrant shall be made without charge to the holder of this
Warrant or such shares for any issuance tax or other costs in respect thereof,
provided that the Company shall not be required to pay any tax which may be
payable in respect of any transfer involved in the issuance and delivery of any
certificate in a name other than the holder of this Warrant.

6.       No Rights or Liabilities as a Stockholder. This Warrant shall not
entitle the Holder to any voting rights, dividend rights or other rights as a
stockholder of the Company. No provision of this Warrant, in the absence of
affirmative action by the Holder to purchase Warrant Shares, and no mere
enumeration herein of the rights or privileges of the Holder, shall give rise to
any liability of such holder for the Exercise Price or as a stockholder of the
Company, whether such liability is asserted by the Company or by creditors of
the Company.

7.       Transfer, Exchange, and Replacement of Warrant.

        (a) Transfer. This Warrant and the rights granted to the Holder are
transferable, in whole or in part, upon surrender of this Warrant, together with
a properly executed assignment in the form attached hereto, at the office or
agency of the Company referred to in Paragraph 7(e) below. Until due presentment
for registration of transfer on the books of the Company, the Company may treat
the registered Holder as the owner and Holder for all purposes, and the Company
shall not be affected by any notice to the contrary.

                                       6
<PAGE>

        (b) Warrant Exchangeable for Different Denominations. This Warrant is
exchangeable, upon the surrender hereof by the Holder at the office or agency of
the Company referred to in Paragraph 7(e) below, for new Warrants of like tenor
representing in the aggregate the right to purchase the number of shares of
Common Stock which may be purchased hereunder, each of such new Warrants to
represent the right to purchase such number of shares as shall be designated by
the Holder at the time of such surrender.

        (c) Replacement of Warrant. Upon receipt of evidence reasonably
satisfactory to the Company of the loss, theft, destruction, or mutilation of
this Warrant and, in the case of any such loss, theft, or destruction, upon
delivery of an indemnity agreement reasonably satisfactory in form and amount to
the Company, or, in the case of any such mutilation, upon surrender and
cancellation of this Warrant, the Company, at its expense, will execute and
deliver, in lieu thereof, a new Warrant of like tenor.

        (d) Cancellation; Payment of Expenses. Upon the surrender of this
Warrant in connection with any transfer, exchange, or replacement as provided in
this Paragraph 7, this Warrant shall be promptly canceled by the Company. The
Company shall pay all taxes (other than securities transfer taxes) and all other
expenses (other than legal expenses, if any, incurred by the Holder or
transferees) and charges payable in connection with the preparation, execution,
and delivery of Warrants pursuant to this Paragraph 7.

        (e) Register. The Company shall maintain, at its principal executive
offices (or such other office or agency of the Company as it may designate by
notice to the Holder), a register for this Warrant, in which the Company shall
record the name and address of the person in whose name this Warrant has been
issued, as well as the name and address of each transferee and each prior owner
of this Warrant.

8.       Notices. All notices, requests, and other communications required or
permitted to be given or delivered hereunder to the holder of this Warrant shall
be in writing, and shall be personally delivered, or shall be sent by certified
or registered mail or by recognized overnight mail courier, postage prepaid and
addressed, to such holder at the address shown for such holder on the books of
the Company, or at such other address as shall have been furnished to the
Company by notice from such holder. All notices, requests, and other
communications required or permitted to be given or delivered hereunder to the
Company shall be in writing, and shall be personally delivered, or shall be sent
by certified or registered mail or by recognized overnight mail courier, postage
prepaid and addressed, to the office of the Company at 230 Constitution Drive,
Menlo Park, California 94025, Attn: David Greenwood, fax no. (650) 473-7701 with
copies to Latham & Watkins LLP, 140 Scott Drive, Menlo Park, California 94025,
Attn: Alan C. Mendelson, Esq., fax no. (650) 463-2600, or at such other address
as shall have been furnished to the holder of this Warrant by notice from the
Company. Any such notice, request, or other communication may be sent by
facsimile, but shall in such case be subsequently confirmed by a writing
personally delivered or sent by certified or registered mail or by recognized
overnight mail courier as provided above. All notices, requests, and other
communications shall be deemed to have been given either at the time of the
receipt thereof by the person entitled to receive such notice at the address of
such person for purposes of this Paragraph 8, or, if mailed by registered or
certified mail or with a recognized overnight mail courier upon deposit with the
United States Post Office or such overnight mail courier, if postage is prepaid
and the mailing is properly addressed, as the case may be.

                                       7
<PAGE>

9.       Governing Law. THIS WARRANT SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF DELAWARE APPLICABLE TO AGREEMENTS MADE
AND TO BE PERFORMED IN THE STATE OF DELAWARE (WITHOUT REGARD TO PRINCIPLES OF
CONFLICT OF LAWS). BOTH PARTIES IRREVOCABLY CONSENT TO THE EXCLUSIVE
JURISDICTION OF THE UNITED STATES FEDERAL COURTS AND THE STATE COURTS LOCATED IN
DELAWARE WITH RESPECT TO ANY SUIT OR PROCEEDING BASED ON OR ARISING UNDER THIS
AGREEMENT, THE AGREEMENTS ENTERED INTO IN CONNECTION HEREWITH OR THE
TRANSACTIONS CONTEMPLATED HEREBY OR THEREBY AND IRREVOCABLY AGREE THAT ALL
CLAIMS IN RESPECT OF SUCH SUIT OR PROCEEDING MAY BE DETERMINED IN SUCH COURTS.
BOTH PARTIES IRREVOCABLY WAIVE THE DEFENSE OF AN INCONVENIENT FORUM TO THE
MAINTENANCE OF SUCH SUIT OR PROCEEDING. BOTH PARTIES FURTHER AGREE THAT SERVICE
OF PROCESS UPON A PARTY MAILED BY FIRST CLASS MAIL SHALL BE DEEMED IN EVERY
RESPECT EFFECTIVE SERVICE OF PROCESS UPON THE PARTY IN ANY SUCH SUIT OR
PROCEEDING. NOTHING HEREIN SHALL AFFECT EITHER PARTY'S RIGHT TO SERVE PROCESS IN
ANY OTHER MANNER PERMITTED BY LAW. BOTH PARTIES AGREE THAT A FINAL
NON-APPEALABLE JUDGMENT IN ANY SUCH SUIT OR PROCEEDING SHALL BE CONCLUSIVE AND
MAY BE ENFORCED IN OTHER JURISDICTIONS BY SUIT ON SUCH JUDGMENT OR IN ANY OTHER
LAWFUL MANNER.

10. Miscellaneous.

        (a) Amendments. This Warrant and any provision hereof may only be
amended by an instrument in writing signed by the Company and the Holder.

        (b) Descriptive Headings. The descriptive headings of the several
paragraphs of this Warrant are inserted for purposes of reference only, and
shall not affect the meaning or construction of any of the provisions hereof.

        (c) Remedies. The Company acknowledges that a breach by it of its
obligations hereunder will cause irreparable harm to the holder of this Warrant
by vitiating the intent and purpose of the transactions contemplated hereby.
Accordingly, the Company acknowledges that the remedy at law for a breach of its
obligations under this Warrant will be inadequate and agrees, in the event of a
breach or threatened breach by the Company of the provisions of this Warrant,
that the holder of this Warrant shall be entitled, in addition to all other
available remedies in law or in equity, to an injunction or injunctions to
prevent or cure any breaches of the provisions of this Agreement and to enforce
specifically the terms and provisions of this Warrant, without the necessity of
showing economic loss and without any bond or other security being required.

                [REMAINDER OF THIS PAGE INTENTIONALLY LEFT BLANK]

                                       8
<PAGE>

         IN WITNESS WHEREOF, the Company has caused this Warrant to be signed by
its duly authorized officer.

                                           GERON CORPORATION

                                           By:
                                              ----------------------------------
                                           Name:    David L. Greenwood
                                           Title:   Executive Vice President and
                                                    Chief Financial Officer

                                           Dated as of December 15, 2006

                                       9
<PAGE>

                           FORM OF EXERCISE AGREEMENT

                                                     Dated:  ________ __, 200_

To:  GERON CORPORATION

         The undersigned, pursuant to the provisions set forth in the Warrant
attached hereto, hereby agrees to purchase ________ shares of Common Stock
covered by such Warrant, and makes payment herewith in full therefor at the
price per share provided by such Warrant in cash or by certified or official
bank 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:

                                     Name:
                                          --------------------------------------

                                     Signature:
                                               ---------------------------------

                                     Address:
                                             -----------------------------------
                                     -------------------------------------------
                                     -------------------------------------------

                                       Note:    The above signature  should
                                                correspond  exactly with the
                                                name on the face of the Warrant
                                                attached hereto.

and, if said number of shares of Common Stock shall not be all the shares
purchasable under the Warrant attached hereto, a new Warrant is to be issued in
the name of said undersigned covering the balance of the shares purchasable
thereunder less any fraction of a share paid in cash.

<PAGE>

                               FORM OF ASSIGNMENT

         FOR VALUE RECEIVED, the undersigned hereby sells, assigns, and
transfers all the rights of the undersigned under the Warrant attached hereto,
with respect to the number of shares of Common Stock covered thereby set forth
hereinbelow, to:

Name of Assignee                 Address               No of Shares
----------------                 -------               ------------

, and hereby irrevocably constitutes and appoints
____________________________________ as agent and attorney-in-fact to transfer
said Warrant on the books of the within-named corporation, with full power of
substitution in the premises.

Dated:  ________ __, 200_

In the presence of:

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

                                     Name:
                                          -----------------------------------

                                     Signature:
                                          ------------------------------------

                                     Title of Signing Officer or Agent (if any):

                                     Address:
                                             -----------------------------------
                                     -------------------------------------------
                                     -------------------------------------------

                                     Note: The above signature should correspond
                                     exactly with the name on the face of the
                                     Warrant attached hereto.

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