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                                                                    Exhibit 10.1

                               INDEMNITY AGREEMENT

         This Indemnity Agreement, dated as of ____________, 2002, is made by
and between MitoKor, Inc., a Delaware corporation (the "COMPANY") and
____________ (the "INDEMNITEE").

                                    RECITALS

         A.       The Company is aware that competent and experienced persons
are increasingly reluctant to serve as directors, officers or agents of
corporations unless they are protected by comprehensive liability insurance or
indemnification, due to increased exposure to litigation costs and risks
resulting from their service to such corporations, and due to the fact that the
exposure frequently bears no reasonable relationship to the compensation of such
directors, officers and other agents.

         B.       The statutes and judicial decisions regarding the duties of
directors and officers are often difficult to apply, ambiguous, or conflicting,
and therefore fail to provide such directors, officers and agents with adequate,
reliable knowledge of legal risks to which they are exposed or information
regarding the proper course of action to take.

         C.       Plaintiffs often seek damages in such large amounts and the
costs of litigation may be so enormous (whether or not the case is meritorious),
that the defense and/or settlement of such litigation is often beyond the
personal resources of directors, officers and other agents.

         D.       The Company believes that it is unfair for its directors,
officers and agents and the directors, officers and agents of its
subsidiaries to assume the risk of huge judgments and other expenses which
may occur in cases in which the director, officer or agent received no
personal profit and in cases where the director, officer or agent was not
culpable.

         E.       The Company recognizes that the issues in controversy in
litigation against a director, officer or agent of a corporation such as the
Company or its subsidiaries are often related to the knowledge, motives and
intent of such director, officer or agent, that he is usually the only witness
with knowledge of the essential facts and exculpating circumstances regarding
such matters, and that the long period of time which usually elapses before the
trial or other disposition of such litigation often extends beyond the time that
the director, officer or agent can reasonably recall such matters; and may
extend beyond the normal time for retirement for such director, officer or agent
with the result that he, after retirement or in the event of his death, his
spouse, heirs, executors or administrators, may be faced with limited ability
and undue hardship in maintaining an adequate defense, which may discourage such
a director, officer or agent from serving in that position.

         F.       Based upon their experience as business managers, the Board of
Directors of the Company (the "BOARD OF DIRECTORS") has concluded that, to
retain and attract talented and experienced individuals to serve as directors,
officers and agents of the Company and its subsidiaries and to encourage such
individuals to take the business risks necessary for the success of the Company
and its subsidiaries, it is necessary for the Company to contractually indemnify
its directors, officers and agents and the directors, officers and agents of its
subsidiaries, and to assume for itself maximum liability for expenses and
damages in connection

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with claims against such directors, officers and agents in connection with their
service to the Company and its subsidiaries, and has further concluded that the
failure to provide such contractual indemnification could result in great harm
to the Company and its subsidiaries and the Company's stockholders.

         G.       Section 145 of the General Corporation Law of Delaware, under
which the Company is organized ("SECTION 145"), empowers the Company to
indemnify its directors, officers, employees and agents by agreement and to
indemnify persons who serve, at the request of the Company, as the directors,
officers, employees or agents of other corporations or enterprises, and
expressly provides that the indemnification provided by Section 145 is not
exclusive.

         H.       The Company desires and has requested the Indemnitee to serve
or continue to serve as a director, officer or agent of the Company and/or one
or more subsidiaries of the Company free from undue concern for claims for
damages arising out of or related to such services to the Company and/or one or
more subsidiaries of the Company.

         I.       Indemnitee is willing to serve, or to continue to serve, the
Company and/or one or more subsidiaries of the Company, provided that he is
furnished the indemnity provided for herein.

                                    AGREEMENT

         NOW, THEREFORE, the parties hereto, intending to be legally bound,
hereby agree as follows:

         1.       DEFINITIONS.

                  (a)      AGENT. For the purposes of this Agreement, "agent" of
the Company means any person who is or was a director, officer, employee or
other agent of the Company or a subsidiary of the Company; or is or was serving
at the request of, for the convenience of, or to represent the interests of the
Company or a subsidiary of the Company as a director, officer, employee or agent
of another foreign or domestic corporation, partnership, joint venture, trust or
other enterprise; or was a director, officer, employee or agent of a foreign or
domestic corporation which was a predecessor corporation of the Company or a
subsidiary of the Company, or was a director, officer, employee or agent of
another enterprise at the request of, for the convenience of, or to represent
the interests of such predecessor corporation.

                  (b)      EXPENSES. For purposes of this Agreement, "expenses"
include all out-of-pocket costs of any type or nature whatsoever (including,
without limitation, all attorneys' fees and related disbursements), actually and
reasonably incurred by the Indemnitee in connection with either the
investigation, defense or appeal of a proceeding or establishing or enforcing a
right to indemnification under this Agreement or Section 145 or otherwise;
provided, however, that "expenses" shall not include any judgments, fines, ERISA
excise taxes or penalties, or amounts paid in settlement of a proceeding.

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                  (c)      PROCEEDING. For the purposes of this Agreement,
"proceeding" means any threatened, pending, or completed action, suit or other
proceeding, whether civil, criminal, administrative, or investigative.

                  (d)      SUBSIDIARY. For purposes of this Agreement,
"subsidiary" means any corporation of which more than 50% of the outstanding
voting securities is owned directly or indirectly by the Company, by the Company
and one or more other subsidiaries, or by one or more other subsidiaries.

         2.       AGREEMENT TO SERVE. The Indemnitee agrees to serve and/or
continue to serve as agent of the Company, at its will (or under separate
agreement, if such agreement exists), in the capacity Indemnitee currently
serves as an agent of the Company, so long as he is duly appointed or elected
and qualified in accordance with the applicable provisions of the Bylaws of the
Company or any subsidiary of the Company or until such time as he tenders his
resignation in writing; provided, however, that nothing contained in this
Agreement is intended to create any right to continued employment by Indemnitee.

         3.       LIABILITY INSURANCE.

                  (a)      MAINTENANCE OF D&O INSURANCE. The Company hereby
covenants and agrees that, so long as the Indemnitee shall continue to serve as
an agent of the Company and thereafter so long as the Indemnitee shall be
subject to any possible proceeding by reason of the fact that the Indemnitee was
an agent of the Company, the Company, subject to Section 3(c), shall promptly
obtain and maintain in full force and effect directors' and officers' liability
insurance ("D&O Insurance") in reasonable amounts from established and reputable
insurers.

                  (b)      RIGHTS AND BENEFITS. In all policies of D&O
Insurance, the Indemnitee shall be named as an insured in such a manner as to
provide the Indemnitee the same rights and benefits as are accorded to the most
favorably insured of the Company's directors, if the Indemnitee is a director;
or of the Company's officers, if the Indemnitee is not a director of the Company
but is an officer; or of the Company's key employees, if the Indemnitee is not a
director or officer but is a key employee.

                  (c)      LIMITATION ON REQUIRED MAINTENANCE OF D&O INSURANCE.
Notwithstanding the foregoing, the Company shall have no obligation to obtain or
maintain D&O Insurance if the Company determines in good faith that such
insurance is not reasonably available, the premium costs for such insurance are
disproportionate to the amount of coverage provided, the coverage provided by
such insurance is limited by exclusions so as to provide an insufficient
benefit, or the Indemnitee is covered by similar insurance maintained by a
subsidiary of the Company.

         4.       MANDATORY INDEMNIFICATION. Subject to Section 9 below, the
Company shall indemnify the Indemnitee as follows:

                  (a)      SUCCESSFUL DEFENSE. To the extent the Indemnitee has
been successful on the merits or otherwise in defense of any proceeding
(including, without limitation, an action by or in the right of the Company) to
which the Indemnitee was a party by reason of the fact that he is or was an
agent of the Company at any time, against all expenses of any type whatsoever

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actually and reasonably incurred by him in connection with the investigation,
defense or appeal of such proceeding.

                  (b)      THIRD PARTY ACTIONS. If the Indemnitee is a person
who was or is a party or is threatened to be made a party to any proceeding
(other than an action by or in the right of the Company) by reason of the fact
that he is or was an agent of the Company, or by reason of anything done or not
done by him in any such capacity, the Company shall indemnify the Indemnitee
against any and all expenses and liabilities of any type whatsoever (including,
but not limited to, judgments, fines, ERISA excise taxes and penalties, and
amounts paid in settlement) actually and reasonably incurred by him in
connection with the investigation, defense, settlement or appeal of such
proceeding, provided the Indemnitee acted in good faith and in a manner he
reasonably believed to be in or not opposed to the best interests of the Company
and its stockholders, and, with respect to any criminal action or proceeding,
had no reasonable cause to believe his conduct was unlawful.

                  (c)      DERIVATIVE ACTIONS. If the Indemnitee is a person who
was or is a party or is threatened to be made a party to any proceeding by or in
the right of the Company by reason of the fact that he is or was an agent of the
Company, or by reason of anything done or not done by him in any such capacity,
the Company shall indemnify the Indemnitee against all expenses actually and
reasonably incurred by him in connection with the investigation, defense,
settlement, or appeal of such proceeding, provided the Indemnitee acted in good
faith and in a manner he reasonably believed to be in or not opposed to the best
interests of the Company and its stockholders; except that no indemnification
under this subsection 4(c) shall be made in respect to any claim, issue or
matter as to which such person shall have been finally adjudged to be liable to
the Company by a court of competent jurisdiction unless and only to the extent
that the court in which such proceeding was brought shall determine upon
application that, despite the adjudication of liability but in view of all the
circumstances of the case, such person is fairly and reasonably entitled to
indemnity for such amounts which the court shall deem proper.

                  (d)      ACTIONS WHERE INDEMNITEE IS DECEASED. If the
Indemnitee is a person who was or is a party or is threatened to be made a party
to any proceeding by reason of the fact that he is or was an agent of the
Company, or by reason of anything done or not done by him in any such capacity,
and if prior to, during the pendency of after completion of such proceeding
Indemnitee becomes deceased, the Company shall indemnify the Indemnitee's heirs,
executors and administrators against any and all expenses and liabilities of any
type whatsoever (including, but not limited to, judgments, fines, ERISA excise
taxes and penalties, and amounts paid in settlement) actually and reasonably
incurred to the extent Indemnitee would have been entitled to indemnification
pursuant to Sections 4(a), 4(b), or 4(c) above were Indemnitee still alive.

                  (e)      Notwithstanding the foregoing, the Company shall not
be obligated to indemnify the Indemnitee for expenses or liabilities of any type
whatsoever (including, but not limited to, judgments, fines, ERISA excise taxes
and penalties, and amounts paid in settlement) for which payment is actually
made to or on behalf of Indemnitee under a valid and collectible insurance
policy of D&O Insurance, or under a valid and enforceable indemnity clause,
bylaw or agreement.

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         5.       PARTIAL INDEMNIFICATION. If the Indemnitee is entitled under
any provision of this Agreement to indemnification by the Company for some or a
portion of any expenses or liabilities of any type whatsoever (including, but
not limited to, judgments, fines, ERISA excise taxes and penalties, and amounts
paid in settlement) incurred by him in the investigation, defense, settlement or
appeal of a proceeding, but not entitled, however, to indemnification for all of
the total amount hereof, the Company shall nevertheless indemnify the Indemnitee
for such total amount except as to the portion hereof to which the Indemnitee is
not entitled.

         6.       MANDATORY ADVANCEMENT OF EXPENSES. Subject to Section 8(a)
below, the Company shall advance all expenses incurred by the Indemnitee in
connection with the investigation, defense, settlement or appeal of any
proceeding to which the Indemnitee is a party or is threatened to be made a
party by reason of the fact that the Indemnitee is or was an agent of the
Company. Indemnitee hereby undertakes to repay such amounts advanced only if,
and to the extent that, it shall be determined ultimately that the Indemnitee is
not entitled to be indemnified by the Company as authorized hereby. The advances
to be made hereunder shall be paid by the Company to the Indemnitee within
twenty (20) days following delivery of a written request therefor by the
Indemnitee to the Company. In the event that the Company fails to pay expenses
as incurred by the Indemnitee as required by this paragraph, Indemnitee may seek
mandatory injunctive relief from any court having jurisdiction to require the
Company to pay expenses as set forth in this paragraph. If Indemnitee seeks
mandatory injunctive relief pursuant to this paragraph, it shall not be a
defense to enforcement of the Company's obligations set forth in this paragraph
that Indemnitee has an adequate remedy at law for damages.

         7.       NOTICE AND OTHER INDEMNIFICATION PROCEDURES.

                  (a)      Promptly after receipt by the Indemnitee of notice of
the commencement of or the threat of commencement of any proceeding, the
Indemnitee shall, if the Indemnitee believes that indemnification with respect
thereto may be sought from the Company under this Agreement, notify the Company
of the commencement or threat of commencement thereof.

                  (b)      If, at the time of the receipt of a notice of the
commencement of a proceeding pursuant to Section 7(a) hereof, the Company has
D&O Insurance in effect, the Company shall give prompt notice of the
commencement of such proceeding to the insurers in accordance with the
procedures set forth in the respective policies. The Company shall thereafter
take all necessary or desirable action to cause such insurers to pay, on behalf
of the Indemnitee, all amounts payable as a result of such proceeding in
accordance with the terms of such policies.

                  (c)      In the event the Company shall be obligated to pay
the expenses of any proceeding against the Indemnitee, the Company, if
appropriate, shall be entitled to assume the defense of such proceeding, with
counsel approved by the Indemnitee, upon the delivery to the Indemnitee of
written notice of its election so to do. After delivery of such notice, approval
of such counsel by the Indemnitee and the retention of such counsel by the
Company, the Company will not be liable to the Indemnitee under this Agreement
for any fees of counsel subsequently incurred by the Indemnitee with respect to
the same proceeding, provided that (i) the Indemnitee shall have the right to
employ his counsel in any such proceeding at the Indemnitee's expense; and (ii)
if (A) the employment of counsel by the Indemnitee has been previously
authorized by

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the Company, (B) the Indemnitee shall have reasonably concluded that there may
be a conflict of interest between the Company and the Indemnitee in the conduct
of any such defense, or (C) the Company shall not, in fact, have employed
counsel to assume the defense of such proceeding, then the fees and expenses of
Indemnitee's counsel shall be at the expense of the Company.

         8.       EXCEPTIONS. Any other provision herein to the contrary
notwithstanding, the Company shall not be obligated pursuant to the terms of
this Agreement:

                  (a)      CLAIMS INITIATED BY INDEMNITEE. To indemnify or
advance expenses to the Indemnitee with respect to proceedings or claims
initiated or brought voluntarily by the Indemnitee and not by way of defense,
unless (i) such indemnification is expressly required to be made by law, (ii)
the proceeding was authorized by the Board of Directors, (iii) such
indemnification is provided by the Company, in its sole discretion, pursuant to
the powers vested in the Company under the General Corporation Law of Delaware,
or (iv) the proceeding is brought to establish or enforce a right to
indemnification under this Agreement or any other statute or law or otherwise as
required under Section 145;

                  (b)      LACK OF GOOD FAITH. To indemnify the Indemnitee for
any expenses incurred by the Indemnitee with respect to any proceeding
instituted by the Indemnitee to enforce or interpret this Agreement, if a court
of competent jurisdiction determines that each of the material assertions made
by the Indemnitee in such proceeding was not made in good faith or was
frivolous; or

                  (c)      UNAUTHORIZED SETTLEMENTS. To indemnify the Indemnitee
under this Agreement for any amounts paid in settlement of a proceeding unless
the Company consents to such settlement, which consent shall not be unreasonably
withheld.

         9.       NON-EXCLUSIVITY. The provisions for indemnification and
advancement of expenses set forth in this Agreement shall not be deemed
exclusive of any other rights which the Indemnitee may have under any provision
of law, the Company's Certificate of Incorporation or Bylaws, the vote of the
Company's stockholders or disinterested directors, other agreements, or
otherwise, both as to action in his official capacity and to action in another
capacity while occupying his position as an agent of the Company, and the
Indemnitee's rights hereunder shall continue after the Indemnitee has ceased
acting as an agent of the Company and shall inure to the benefit of the heirs,
executors and administrators of the Indemnitee.

         10.      ENFORCEMENT. Any right to indemnification or advances granted
by this Agreement to Indemnitee shall be enforceable by or on behalf of
Indemnitee in any court of competent jurisdiction if (i) the claim for
indemnification or advances is denied, in whole or in part, or (ii) no
disposition of such claim is made within ninety (90) days of request therefor.
Indemnitee, in such enforcement action, if successful in whole or in part, shall
be entitled to be paid also the expense of prosecuting his claim. It shall be a
defense to any action for which a claim for indemnification is made under this
Agreement (other than an action brought to enforce a claim for expenses pursuant
to Section 6 hereof, provided that the required undertaking has been tendered to
the Company) that Indemnitee is not entitled to indemnification because of the
limitations set forth in Sections 4 and 8 hereof. Neither the failure of the
Corporation (including its Board of Directors or its stockholders) to have made
a determination prior to the

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commencement of such enforcement action that indemnification of Indemnitee is
proper in the circumstances, nor an actual determination by the Company
(including its Board of Directors or its stockholders) that such indemnification
is improper, shall be a defense to the action or create a presumption that
Indemnitee is not entitled to indemnification under this Agreement or otherwise.

         11.      SUBROGATION. In the event of payment under this Agreement, the
Company shall be subrogated to the extent of such payment to all of the rights
of recovery of Indemnitee, who shall execute all documents required and shall do
all acts that may be necessary to secure such rights and to enable the Company
effectively to bring suit to enforce such rights.

         12.      SURVIVAL OF RIGHTS.

                  (a)      All agreements and obligations of the Company
contained herein shall continue during the period Indemnitee is an agent of the
Company and shall continue thereafter so long as Indemnitee shall be subject to
any possible claim or threatened, pending or completed action, suit or
proceeding, whether civil, criminal, arbitrational, administrative or
investigative, by reason of the fact that Indemnitee was serving in the capacity
referred to herein.

                  (b)      The Company shall require any successor to the
Company (whether direct or indirect, by purchase, merger, consolidation or
otherwise) to all or substantially all of the business or assets of the Company,
expressly to assume and agree to perform this Agreement in the same manner and
to the same extent that the Company would be required to perform if no such
succession had taken place.

         13.      INTERPRETATION OF AGREEMENT. It is understood that the parties
hereto intend this Agreement to be interpreted and enforced so as to provide
indemnification to the Indemnitee to the fullest extent permitted by law
including those circumstances in which indemnification would otherwise be
discretionary.

         14.      SEVERABILITY. If any provision or provisions of this Agreement
shall be held to be invalid, illegal or unenforceable for any reason whatsoever,
(i) the validity, legality and enforceability of the remaining provisions of the
Agreement (including without limitation, all portions of any paragraphs of this
Agreement containing any such provision held to be invalid, illegal or
unenforceable, that are not themselves invalid, illegal or unenforceable) shall
not in any way be affected or impaired thereby and (ii) to the fullest extent
possible, the provisions of this Agreement (including, without limitation, all
portions of any paragraph of this Agreement containing any such provision held
to be invalid, illegal or unenforceable, that are not themselves invalid,
illegal or unenforceable) shall be construed so as to give effect to the intent
manifested by the provision held invalid, illegal or unenforceable and to give
effect to Section 13 hereof.

         15.      MODIFICATION AND WAIVER. No supplement, modification or
amendment of this Agreement shall be binding unless executed in writing by both
of the parties hereto. No waiver of any of the provisions of this Agreement
shall be deemed or shall constitute a waiver of any other provisions hereof
(whether or not similar) nor shall such waiver constitute a continuing waiver.

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         16.      NOTICE. All notices, requests, demands and other
communications under this Agreement shall be in writing and shall be deemed duly
given (i) if delivered by hand and receipted for by the party addressee or (ii)
if mailed by certified or registered mail with postage prepaid, on the third
business day after the mailing date. Addresses for notice to either party are as
shown on the signature page of this Agreement, or as subsequently modified by
written notice.

         17.      GOVERNING LAW. This Agreement shall be governed exclusively by
and construed according to the laws of the State of Delaware as applied to
contracts between Delaware residents entered into and to be performed entirely
within Delaware.

         The parties hereto have entered into this Indemnity Agreement effective
as of the date first above written.

                                        COMPANY:

                                        MITOKOR, INC.

                                        By:
                                           -------------------------------------

                                        Title:
                                              ----------------------------------

                                        Address:   11494 Sorrento Valley Road
                                                   San Diego, California 92121
                                                   Attn:
                                                        ------------------------

                                        INDEMNITEE:

                                        ----------------------------------------
                                        [NAME]

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

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

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

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                                                                    EXHIBIT 10.2

                                     MITOKOR

                              AMENDED AND RESTATED

                             1993 STOCK OPTION PLAN

     1.   ESTABLISHMENT, PURPOSE AND TERM OF PLAN.

          1.1  ESTABLISHMENT. The Company's 1993 Stock Plan was initially
established effective November 1, 1993 (the "INITIAL PLAN"). The Initial Plan is
hereby amended and restated in its entirety as the MitoKor Amended and Restated
1993 Stock Option Plan (the "PLAN") effective as of October 24, 1996, as amended
(the "EFFECTIVE DATE").

          1.2  PURPOSE. The purpose of the Plan is to advance the interests of
the Participating Company Group and its shareholders by providing an incentive
to attract, retain and reward persons performing services for the Participating
Company Group and by motivating such persons to contribute to the growth and
profitability of the Participating Company Group.

          1.3  TERM OF PLAN. The Plan shall continue in effect until the earlier
of its termination by the Board or the date on which all of the shares of Stock
available for issuance under the Plan have been issued and all restrictions on
such shares under the terms of the Plan and the agreements evidencing Options
granted under the Plan have lapsed. However, all Options shall be granted, if at
all, within ten (10) years from the earlier of the date the Plan is adopted by
the Board or the date the Plan is duly approved by the shareholders of the
Company.

     2.   DEFINITIONS AND CONSTRUCTION.

          2.1  DEFINITIONS. Whenever used herein, the following terms shall have
their respective meanings set forth below:

               (a)  "BOARD" means the Board of Directors of the Company. If one
or more Committees have been appointed by the Board to administer the Plan,
"Board" also means such Committee(s).

               (b)  "CODE" means the Internal Revenue Code of 1986, as amended,
and any applicable regulations promulgated thereunder.

               (c)  "COMMITTEE" means the Compensation Committee or other
committee of the Board duly appointed to administer the Plan and having such
powers as shall be specified by the Board. Unless the powers of the Committee
have been specifically limited, the Committee shall have all of the powers of
the Board granted herein, including, without limitation, the power to amend or
terminate the Plan at any time, subject to the terms of the Plan and any
applicable limitations imposed by law.

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               (d)  "COMPANY" means MitoKor, a California corporation, or any
successor corporation thereto.

               (e)  "CONSULTANT" means any person, including an advisor, engaged
by a Participating Company to render services other than as an Employee or a
Director.

               (f)  "DIRECTOR" means a member of the Board or of the board of
directors of any other Participating Company.

               (g)  "EMPLOYEE" means any person treated as an employee
(including an officer or a Director who is also treated as an employee) in the
records of a Participating Company; provided, however, that neither service as a
Director nor payment of a director's fee shall be sufficient to constitute
employment for purposes of the Plan.

               (h)  "FAIR MARKET VALUE" means, as of any date, the value of a
share of stock or other property as determined by the Board, in its sole
discretion, or by the Company, in its sole discretion, if such determination is
expressly allocated to the Company herein.

               (i)  "INCENTIVE STOCK OPTION" means an Option intended to be (as
set forth in the Option Agreement) and which qualifies as an incentive stock
option within the meaning of Section 422(b) of the Code.

               (j)  "NONSTATUTORY STOCK OPTION" means an Option not intended to
be (as set forth in the Option Agreement) or which does not qualify as an
Incentive Stock Option.

               (k)  "OPTION" means a right to purchase Stock (subject to
adjustment as provided in Section 4.2) pursuant to the terms and conditions of
the Plan. An Option may be either an Incentive Stock Option or a Nonstatutory
Stock Option.

               (l)  "OPTION AGREEMENT" means a written agreement between the
Company and an Optionee setting forth the terms, conditions and restrictions of
the Option granted to the Optionee and any shares acquired upon the exercise
thereof.

               (m)  "OPTIONEE" means a person who has been granted one or more
Options.

               (n)  "PARENT CORPORATION" means any present or future "parent
corporation" of the Company, as defined in Section 424(e) of the Code.

               (o)  "PARTICIPATING COMPANY" means the Company or any Parent
Corporation or Subsidiary Corporation.

               (p)  "PARTICIPATING COMPANY GROUP" means, at any point in time,
all corporations collectively which are then Participating Companies.

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               (q)  "STOCK" means the common stock, without par value, of the
Company, as adjusted from time to time in accordance with Section 4.2.

               (r)  "SUBSIDIARY CORPORATION" means any present or future
"subsidiary corporation" of the Company, as defined in Section 424(f) of the
Code.

               (s)  "TEN PERCENT OWNER OPTIONEE" means an Optionee who, at the
time an Option is granted to the Optionee, owns stock possessing more than ten
percent (10%) of the total combined voting power of all classes of stock of a
Participating Company within the meaning of Section 422(b)(6) of the Code.

          2.2  CONSTRUCTION. Captions and titles contained herein are for
convenience only and shall not affect the meaning or interpretation of any
provision of the Plan. Except when otherwise indicated by the context, the
singular shall include the plural, the plural shall include the singular, and
the term "or" shall include the conjunctive as well as the disjunctive.

     3.   ADMINISTRATION.

          3.1  ADMINISTRATION BY THE BOARD. The Plan shall be administered by
the Board, including any duly appointed Committee of the Board. All questions of
interpretation of the Plan or of any Option shall be determined by the Board,
and such determinations shall be final and binding upon all persons having an
interest in the Plan or such Option. Any officer of a Participating Company
shall have the authority to act on behalf of the Company with respect to any
matter, right, obligation, determination or election which is the responsibility
of or which is allocated to the Company herein, provided the officer has
apparent authority with respect to such matter, right, obligation, determination
or election.

          3.2  POWERS OF THE BOARD. In addition to any other powers set forth in
the Plan and subject to the provisions of the Plan, the Board shall have the
full and final power and authority, in its sole discretion:

               (a)  to determine the persons to whom, and the time or times at
which, Options shall be granted and the number of shares of Stock to be subject
to each Option;

               (b)  to designate Options as Incentive Stock Options or
Nonstatutory Stock Options;

               (c)  to determine the Fair Market Value of shares of Stock or
other property;

               (d)  to determine the terms, conditions and restrictions
applicable to each Option (which need not be identical) and any shares acquired
upon the exercise thereof, including, without limitation, (i) the exercise price
of the Option, (ii) the method of payment for shares purchased upon the exercise
of the Option, (iii) the method for satisfaction of any tax

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withholding obligation arising in connection with the Option or such shares,
including by the withholding or delivery of shares of stock, (iv) the timing,
terms and conditions of the exercisability of the Option or the vesting of any
shares acquired upon the exercise thereof, (v) the time of the expiration of the
Option, (vi) the effect of the Optionee's termination of employment or service
with the Participating Company Group on any of the foregoing, and (vii) all
other terms, conditions and restrictions applicable to the Option or such shares
not inconsistent with the terms of the Plan;

               (e)  to approve one or more forms of Option Agreement;

               (f)  to amend, modify, extend, or renew, or grant a new Option in
substitution for, any Option or to waive any restrictions or conditions
applicable to any Option or any shares acquired upon the exercise thereof;

               (g)  to accelerate, continue, extend or defer the exercisability
of any Option or the vesting of any shares acquired upon the exercise thereof,
including with respect to the period following an Optionee's termination of
employment or service with the Participating Company Group;

               (h)  to prescribe, amend or rescind rules, guidelines and
policies relating to the Plan, or to adopt supplements to, or alternative
versions of, the Plan, including, without limitation, as the Board deems
necessary or desirable to comply with the laws of, or to accommodate the tax
policy or custom of, foreign jurisdictions whose citizens may be granted
Options; and

               (i)  to correct any defect, supply any omission or reconcile any
inconsistency in the Plan or any Option Agreement and to make all other
determinations and take such other actions with respect to the Plan or any
Option as the Board may deem advisable to the extent consistent with the Plan
and applicable law.

     4.   SHARES SUBJECT TO PLAN.

          4.1  MAXIMUM NUMBER OF SHARES ISSUABLE. Subject to adjustment as
provided in Section 4.2, the maximum aggregate number of shares of Stock that
may be issued under the Plan shall be Two Million Four Hundred Sixty Thousand
(2,460,000) and shall consist of authorized but unissued or reacquired shares of
Stock or any combination thereof. If an outstanding Option for any reason
expires or is terminated or canceled or shares of Stock acquired, subject to
repurchase, upon the exercise of an Option are repurchased by the Company, the
shares of Stock allocable to the unexercised portion of such Option, or such
repurchased shares of Stock, shall again be available for issuance under the
Plan.

          4.2  ADJUSTMENTS FOR CHANGES IN CAPITAL STRUCTURE. In the event of any
stock dividend, stock split, reverse stock split, recapitalization, combination,
reclassification or similar change in the capital structure of the Company,
appropriate adjustments shall be made in the number and class of shares subject
to the Plan and to any outstanding Options and in the exercise

                                        4
<Page>

price per share of any outstanding Options. If a majority of the shares which
are of the same class as the shares that are subject to outstanding Options are
exchanged for, converted into, or otherwise become (whether or not pursuant to
an Ownership Change Event, as defined in Section 8.1) shares of another
corporation (the "NEW SHARES"), the Board may unilaterally amend the outstanding
Options to provide that such Options are exercisable for New Shares. In the
event of any such amendment, the number of shares subject to, and the exercise
price per share of, the outstanding Options shall be adjusted in a fair and
equitable manner as determined by the Board, in its sole discretion.
Notwithstanding the foregoing, any fractional share resulting from an adjustment
pursuant to this Section 4.2 shall be rounded up or down to the nearest whole
number, as determined by the Board, and in no event may the exercise price of
any Option be decreased to an amount less than the par value, if any, of the
stock subject to the Option. The adjustments determined by the Board pursuant to
this Section 4.2 shall be final, binding and conclusive.

     5.   ELIGIBILITY AND OPTION LIMITATIONS.

          5.1  PERSONS ELIGIBLE FOR OPTIONS. Options may be granted only to
Employees, Consultants, and Directors. For purposes of the foregoing sentence,
"Employees" shall include prospective Employees to whom Options are granted in
connection with written offers of employment with the Participating Company
Group, and "Consultants" shall include prospective Consultants to whom Options
are granted in connection with written offers of engagement with the
Participating Company Group. Eligible persons may be granted more than one (1)
Option.

          5.2  OPTION GRANT RESTRICTIONS. Any person who is not an Employee on
the effective date of the grant of an Option to such person may be granted only
a Nonstatutory Stock Option. An Incentive Stock Option granted to a prospective
Employee upon the condition that such person become an Employee shall be deemed
granted effective on the date such person commences service with a Participating
Company, with an exercise price determined as of such date in accordance with
Section 6.1.

          5.3  FAIR MARKET VALUE LIMITATION. To the extent that the aggregate
Fair Market Value of stock with respect to which options designated as Incentive
Stock Options are exercisable by an Optionee for the first time during any
calendar year (under all stock option plans of the Participating Company Group,
including the Plan) exceeds One Hundred Thousand Dollars ($100,000), the portion
of such options which exceeds such amount shall be treated as Nonstatutory Stock
Options. For purposes of this Section 5.3, options designated as Incentive Stock
Options shall be taken into account in the order in which they were granted, and
the Fair Market Value of stock shall be determined as of the time the option
with respect to such stock is granted. If the Code is amended to provide for a
different limitation from that set forth in this Section 5.3, such different
limitation shall be deemed incorporated herein effective as of the date and with
respect to such Options as required or permitted by such amendment to the Code.
If an Option is treated as an Incentive Stock Option in part and as a
Nonstatutory Stock Option in part by reason of the limitation set forth in this
Section 5.3, the Optionee may designate which portion of such Option the
Optionee is exercising and may request that separate certificates representing
each such portion be issued upon the exercise of the Option. In the absence of
such designation,

                                        5
<Page>

the Optionee shall be deemed to have exercised the Incentive Stock Option
portion of the Option first.

     6.   TERMS AND CONDITIONS OF OPTIONS. Options shall be evidenced by Option
Agreements specifying the number of shares of Stock covered thereby, in such
form as the Board shall from time to time establish. Option Agreements may
incorporate all or any of the terms of the Plan by reference and shall comply
with and be subject to the following terms and conditions:

          6.1  EXERCISE PRICE. The exercise price for each Option shall be
established in the sole discretion of the Board; provided, however, that (a) the
exercise price per share for an Incentive Stock Option shall be not less than
the Fair Market Value of a share of Stock on the effective date of grant of the
Option, (b) the exercise price per share for a Nonstatutory Stock Option shall
be not less than eighty-five percent (85%) of the Fair Market Value of a share
of Stock on the effective date of grant of the Option, and (c) no Option granted
to a Ten Percent Owner Optionee shall have an exercise price per share less than
one hundred ten percent (110%) of the Fair Market Value of a share of Stock on
the effective date of grant of the Option. Notwithstanding the foregoing, an
Option (whether an Incentive Stock Option or a Nonstatutory Stock Option) may be
granted with an exercise price lower than the minimum exercise price set forth
above if such Option is granted pursuant to an assumption or substitution for
another option in a manner qualifying under the provisions of Section 424(a) of
the Code.

          6.2  EXERCISE PERIOD. Options shall be exercisable at such time or
times, or upon such event or events, and subject to such terms, conditions,
performance criteria, and restrictions as shall be determined by the Board and
set forth in the Option Agreement evidencing such Option; provided, however,
that (a) no Option shall be exercisable after the expiration of ten (10) years
after the effective date of grant of such Option, (b) no Incentive Stock Option
granted to a Ten Percent Owner Optionee shall be exercisable after the
expiration of five (5) years after the effective date of grant of such Option,
and (c) no Option granted to a prospective Employee or prospective Consultant
may become exercisable prior to the date on which such person commences service
with a Participating Company.

          6.3  PAYMENT OF EXERCISE PRICE.

               (a) FORMS OF CONSIDERATION AUTHORIZED. Except as otherwise
provided below, payment of the exercise price for the number of shares of Stock
being purchased pursuant to any Option shall be made (i) in cash, by check, or
cash equivalent, (ii) by tender to the Company of shares of Stock owned by the
Optionee having a Fair Market Value (as determined by the Company without regard
to any restrictions on transferability applicable to such stock by reason of
federal or state securities laws or agreements with an underwriter for the
Company) not less than the exercise price, (iii) by the assignment of the
proceeds of a sale or loan with respect to some or all of the shares being
acquired upon the exercise of the Option (including, without limitation, through
an exercise complying with the provisions of Regulation T as promulgated from
time to time by the Board of Governors of the Federal Reserve System) (a
"CASHLESS EXERCISE"), (iv) by the Optionee's promissory note in a form approved
by the Company, (v) by such other consideration as may be approved by the Board

                                        6
<Page>

from time to time to the extent permitted by applicable law, or (vi) by any
combination thereof. The Board may at any time or from time to time, by adoption
of or by amendment to the standard forms of Option Agreement described in
Section 7, or by other means, grant Options which do not permit all of the
foregoing forms of consideration to be used in payment of the exercise price or
which otherwise restrict one or more forms of consideration.

               (b)  TENDER OF STOCK. Notwithstanding the foregoing, an Option
may not be exercised by tender to the Company of shares of Stock to the extent
such tender of Stock would constitute a violation of the provisions of any law,
regulation or agreement restricting the redemption of the Company's stock.
Unless otherwise provided by the Board, an Option may not be exercised by tender
to the Company of shares of Stock unless such shares either have been owned by
the Optionee for more than six (6) months or were not acquired, directly or
indirectly, from the Company.

               (c)  CASHLESS EXERCISE. The Company reserves, at any and all
times, the right, in the Company's sole and absolute discretion, to establish,
decline to approve or terminate any program or procedures for the exercise of
Options by means of a Cashless Exercise.

               (d)  PAYMENT BY PROMISSORY NOTE. No promissory note shall be
permitted if the exercise of an Option using a promissory note would be a
violation of any law. Any permitted promissory note shall be on such terms as
the Board shall determine at the time the Option is granted. The Board shall
have the authority to permit or require the Optionee to secure any promissory
note used to exercise an Option with the shares of Stock acquired upon the
exercise of the Option or with other collateral acceptable to the Company.
Unless otherwise provided by the Board, if the Company at any time is subject to
the regulations promulgated by the Board of Governors of the Federal Reserve
System or any other governmental entity affecting the extension of credit in
connection with the Company's securities, any promissory note shall comply with
such applicable regulations, and the Optionee shall pay the unpaid principal and
accrued interest, if any, to the extent necessary to comply with such applicable
regulations.

          6.4  TAX WITHHOLDING. The Company shall have the right, but not the
obligation, to deduct from the shares of Stock issuable upon the exercise of an
Option, or to accept from the Optionee the tender of, a number of whole shares
of Stock having a Fair Market Value, as determined by the Company, equal to all
or any part of the federal, state, local and foreign taxes, if any, required by
law to be withheld by the Participating Company Group with respect to such
Option or the shares acquired upon the exercise thereof. Alternatively or in
addition, in its sole discretion, the Company shall have the right to require
the Optionee, through payroll withholding, cash payment or otherwise, including
by means of a Cashless Exercise, to make adequate provision for any such tax
withholding obligations of the Participating Company Group arising in connection
with the Option or the shares acquired upon the exercise thereof. The Company
shall have no obligation to deliver shares of Stock or to release shares of
Stock from an escrow established pursuant to the Option Agreement until the
Participating Company Group's tax withholding obligations have been satisfied by
the Optionee.

                                        7
<Page>

          6.5  REPURCHASE RIGHTS. Shares issued under the Plan may be subject to
a right of first refusal, one or more repurchase options, or other conditions
and restrictions as determined by the Board in its sole discretion at the time
the Option is granted. The Company shall have the right to assign at any time
any repurchase right it may have, whether or not such right is then exercisable,
to one or more persons as may be selected by the Company. Upon request by the
Company, each Optionee shall execute any agreement evidencing such transfer
restrictions prior to the receipt of shares of Stock hereunder and shall
promptly present to the Company any and all certificates representing shares of
Stock acquired hereunder for the placement on such certificates of appropriate
legends evidencing any such transfer restrictions.

     7.   STANDARD FORMS OF OPTION AGREEMENT.

          7.1  INCENTIVE STOCK OPTIONS. Unless otherwise provided by the Board
at the time the Option is granted, an Option designated as an "Incentive Stock
Option" shall comply with and be subject to the terms and conditions set forth
in the form of Incentive Stock Option Agreement adopted by the Board
concurrently with its adoption of the Plan and as amended from time to time.

          7.2  NONSTATUTORY STOCK OPTIONS. Unless otherwise provided by the
Board at the time the Option is granted, an Option designated as a "Nonstatutory
Stock Option" shall comply with and be subject to the terms and conditions set
forth in the form of Nonstatutory Stock Option Agreement adopted by the Board
concurrently with its adoption of the Plan and as amended from time to time.

          7.3  STANDARD TERM OF OPTIONS. Except as otherwise provided in Section
6.2 or by the Board in the grant of an Option, any Option granted hereunder
shall have a term of ten (10) years from the effective date of grant of the
Option.

          7.4  AUTHORITY TO VARY TERMS. The Board shall have the authority from
time to time to vary the terms of any of the standard forms of Option Agreement
described in this Section 7 either in connection with the grant or amendment of
an individual Option or in connection with the authorization of a new standard
form or forms; provided, however, that the terms and conditions of any such new,
revised or amended standard form or forms of Option Agreement shall be in
accordance with the terms of the Plan. Such authority shall include, but not by
way of limitation, the authority to grant Options which are immediately
exercisable subject to the Company's right to repurchase any unvested shares of
Stock acquired by an Optionee upon the exercise of an Option in the event such
Optionee's employment or service with the Participating Company Group is
terminated for any reason, with or without cause.

                                        8
<Page>

     8.   TRANSFER OF CONTROL.

          8.1  DEFINITIONS.

               (a)  An "OWNERSHIP CHANGE EVENT" shall be deemed to have occurred
if any of the following occurs with respect to the Company:

                    (i)   the direct or indirect sale or exchange in a single or
series of related transactions by the shareholders of the Company of more than
fifty percent (50%) of the voting stock of the Company;

                    (ii)  a merger or consolidation in which the Company is a
party;

                    (iii) the sale, exchange, or transfer of all or
substantially all of the assets of the Company; or

                    (iv)  a liquidation or dissolution of the Company.

               (b)  A "TRANSFER OF CONTROL" shall mean an Ownership Change Event
or a series of related Ownership Change Events (collectively, the "TRANSACTION")
wherein the shareholders of the Company immediately before the Transaction do
not retain immediately after the Transaction, in substantially the same
proportions as their ownership of shares of the Company's voting stock
immediately before the Transaction, direct or indirect beneficial ownership of
more than fifty percent (50%) of the total combined voting power of the
outstanding voting stock of the Company or the corporation or corporations to
which the assets of the Company were transferred (the "TRANSFEREE
CORPORATION(S)"), as the case may be. For purposes of the preceding sentence,
indirect beneficial ownership shall include, without limitation, an interest
resulting from ownership of the voting stock of one or more corporations which,
as a result of the Transaction, own the Company or the Transferee
Corporation(s), as the case may be, either directly or through one or more
subsidiary corporations. The Board shall have the right to determine whether
multiple sales or exchanges of the voting stock of the Company or multiple
Ownership Change Events are related, and its determination shall be final,
binding and conclusive.

          8.2  EFFECT OF TRANSFER OF CONTROL ON OPTIONS. In the event of a
Transfer of Control, the surviving, continuing, successor, or purchasing
corporation or parent corporation thereof, as the case may be (the "ACQUIRING
CORPORATION"), may either assume the Company's rights and obligations under
outstanding Options or substitute for outstanding Options substantially
equivalent options for the Acquiring Corporation's stock. Any Options which are
neither assumed or substituted for by the Acquiring Corporation in connection
with the Transfer of Control nor exercised as of the date of the Transfer of
Control shall terminate and cease to be outstanding effective as of the date of
the Transfer of Control. Notwithstanding the foregoing, shares acquired upon
exercise of an Option prior to the Transfer of Control and any consideration
received pursuant to the Transfer of Control with respect to such shares shall
continue to be

                                        9
<Page>

subject to all applicable provisions of the Option Agreement evidencing such
Option except as otherwise provided in such Option Agreement. Furthermore,
notwithstanding the foregoing, if the corporation the stock of which is subject
to the outstanding Options immediately prior to an Ownership Change Event
described in Section 8.1(a)(i) constituting a Transfer of Control is the
surviving or continuing corporation and immediately after such Ownership Change
Event less than fifty percent (50%) of the total combined voting power of its
voting stock is held by another corporation or by other corporations that are
members of an affiliated group within the meaning of Section 1504(a) of the Code
without regard to the provisions of Section 1504(b) of the Code, the outstanding
Options shall not terminate unless the Board otherwise provides in its sole
discretion.

     9.   PROVISION OF INFORMATION. At least annually, copies of the Company's
balance sheet and income statement for the just completed fiscal year shall be
made available to each Optionee and purchaser of shares of Stock upon the
exercise of an Option. The Company shall not be required to provide such
information to persons whose duties in connection with the Company assure them
access to equivalent information.

     10.  NONTRANSFERABILITY OF OPTIONS. During the lifetime of the Optionee, an
Option shall be exercisable only by the Optionee or the Optionee's guardian or
legal representative. No Option shall be assignable or transferable by the
Optionee, except by will or by the laws of descent and distribution.

     11.  TRANSFER OF COMPANY'S RIGHTS. In the event any Participating Company
assigns, other than by operation of law, to a third person, other than another
Participating Company, any of the Participating Company's rights to repurchase
any shares of Stock acquired upon the exercise of an Option, the assignee shall
pay to the assigning Participating Company the value of such right as determined
by the Company in the Company's sole discretion. Such consideration shall be
paid in cash. In the event such repurchase right is exercisable at the time of
such assignment, the value of such right shall be not less than the Fair Market
Value of the shares of Stock which may be repurchased under such right (as
determined by the Company) minus the repurchase price of such shares. The
requirements of this Section 11 regarding the minimum consideration to be
received by the assigning Participating Company shall not inure to the benefit
of the Optionee whose shares of Stock are being repurchased. Failure of a
Participating Company to comply with the provisions of this Section 11 shall not
constitute a defense or otherwise prevent the exercise of the repurchase right
by the assignee of such right.

     12.  INDEMNIFICATION. In addition to such other rights of indemnification
as they may have as members of the Board or officers or employees of the
Participating Company Group, members of the Board and any officers or employees
of the Participating Company Group to whom authority to act for the Board is
delegated shall be indemnified by the Company against all reasonable expenses,
including attorneys' fees, actually and necessarily incurred in connection with
the defense of any action, suit or proceeding, or in connection with any appeal
therein, to which they or any of them may be a party by reason of any action
taken or failure to act under or in connection with the Plan, or any right
granted hereunder, and against all amounts paid by them in settlement thereof
(provided such settlement is approved by independent legal counsel selected

                                       10
<Page>

by the Company) or paid by them in satisfaction of a judgment in any such
action, suit or proceeding, except in relation to matters as to which it shall
be adjudged in such action, suit or proceeding that such person is liable for
gross negligence, bad faith or intentional misconduct in duties; provided,
however, that within sixty (60) days after the institution of such action, suit
or proceeding, such person shall offer to the Company, in writing, the
opportunity at its own expense to handle and defend the same.

     13.  TERMINATION OR AMENDMENT OF PLAN. The Board may terminate or amend the
Plan at any time. However, subject to changes in the law or other legal
requirements that would permit otherwise, without the approval of the Company's
shareholders, there shall be (a) no increase in the maximum aggregate number of
shares of Stock that may be issued under the Plan (except by operation of the
provisions of Section 4.2), (b) no change in the class of persons eligible to
receive Incentive Stock Options, and (c) no expansion in the class of persons
eligible to receive Nonstatutory Stock Options. In any event, no termination or
amendment of the Plan may adversely affect any then outstanding Option or any
unexercised portion thereof, without the consent of the Optionee, unless such
termination or amendment is required to enable an Option designated as an
Incentive Stock Option to qualify as an Incentive Stock Option or is necessary
to comply with any applicable law or government regulation.

     14.  SHAREHOLDER APPROVAL. The Plan or any increase in the maximum number
of shares of Stock issuable thereunder as provided in Section 4.1 (the "MAXIMUM
SHARES") shall be approved by the shareholders of the Company within twelve (12)
months of the date of adoption thereof by the Board. Options granted prior to
shareholder approval of the Plan or in excess of the Maximum Shares previously
approved by the shareholders shall become exercisable no earlier than the date
of shareholder approval of the Plan or such increase in the Maximum Shares, as
the case may be.

     15.  CONTINUATION OF INITIAL PLAN AS TO OUTSTANDING OPTIONS. Any other
provision of the Plan to the contrary notwithstanding, the terms of the Initial
Plan shall remain in effect and apply to all Options and shares of Stock granted
pursuant to the Initial Plan.

                                       11
<Page>

                                  PLAN HISTORY

November 1, 1993          Board adopts Initial Plan, with a share reserve of
                          925,000 shares.

August 15, 1994           Shareholders approve Initial Plan, with a share
                          reserve of 925,000 shares.

April 25, 1996            Board approves a share reserve increase of 8,775,000
                          for a total reserve of 9,700,000 shares.

May 20, 1996              Shareholders approve a share reserve increase of
                          8,775,000 for a total reserve of 9,700,000 shares.

August 26, 1996           Board approves a share reserve increase of 5,000,000
                          for a total reserve of 14,700,000 shares.

October 24, 1996          Shareholders approve a share reserve increase of
                          5,000,000 for a total reserve of 14,700,000 shares.

October 24, 1996          Board amends and restates the Initial Plan as the
                          Plan, with a share reserve of 14,700,000 shares.

October 24, 1996          Shareholders approve amendment and restatement of the
                          Initial Plan as the Plan, with a share reserve of
                          14,700,000 shares.

December 11, 1996         Board approves a share reserve increase of 4,000,000
                          for a total reserve of 18,700,000 shares.

December 11, 1996         Shareholders approve a share reserve increase of
                          4,000,000 for a total reserve of 18,700,000 shares.

March 26, 1997            Board approves a share reserve increase of 300,000 for
                          a total reserve of 19,000,000 shares.

March 26, 1997            Shareholders approve a share reserve increase of
                          300,000 for a total reserve of 19,000,000 shares.

June 30, 1997             Company effects 25:1 reverse stock split, resulting in
                          a total reserve of 760,000 shares.

June 30, 1997             Board approves a share reserve increase of 320,000 for
                          a total reserve of 1,080,000 shares.

<Page>

June 30, 1997             Shareholders approve a share reserve increase of
                          320,000 for a total reserve of 1,080,000 shares.

April 2, 1998             Board approves a share reserve increase of 230,000 for
                          a total reserve of 1,310,000 shares.

April 2, 1998             Shareholders approve a share reserve increase of
                          230,000 for a total reserve of 1,310,000 shares.

December 4, 1998          Board approves a share reserve increase of 250,000 for
                          a total reserve of 1,560,000 shares.

December 4, 1998          Shareholders approve a share reserve increase of
                          250,000 for a total reserve of 1,560,000 shares.

April 19, 2000            Board approves a share reserve increase of 500,000
                          shares for a total reserve of 2,060,000 shares.

April 19, 2000            Shareholders approve a share reserve increase of
                          500,000 for a total reserve of 2,060,00 shares.

May 3, 2001               Board approves a share reserve increase of 400,000
                          shares for a total reserve of 2,460,000 shares.

<Page>

THE SECURITIES WHICH ARE THE SUBJECT OF THIS AGREEMENT HAVE NOT BEEN QUALIFIED
WITH THE COMMISSIONER OF CORPORATIONS OF THE STATE OF CALIFORNIA AND THE
ISSUANCE OF SUCH SECURITIES OR THE PAYMENT OR RECEIPT OF ANY PART OF THE
CONSIDERATION THEREFOR PRIOR TO SUCH QUALIFICATION IS UNLAWFUL, UNLESS THE SALE
OF SECURITIES IS EXEMPT FROM QUALIFICATION BY SECTION 25100, 25102, OR 25105 OF
THE CALIFORNIA CORPORATIONS CODE. THE RIGHTS OF ALL PARTIES TO THIS AGREEMENT
ARE EXPRESSLY CONDITIONED UPON SUCH QUALIFICATION BEING OBTAINED, UNLESS THE
SALE IS SO EXEMPT.

THE SECURITY REPRESENTED BY THIS CERTIFICATE HAS BEEN ACQUIRED FOR INVESTMENT
AND NOT WITH A VIEW TO, OR IN CONNECTION WITH, THE SALE OR DISTRIBUTION THEREOF.
NO SUCH SALE OR DISPOSITION MAY BE EFFECTED WITHOUT AN EFFECTIVE REGISTRATION
STATEMENT RELATED THERETO OR AN OPINION OF COUNSEL SATISFACTORY TO THE COMPANY
THAT SUCH REGISTRATION IS NOT REQUIRED UNDER THE SECURITIES ACT OF 1933.

                                     MITOKOR

                        INCENTIVE STOCK OPTION AGREEMENT

     THIS INCENTIVE STOCK OPTION AGREEMENT (the "OPTION AGREEMENT") is made and
entered into as of ________, 19___ by and between MitoKor and _________________
(the "OPTIONEE").

     The Company has granted to the Optionee pursuant to the MitoKor Amended and
Restated 1993 Stock Option Plan (the "PLAN") an option to purchase certain
shares of Stock, upon the terms and conditions set forth in this Option
Agreement (the "OPTION"). The Option shall in all respects be subject to the
terms and conditions of the Plan, the provisions of which are incorporated
herein by reference.

     1.   DEFINITIONS AND CONSTRUCTION.

          1.1.  DEFINITIONS. Unless otherwise defined herein, capitalized terms
shall have the meanings assigned to such terms in the Plan. Whenever used
herein, the following terms shall have their respective meanings set forth
below:

                (a) "DATE OF OPTION GRANT" means __________, 199__.

                (b) "NUMBER OF OPTION SHARES" means _____________________ shares
of Stock, as adjusted from time to time pursuant to Section 9.

                                        1
<Page>

                (c) "EXCHANGE ACT" means the Securities Exchange Act of 1934, as
amended.

                (d) "EXERCISE PRICE" means $ 0.01 per share of Stock, as
adjusted from time to time pursuant to Section 9.

                (e) "INITIAL EXERCISE DATE" means the Initial Vesting Date.

                (f) "INITIAL VESTING DATE" means the date occurring one (1) year
after (check one):

                    -     the Date of Option Grant.

                    -     _____________, 19__, the date the Optionee's Service
                          commenced.

                (g) "VESTED RATIO" means, on any relevant date, the ratio
determined as follows:

<Table>
<Caption>
                                                                 Vested Ratio
                                                                 ------------
               <S>                                               <C>
               Prior to Initial Vesting Date                           0

               On Initial Vesting Date, provided the                 1/5
               Optionee's Service is continuous
               from the Date of Option Grant until
               the Initial Vesting Date

               PLUS

               For each three months of the                         1/20
               Optionee's continuous Service from
               the Initial Vesting Date until the
               Vested Ratio equals 1/1, an
               additional
</Table>

                (h) "OPTION EXPIRATION DATE" means the date ten (10) years after
the Date of Option Grant.

                (i) "COMPANY" means MitoKor, a California corporation, or any
successor corporation thereto.

                (j) "DISABILITY" means the inability of the Optionee, in the
opinion of a qualified physician acceptable to the Company, to perform the major

                (k) "SECURITIES ACT" means the Securities Act of 1933, as
amended.

                                        2
<Page>

                (l) "SERVICE" means the Optionee's employment or service with
the Participating Company Group, whether in the capacity of an Employee, a
Director or a Consultant. The Optionee's Service shall not be deemed to have
terminated merely because of a change in the capacity in which the Optionee
renders Service to the Participating Company Group or a change in the
Participating Company for which the Optionee renders such Service, provided that
there is no interruption or termination of the Optionee's Service. The
Optionee's Service shall be deemed to have terminated either upon an actual
termination of Service or upon the corporation for which the Optionee performs
Service ceasing to be a Participating Company. Subject to the foregoing, the
Company, in its sole discretion, shall determine whether the Optionee's Service
has terminated and the effective date of such termination. (NOTE: If the Option
is exercised more than three (3) months after the date on which the Optionee
ceased to be an Employee (other than by reason of death or a permanent and total
disability as defined in Section 22(e)(3) of the Code), the Option will be
treated as a Nonstatutory Stock Option and not as an Incentive Stock Option to
the extent required by Section 422 of the Code.)

          1.2.  CONSTRUCTION. Captions and titles contained herein are for
convenience only and shall not affect the meaning or interpretation of any
provision of this Option Agreement. Except when otherwise indicated by the
context, the singular shall include the plural, the plural shall include the
singular, and the term "or" shall include the conjunctive as well as the
disjunctive.

     2.   TAX CONSEQUENCES.

          2.1.  TAX STATUS OF OPTION. This Option is intended to be an Incentive
Stock Option within the meaning of Section 422(b) of the Code, but the Company
does not represent or warrant that this Option qualifies as such. The Optionee
should consult with the Optionee's own tax advisor regarding the tax effects of
this Option and the requirements necessary to obtain favorable income tax
treatment under Section 422 of the Code, including, but not limited to, holding
period requirements. (NOTE: If the aggregate Exercise Price of the Option (that
is, the Exercise Price multiplied by the Number of Option Shares) plus the
aggregate exercise price of any other Incentive Stock Options held by the
Optionee (whether granted pursuant to the Plan or any other stock option plan of
the Participating Company Group) is greater than One Hundred Thousand Dollars
($100,000), the Optionee should contact the Chief Financial Officer of the
Company to ascertain whether the entire Option qualifies as an Incentive Stock
Option.)

          2.2.  ELECTION UNDER SECTION 83(b) OF THE CODE. If the Optionee
exercises this Option to purchase shares of Stock that are both nontransferable
and subject to a substantial risk of forfeiture, the Optionee understands that
the Optionee should consult with the Optionee's tax advisor regarding the
advisability of filing with the Internal Revenue Service an election under
Section 83(b) of the Code, which must be filed no later than thirty (30) days
after the date on which the Optionee exercises the Option. Shares acquired upon
exercise of the Option are nontransferable and subject to a substantial risk of
forfeiture if, for example, (a) they are unvested and are subject to a right of
the Company to repurchase such shares at the Optionee's original purchase price
if the Optionee's Service terminates, or (b) the Optionee is subject to a
restriction on transfer to comply with "Pooling-of-Interests Accounting" rules.
Failure to file an

                                        3
<Page>

election under Section 83(b), if appropriate, may result in adverse tax
consequences to the Optionee. The Optionee acknowledges that the Optionee has
been advised to consult with a tax advisor prior to the exercise of the Option
regarding the tax consequences to the Optionee of the exercise of the Option. AN
ELECTION UNDER SECTION 83(b) MUST BE FILED WITHIN 30 DAYS AFTER THE DATE ON
WHICH THE OPTIONEE PURCHASES SHARES. THIS TIME PERIOD CANNOT BE EXTENDED. THE
OPTIONEE ACKNOWLEDGES THAT TIMELY FILING OF A SECTION 83(b) ELECTION IS THE
OPTIONEE'S SOLE RESPONSIBILITY, EVEN IF THE OPTIONEE REQUESTS THE COMPANY OR ITS
REPRESENTATIVE TO FILE SUCH ELECTION ON HIS OR HER BEHALF.

     3.   ADMINISTRATION. All questions of interpretation concerning this Option
Agreement shall be determined by the Board, including any duly appointed
Committee of the Board. All determinations by the Board shall be final and
binding upon all persons having an interest in the Option. Any officer of a
Participating Company shall have the authority to act on behalf of the Company
with respect to any matter, right, obligation, or election which is the
responsibility of or which is allocated to the Company herein, provided the
officer has apparent authority with respect to such matter, right, obligation,
or election.

     4.   EXERCISE OF THE OPTION.

          4.1.  RIGHT TO EXERCISE. Except as otherwise provided herein, the
Option shall be exercisable on and after the Initial Exercise Date and prior to
the termination of the Option (as provided in Section 6) in an amount not to
exceed the Number of Option Shares multiplied by the Vested Ratio, less the
number of shares previously acquired upon exercise of the Option, subject to the
Optionee's agreement that any shares purchased upon exercise are subject to the
Company's repurchase rights set forth in Section 11. In no event shall the
Option be exercisable for more shares than the Number of Option Shares.

          4.2.  METHOD OF EXERCISE. Exercise of the Option shall be by written
notice to the Company which must state the election to exercise the Option, the
number of whole shares of Stock for which the Option is being exercised and such
other representations and agreements as to the Optionee's investment intent with
respect to such shares as may be required pursuant to the provisions of this
Option Agreement. The written notice must be signed by the Optionee and must be
delivered in person, by certified or registered mail, return receipt requested,
by confirmed facsimile transmission, or by such other means as the Company may
permit, to the Chief Financial Officer of the Company, or other authorized
representative of the Participating Company Group, prior to the termination of
the Option as set forth in Section 6, accompanied by (i) full payment of the
aggregate Exercise Price for the number of shares of Stock being purchased and
(ii) an executed copy, if required herein, of the then current forms of escrow
and security agreement referenced below. The Option shall be deemed to be
exercised upon receipt by the Company of such written notice, the aggregate
Exercise Price, and, if required by the Company, such executed agreements.

                                        4
<Page>

          4.3.  PAYMENT OF EXERCISE PRICE.

                (a) FORMS OF CONSIDERATION AUTHORIZED. Except as otherwise
provided below, payment of the aggregate Exercise Price for the number of shares
of Stock for which the Option is being exercised shall be made (i) in cash, by
check, or cash equivalent, (ii) by tender to the Company of whole shares of
Stock owned by the Optionee having a Fair Market Value (as determined by the
Company without regard to any restrictions on transferability applicable to such
stock by reason of federal or state securities laws or agreements with an
underwriter for the Company) not less than the aggregate Exercise Price, (iii)
by means of a Cashless Exercise, as defined in Section 4.3(c), (iv) in the
Company's sole discretion at the time the Option is exercised, by the Optionee's
promissory note for the aggregate Exercise Price, or (v) by any combination of
the foregoing.

                (b) TENDER OF STOCK. Notwithstanding the foregoing, the Option
may not be exercised by tender to the Company of shares of Stock to the extent
such tender of Stock would constitute a violation of the provisions of any law,
regulation or agreement restricting the redemption of the Company's stock. The
Option may not be exercised by tender to the Company of shares of Stock unless
such shares either have been owned by the Optionee for more than six (6) months
or were not acquired, directly or indirectly, from the Company.

                (c) CASHLESS EXERCISE. A "CASHLESS EXERCISE" means the
assignment in a form acceptable to the Company of the proceeds of a sale or loan
with respect to some or all of the shares of Stock acquired upon the exercise of
the Option pursuant to a program or procedure approved by the Company
(including, without limitation, through an exercise complying with the
provisions of Regulation T as promulgated from time to time by the Board of
Governors of the Federal Reserve System). The Company reserves, at any and all
times, the right, in the Company's sole and absolute discretion, to decline to
approve or terminate any such program or procedure.

                (d) PAYMENT BY PROMISSORY NOTE. No promissory note shall be
permitted if an exercise of the Option using a promissory note would be a
violation of any law. The promissory note permitted in clause (iv) of Section
4.3(a) shall be a full recourse note in a form satisfactory to the Company, with
principal payable no more than four (4) years after the date the Option is
exercised. Interest on the principal balance of the promissory note shall be
payable in annual installments at the minimum interest rate necessary to avoid
imputed interest pursuant to all applicable sections of the Code. Such recourse
promissory note shall be secured by the shares of Stock acquired pursuant to the
then current form of security agreement as approved by the Company. At any time
the Company is subject to the regulations promulgated by the Board of Governors
of the Federal Reserve System or any other governmental entity affecting the
extension of credit in connection with the Company's securities, any promissory
note shall comply with such applicable regulations, and the Optionee shall pay
the unpaid principal and accrued interest, if any, to the extent necessary to
comply with such applicable regulations. Except as the Company in its sole
discretion shall determine, the Optionee shall pay the unpaid principal balance
of the promissory note and any accrued interest thereon upon termination of the
Optionee's Service with the Participating Company Group for any reason, with or
without cause.

                                        5
<Page>

          4.4.  TAX WITHHOLDING. At the time the Option is exercised, in whole
or in part, or at any time thereafter as requested by the Company, the Optionee
hereby authorizes withholding from payroll and any other amounts payable to the
Optionee, and otherwise agrees to make adequate provision for (including by
means of a Cashless Exercise to the extent permitted by the Company), any sums
required to satisfy the federal, state, local and foreign tax withholding
obligations of the Participating Company Group, if any, which arise in
connection with the Option, including, without limitation, obligations arising
upon (i) the exercise, in whole or in part, of the Option, (ii) the transfer, in
whole or in part, of any shares acquired upon exercise of the Option, (iii) the
operation of any law or regulation providing for the imputation of interest, or
(iv) the lapsing of any restriction with respect to any shares acquired upon
exercise of the Option. The Optionee is cautioned that the Option is not
exercisable unless the tax withholding obligations of the Participating Company
Group are satisfied. Accordingly, the Optionee may not be able to exercise the
Option when desired even though the Option is vested, and the Company shall have
no obligation to issue a certificate for such shares or release such shares from
any escrow provided for herein.

          4.5.  CERTIFICATE REGISTRATION. Except in the event the Exercise Price
is paid by means of a Cashless Exercise, the certificate for the shares as to
which the Option is exercised shall be registered in the name of the Optionee,
or, if applicable, in the names of the heirs of the Optionee.

          4.6.  RESTRICTIONS ON GRANT OF THE OPTION AND ISSUANCE OF SHARES. The
grant of the Option and the issuance of shares of Stock upon exercise of the
Option shall be subject to compliance with all applicable requirements of
federal, state or foreign law with respect to such securities. The Option may
not be exercised if the issuance of shares of Stock upon exercise would
constitute a violation of any applicable federal, state or foreign securities
laws or other law or regulations or the requirements of any stock exchange or
market system upon which the Stock may then be listed. In addition, the Option
may not be exercised unless (i) a registration statement under the Securities
Act shall at the time of exercise of the Option be in effect with respect to the
shares issuable upon exercise of the Option or (ii) in the opinion of legal
counsel to the Company, the shares issuable upon exercise of the Option may be
issued in accordance with the terms of an applicable exemption from the
registration requirements of the Securities Act. THE OPTIONEE IS CAUTIONED THAT
THE OPTION MAY NOT BE EXERCISED UNLESS THE FOREGOING CONDITIONS ARE SATISFIED.
ACCORDINGLY, THE OPTIONEE MAY NOT BE ABLE TO EXERCISE THE OPTION WHEN DESIRED
EVEN THOUGH THE OPTION IS VESTED. The inability of the Company to obtain from
any regulatory body having jurisdiction the authority, if any, deemed by the
Company's legal counsel to be necessary to the lawful issuance and sale of any
shares subject to the Option shall relieve the Company of any liability in
respect of the failure to issue or sell such shares as to which such requisite
authority shall not have been obtained. As a condition to the exercise of the
Option, the Company may require the Optionee to satisfy any qualifications that
may be necessary or appropriate, to evidence compliance with any applicable law
or regulation and to make any representation or warranty with respect thereto as
may be requested by the Company.

                                        6
<Page>

          4.7.  FRACTIONAL SHARES. The Company shall not be required to issue
fractional shares upon the exercise of the Option.

     5.   NONTRANSFERABILITY OF THE OPTION. The Option may be exercised during
the lifetime of the Optionee only by the Optionee or the Optionee's guardian or
legal representative and may not be assigned or transferred in any manner except
by will or by the laws of descent and distribution. Following the death of the
Optionee, the Option, to the extent provided in Section 7, may be exercised by
the Optionee's legal representative or by any person empowered to do so under
the deceased Optionee's will or under the then applicable laws of descent and
distribution.

     6.   TERMINATION OF THE OPTION. The Option shall terminate and may no
longer be exercised on the first to occur of (a) the Option Expiration Date, (b)
the last date for exercising the Option following termination of the Optionee's
Service as described in Section 7, or (c) a Transfer of Control to the extent
provided in Section 8.

     7.   EFFECT OF TERMINATION OF SERVICE.

          7.1.  OPTION EXERCISABILITY.

                (a) DISABILITY. If the Optionee's Service with the Participating
Company Group is terminated because of the Disability of the Optionee, the
Option, to the extent unexercised and exercisable on the date on which the
Optionee's Service terminated, may be exercised by the Optionee (or the
Optionee's guardian or legal representative) at any time prior to the expiration
of six (6) months after the date on which the Optionee's Service terminated, but
in any event no later than the Option Expiration Date. (NOTE: If the Option is
exercised more than three (3) months after the date on which the Optionee's
Service as an Employee terminated as a result of a Disability other than a
permanent and total disability as defined in Section 22(e)(3) of the Code, the
Option will be treated as a Nonstatutory Stock Option and not as an Incentive
Stock Option to the extent required by Section 422 of the Code.)

                (b) DEATH. If the Optionee's Service with the Participating
Company Group is terminated because of the death of the Optionee, the Option, to
the extent unexercised and exercisable on the date on which the Optionee's
Service terminated, may be exercised by the Optionee (or the Optionee's legal
representative, or other person who acquired the right to exercise the Option by
reason of the Optionee's death) at any time prior to the expiration of six (6)
months after the date on which the Optionee's Service terminated, but in any
event no later than the Option Expiration Date. The Optionee's Service shall be
deemed to have terminated on account of death if the Optionee dies within ninety
(90) days after the Optionee's termination of Service.

                (c) OTHER TERMINATION OF SERVICE. If the Optionee's Service with
the Participating Company Group terminates for any reason, except Disability or
death, the Option, to the extent unexercised and exercisable by the Optionee on
the date on which the Optionee's Service terminated, may be exercised by the
Optionee within ninety (90) days (or such other longer period of time as
determined by the Board, in its sole discretion) after the date on which the
Optionee's Service terminated, but in any event no later than the Option
Expiration Date.

                                        7
<Page>

          7.2.  ADDITIONAL LIMITATION ON OPTION EXERCISE. Except as the Company
and the Optionee otherwise agree, exercise of the Option pursuant to Section 7.1
following termination of the Optionee's Service may not be made by delivery of a
promissory note as provided in Section 4.3(a).

          7.3.  EXTENSION IF EXERCISE PREVENTED BY LAW. Notwithstanding the
foregoing, if the exercise of the Option within the applicable time periods set
forth in Section 7.1 is prevented by the provisions of Section 4.6, the Option
shall remain exercisable until three (3) months after the date the Optionee is
notified by the Company that the Option is exercisable, but in any event no
later than the Option Expiration Date. The Company makes no representation as to
the tax consequences of any such delayed exercise. The Optionee should consult
with the Optionee's own tax advisor as to the tax consequences of any such
delayed exercise.

          7.4.  EXTENSION IF OPTIONEE SUBJECT TO SECTION 16(b). Notwithstanding
the foregoing, if a sale within the applicable time periods set forth in Section
7.1 of shares acquired upon the exercise of the Option would subject the
Optionee to suit under Section 16(b) of the Exchange Act, the Option shall
remain exercisable until the earliest to occur of (i) the tenth (10th) day
following the date on which a sale of such shares by the Optionee would no
longer be subject to such suit, (ii) the one hundred and ninetieth (190th) day
after the Optionee's termination of Service, or (iii) the Option Expiration
Date. The Company makes no representation as to the tax consequences of any such
delayed exercise. The Optionee should consult with the Optionee's own tax
advisor as to the tax consequences of any such delayed exercise.

          7.5.  LEAVE OF ABSENCE. For purposes of Section 7.1, the Optionee's
Service with the Participating Company Group shall not be deemed to terminate if
the Optionee takes any military leave, sick leave, or other bona fide leave of
absence approved by the Company of ninety (90) days or less. In the event of a
leave of absence in excess of ninety (90) days, the Optionee's Service shall be
deemed to terminate on the ninety-first (91st) day of such leave unless the
Optionee's right to reemployment with the Participating Company Group remains
guaranteed by statute or contract. Notwithstanding the foregoing, unless
otherwise designated by the Company (or required by law), a leave of absence
shall not be treated as Service for purposes of determining the Optionee's
Vested Ratio.

     8.   TRANSFER OF CONTROL.

          8.1.  DEFINITIONS.

                (a) An "OWNERSHIP CHANGE EVENT" shall be deemed to have occurred
if any of the following occurs with respect to the Company:

                    (i)   the direct or indirect sale or exchange in a single or
series of related transactions by the shareholders of the Company of more than
fifty percent (50%) of the voting stock of the Company;

                                        8
<Page>

                    (ii)  a merger or consolidation in which the Company is a
party; or

                    (iii) the sale, exchange, or transfer of all or
substantially all of the assets of the Company; or

                    (iv) a liquidation or dissolution of the Company.

                (b) A "TRANSFER OF CONTROL" shall mean an Ownership Change Event
or a series of related Ownership Change Events (collectively, the "TRANSACTION")
wherein the shareholders of the Company immediately before the Transaction do
not retain immediately after the Transaction, in substantially the same
proportions as their ownership of shares of the Company's voting stock
immediately before the Transaction, direct or indirect beneficial ownership of
more than fifty percent (50%) of the total combined voting power of the
outstanding voting stock of the Company or the corporation or corporations to
which the assets of the Company were transferred (the "TRANSFEREE
CORPORATION(S)"), as the case may be. For purposes of the preceding sentence,
indirect beneficial ownership shall include, without limitation, an interest
resulting from ownership of the voting stock of one or more corporations which,
as a result of the Transaction, own the Company or the Transferee
Corporation(s), as the case may be, either directly or through one or more
subsidiary corporations. The Board shall have the right to determine whether
multiple sales or exchanges of the voting stock of the Company or multiple
Ownership Change Events are related, and its determination shall be final,
binding and conclusive.

          8.2.  EFFECT OF TRANSFER OF CONTROL ON OPTION. In the event of a
Transfer of Control, the surviving, continuing, successor, or purchasing
corporation or parent corporation thereof, as the case may be (the "ACQUIRING
CORPORATION"), may either assume the Company's rights and obligations under the
Option or substitute for the Option a substantially equivalent option for the
Acquiring Corporation's stock. The Option shall terminate and cease to be
outstanding effective as of the date of the Transfer of Control to the extent
that the Option is neither assumed or substituted for by the Acquiring
Corporation in connection with the Transfer of Control nor exercised as of the
date of the Transfer of Control. Notwithstanding the foregoing, shares acquired
upon exercise of the Option prior to the Transfer of Control and any
consideration received pursuant to the Transfer of Control with respect to such
shares shall continue to be subject to all applicable provisions of this Option
Agreement except as otherwise provided herein. Furthermore, notwithstanding the
foregoing, if the corporation the stock of which is subject to the Option
immediately prior to an Ownership Change Event described in Section 8.1(a)(i)
constituting a Transfer of Control is the surviving or continuing corporation
and immediately after such Ownership Change Event less than fifty percent (50%)
of the total combined voting power of its voting stock is held by another
corporation or by other corporations that are members of an affiliated group
within the meaning of Section 1504(a) of the Code without regard to the
provisions of Section 1504(b) of the Code, the Option shall not terminate unless
the Board otherwise provides in its sole discretion.

     9.   ADJUSTMENTS FOR CHANGES IN CAPITAL STRUCTURE. In the event of any
stock dividend, stock split, reverse stock split, recapitalization, combination,
reclassification, or similar

                                        9
<Page>

change in the capital structure of the Company, appropriate adjustments shall be
made in the number, Exercise Price and class of shares of stock subject to the
Option. If a majority of the shares which are of the same class as the shares
that are subject to the Option are exchanged for, converted into, or otherwise
become (whether or not pursuant to an Ownership Change Event) shares of another
corporation (the "NEW SHARES"), the Board may unilaterally amend the Option to
provide that the Option is exercisable for New Shares. In the event of any such
amendment, the Number of Option Shares and the Exercise Price shall be adjusted
in a fair and equitable manner, as determined by the Board, in its sole
discretion. Notwithstanding the foregoing, any fractional share resulting from
an adjustment pursuant to this Section 9 shall be rounded up or down to the
nearest whole number, as determined by the Board, and in no event may the
Exercise Price be decreased to an amount less than the par value, if any, of the
stock subject to the Option. The adjustments determined by the Board pursuant to
this Section 9 shall be final, binding and conclusive.

     10.  RIGHTS AS A SHAREHOLDER, EMPLOYEE OR CONSULTANT. The Optionee shall
have no rights as a shareholder with respect to any shares covered by the Option
until the date of the issuance of a certificate for the shares for which the
Option has been exercised (as evidenced by the appropriate entry on the books of
the Company or of a duly authorized transfer agent of the Company). No
adjustment shall be made for dividends, distributions or other rights for which
the record date is prior to the date such certificate is issued, except as
provided in Section 9. Nothing in this Option Agreement shall confer upon the
Optionee any right to continue in the Service of a Participating Company or
interfere in any way with any right of the Participating Company Group to
terminate the Optionee's Service as an Employee or Consultant, as the case may
be, at any time.

     11.  RIGHT OF FIRST REFUSAL.

          11.1. GRANT OF RIGHT OF FIRST REFUSAL. Except as provided in Section
11.7 below, in the event the Optionee, the Optionee's legal representative, or
other holder of shares acquired upon exercise of the Option proposes to sell,
exchange, transfer, pledge, or otherwise dispose of any shares acquired upon
exercise of the Option (the "TRANSFER SHARES") to any person or entity,
including, without limitation, any shareholder of the Participating Company
Group, the Company shall have the right to repurchase the Transfer Shares under
the terms and subject to the conditions set forth in this Section 11 (the "RIGHT
OF FIRST REFUSAL").

          11.2. NOTICE OF PROPOSED TRANSFER. Prior to any proposed transfer of
the Transfer Shares, the Optionee shall give a written notice (the "TRANSFER
NOTICE") to the Company describing fully the proposed transfer, including the
number of Transfer Shares, the name and address of the proposed transferee (the
"PROPOSED TRANSFEREE") and, if the transfer is voluntary, the proposed transfer
price, and containing such information necessary to show the bona fide nature of
the proposed transfer. In the event of a bona fide gift or involuntary transfer,
the proposed transfer price shall be deemed to be the Fair Market Value of the
Transfer Shares, as determined by the Board in good faith. If the Optionee
proposes to transfer any Transfer Shares to more than one Proposed Transferee,
the Optionee shall provide a separate Transfer Notice for the proposed transfer
to each Proposed Transferee. The Transfer Notice shall be signed by both the
Optionee and the Proposed Transferee and must constitute a binding

                                       10
<Page>

commitment of the Optionee and the Proposed Transferee for the transfer of the
Transfer Shares to the Proposed Transferee subject only to the Right of First
Refusal.

          11.3. BONA FIDE TRANSFER. If the Company determines that the
information provided by the Optionee in the Transfer Notice is insufficient to
establish the bona fide nature of a proposed voluntary transfer, the Company
shall give the Optionee written notice of the Optionee's failure to comply with
the procedure described in this Section 11, and the Optionee shall have no right
to transfer the Transfer Shares without first complying with the procedure
described in this Section 11. The Optionee shall not be permitted to transfer
the Transfer Shares if the proposed transfer is not bona fide.

          11.4. EXERCISE OF RIGHT OF FIRST REFUSAL. If the Company determines
the proposed transfer to be bona fide, the Company shall have the right to
purchase all, but not less than all, of the Transfer Shares (except as the
Company and the Optionee otherwise agree) at the purchase price and on the terms
set forth in the Transfer Notice by delivery to the Optionee of a notice of
exercise of the Right of First Refusal within thirty (30) days after the date
the Transfer Notice is delivered to the Company. The Company's exercise or
failure to exercise the Right of First Refusal with respect to any proposed
transfer described in a Transfer Notice shall not affect the Company's right to
exercise the Right of First Refusal with respect to any proposed transfer
described in any other Transfer Notice, whether or not such other Transfer
Notice is issued by the Optionee or issued by a person other than the Optionee
with respect to a proposed transfer to the same Proposed Transferee. If the
Company exercises the Right of First Refusal, the Company and the Optionee shall
thereupon consummate the sale of the Transfer Shares to the Company on the terms
set forth in the Transfer Notice within sixty (60) days after the date the
Transfer Notice is delivered to the Company (unless a longer period is offered
by the Proposed Transferee); provided, however, that in the event the Transfer
Notice provides for the payment for the Transfer Shares other than in cash, the
Company shall have the option of paying for the Transfer Shares by the present
value cash equivalent of the consideration described in the Transfer Notice as
reasonably determined by the Company. For purposes of the foregoing,
cancellation of any indebtedness of the Optionee to any Participating Company
shall be treated as payment to the Optionee in cash to the extent of the unpaid
principal and any accrued interest canceled.

          11.5. FAILURE TO EXERCISE RIGHT OF FIRST REFUSAL. If the Company fails
to exercise the Right of First Refusal in full (or to such lesser extent as the
Company and the Optionee otherwise agree) within the period specified in Section
11.4 above, the Optionee may conclude a transfer to the Proposed Transferee of
the Transfer Shares on the terms and conditions described in the Transfer
Notice, provided such transfer occurs not later than ninety (90) days following
delivery to the Company of the Transfer Notice. The Company shall have the right
to demand further assurances from the Optionee and the Proposed Transferee (in a
form satisfactory to the Company) that the transfer of the Transfer Shares was
actually carried out on the terms and conditions described in the Transfer
Notice. No Transfer Shares shall be transferred on the books of the Company
until the Company has received such assurances, if so demanded, and has approved
the proposed transfer as bona fide. Any proposed transfer on terms and
conditions different from those described in the Transfer Notice, as well as any
subsequent

                                       11
<Page>

proposed transfer by the Optionee, shall again be subject to the Right of First
Refusal and shall require compliance by the Optionee with the procedure
described in this Section 11.

          11.6. TRANSFEREES OF TRANSFER SHARES. All transferees of the Transfer
Shares or any interest therein, other than the Company, shall be required as a
condition of such transfer to agree in writing (in a form satisfactory to the
Company) that such transferee shall receive and hold such Transfer Shares or
interest therein subject to all of the terms and conditions of this Option
Agreement, including this Section 11 providing for the Right of First Refusal
with respect to any subsequent transfer. Any sale or transfer of any shares
acquired upon exercise of the Option shall be void unless the provisions of this
Section 11 are met.

          11.7. TRANSFERS NOT SUBJECT TO RIGHT OF FIRST REFUSAL. The Right of
First Refusal shall not apply to any transfer or exchange of the shares acquired
upon exercise of the Option if such transfer or exchange is in connection with
an Ownership Change Event. If the consideration received pursuant to such
transfer or exchange consists of stock of a Participating Company, such
consideration shall remain subject to the Right of First Refusal unless the
provisions of Section 11.9 below result in a termination of the Right of First
Refusal.

          11.8. ASSIGNMENT OF RIGHT OF FIRST REFUSAL. The Company shall have the
right to assign the Right of First Refusal at any time, whether or not there has
been an attempted transfer, to one or more persons as may be selected by the
Company.

          11.9. EARLY TERMINATION OF RIGHT OF FIRST REFUSAL. The other
provisions of this Option Agreement notwithstanding, the Right of First Refusal
shall terminate and be of no further force and effect upon (a) the occurrence of
a Transfer of Control, unless the Acquiring Corporation assumes the Company's
rights and obligations under the Option or substitutes a substantially
equivalent option for the Acquiring Corporation's stock for the Option, or (b)
the existence of a public market for the class of shares subject to the Right of
First Refusal. A "PUBLIC MARKET" shall be deemed to exist if (i) such stock is
listed on a national securities exchange (as that term is used in the Exchange
Act) or (ii) such stock is traded on the over-the-counter market and prices
therefor are published daily on business days in a recognized financial journal.

     12.  ESCROW.

          12.1. ESTABLISHMENT OF ESCROW. To ensure that shares subject to the
Right of First Refusal or securing any promissory note will be available for
repurchase, the Company may require the Optionee to deposit the certificate
evidencing the shares which the Optionee purchases upon exercise of the Option
with an agent designated by the Company under the terms and conditions of escrow
and security agreements approved by the Company. If the Company does not require
such deposit as a condition of exercise of the Option, the Company reserves the
right at any time to require the Optionee to so deposit the certificate in
escrow. Upon the occurrence of an Ownership Change Event or a change, as
described in Section 9, in the character or amount of any of the outstanding
stock of the corporation the stock of which is subject to the provisions of this
Option Agreement, any and all new, substituted or additional securities or other
property to which the Optionee is entitled by reason of the Optionee's

                                       12
<Page>

ownership of shares of Stock acquired upon exercise of the Option that remain,
following such Ownership Change Event or change described in Section 9, subject
to the Right of First Refusal or any security interest held by the Company shall
be immediately subject to the escrow to the same extent as such shares of Stock
immediately before such event. The Company shall bear the expenses of the
escrow.

          12.2. DELIVERY OF SHARES TO OPTIONEE. As soon as practicable after the
expiration of the Right of First Refusal and after full repayment of any
promissory note secured by the shares or other property in escrow, but not more
frequently than twice each calendar year, the escrow agent shall deliver to the
Optionee the shares and any other property no longer subject to such restriction
and no longer securing any promissory note.

          12.3. NOTICES AND PAYMENTS. In the event the shares and any other
property held in escrow are subject to the Company's exercise of the Right of
First Refusal, the notices required to be given to the Optionee shall be given
to the escrow agent, and any payment required to be given to the Optionee shall
be given to the escrow agent. Within thirty (30) days after payment by the
Company, the escrow agent shall deliver the shares and any other property which
the Company has purchased to the Company and shall deliver the payment received
from the Company to the Optionee.

     13.  STOCK DISTRIBUTIONS SUBJECT TO OPTION AGREEMENT. If, from time to
time, there is any stock dividend, stock split or other change, as described in
Section 9, in the character or amount of any of the outstanding stock of the
corporation the stock of which is subject to the provisions of this Option
Agreement, then in such event any and all new, substituted or additional
securities to which the Optionee is entitled by reason of the Optionee's
ownership of the shares acquired upon exercise of the Option shall be
immediately subject to the Right of First Refusal and any security interest held
by the Company with the same force and effect as the shares subject to the Right
of First Refusal and such security interest immediately before such event.

                                       13
<Page>

     14.  NOTICE OF SALES UPON DISQUALIFYING DISPOSITION. The Optionee shall
dispose of the shares acquired pursuant to the Option only in accordance with
the provisions of this Option Agreement. In addition, the Optionee shall
promptly notify the Chief Financial Officer of the Company if the Optionee
disposes of any of the shares acquired pursuant to the Option within one (1)
year after the date of the Optionee exercises all or part of the Option or
within two (2) years after the Date of Option Grant. Until such time as the
Optionee disposes of such shares in a manner consistent with the provisions of
this Option Agreement, unless otherwise expressly authorized by the Company, the
Optionee shall hold all shares acquired pursuant to the Option in the Optionee's
name (and not in the name of any nominee) for the one-year period immediately
after the exercise of the Option and the two-year period immediately after Date
of Option Grant. At any time during the one-year or two-year periods set forth
above, the Company may place a legend on any certificate representing shares
acquired pursuant to the Option requesting the transfer agent for the Company's
stock to notify the Company of any such transfers. The obligation of the
Optionee to notify the Company of any such transfer shall continue
notwithstanding that a legend has been placed on the certificate pursuant to the
preceding sentence.

     15.  LEGENDS. The Company may at any time place legends referencing the
Right of First Refusal, and any applicable federal, state or foreign securities
law restrictions on all certificates representing shares of stock subject to the
provisions of this Option Agreement. The Optionee shall, at the request of the
Company, promptly present to the Company any and all certificates representing
shares acquired pursuant to the Option in the possession of the Optionee in
order to carry out the provisions of this Section. Unless otherwise specified by
the Company, legends placed on such certificates may include, but shall not be
limited to, the following:

          15.1. "THE SECURITIES EVIDENCED BY THIS CERTIFICATE HAVE NOT BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE SOLD,
TRANSFERRED, ASSIGNED OR HYPOTHECATED UNLESS THERE IS AN EFFECTIVE REGISTRATION
STATEMENT UNDER SUCH ACT COVERING SUCH SECURITIES, THE SALE IS MADE IN
ACCORDANCE WITH RULE 144 OR RULE 701 UNDER THE ACT, OR THE COMPANY RECEIVES AN
OPINION OF COUNSEL FOR THE HOLDER OF THESE SECURITIES REASONABLY SATISFACTORY TO
THE COMPANY, STATING THAT SUCH SALE, TRANSFER, ASSIGNMENT OR HYPOTHECATION IS
EXEMPT FROM THE REGISTRATION AND PROSPECTUS DELIVERY REQUIREMENTS OF SUCH ACT."

          15.2. Any legend required to be placed thereon by the Commissioner of
Corporations of the State of California.

          15.3. "THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO A
RIGHT OF FIRST REFUSAL OPTION IN FAVOR OF THE CORPORATION OR ITS ASSIGNEE SET
FORTH IN AN AGREEMENT BETWEEN THE CORPORATION AND THE REGISTERED HOLDER, OR SUCH
HOLDER'S PREDECESSOR IN INTEREST, A COPY OF WHICH IS ON FILE AT THE PRINCIPAL
OFFICE OF THIS CORPORATION."

                                       14
<Page>

          15.4. "THE SHARES EVIDENCED BY THIS CERTIFICATE WERE ISSUED BY THE
CORPORATION TO THE REGISTERED HOLDER UPON EXERCISE OF AN INCENTIVE STOCK OPTION
AS DEFINED IN SECTION 422 OF THE INTERNAL REVENUE CODE OF 1986, AS AMENDED
("ISO"). IN ORDER TO OBTAIN THE PREFERENTIAL TAX TREATMENT AFFORDED TO ISOs, THE
SHARES SHOULD NOT BE TRANSFERRED PRIOR TO ___________. SHOULD THE REGISTERED
HOLDER ELECT TO TRANSFER ANY OF THE SHARES PRIOR TO THIS DATE AND FOREGO ISO TAX
TREATMENT, THE TRANSFER AGENT FOR THE SHARES SHALL NOTIFY THE CORPORATION
IMMEDIATELY. THE REGISTERED HOLDER SHALL HOLD ALL SHARES PURCHASED UNDER THE
INCENTIVE STOCK OPTION IN THE REGISTERED HOLDER'S NAME (AND NOT IN THE NAME OF
ANY NOMINEE) PRIOR TO THIS DATE OR UNTIL TRANSFERRED AS DESCRIBED ABOVE."

     16.  PUBLIC OFFERING. The Optionee hereby agrees that in the event of any
underwritten public offering of stock, including an initial public offering of
stock, made by the Company pursuant to an effective registration statement filed
under the Securities Act, the Optionee shall not offer, sell, contract to sell,
pledge, hypothecate, grant any option to purchase or make any short sale of, or
otherwise dispose of any shares of stock of the Company or any rights to acquire
stock of the Company for such period of time from and after the effective date
of such registration statement as may be established by the underwriter for such
public offering; provided, however, that such period of time shall not exceed
one hundred eighty (180) days from the effective date of the registration
statement to be filed in connection with such public offering. The foregoing
limitation shall not apply to shares registered in the public offering under the
Securities Act. The Optionee shall be subject to this Section provided and only
if the officers and directors of the Company are also subject to similar
arrangements.

     17.  BINDING EFFECT. Subject to the restrictions on transfer set forth
herein, this Option Agreement shall inure to the benefit of and be binding upon
the parties hereto and their respective heirs, executors, administrators,
successors and assigns.

     18.  TERMINATION OR AMENDMENT. The Board may terminate or amend the Plan or
the Option at any time; provided, however, that except as provided in Section
8.2 in connection with a Transfer of Control, no such termination or amendment
may adversely affect the Option or any unexercised portion hereof without the
consent of the Optionee unless such termination or amendment is necessary to
comply with any applicable law or government regulation or is required to enable
the Option to qualify as an Incentive Stock Option. No amendment or addition to
this Option Agreement shall be effective unless in writing.

     19.  INTEGRATED AGREEMENT. This Option Agreement and the Plan constitute
the entire understanding and agreement of the Optionee and the Participating
Company Group with respect to the subject matter contained herein and therein
and there are no agreements, understandings, restrictions, representations, or
warranties among the Optionee and the Participating Company Group with respect
to such subject matter other than those as set forth or provided for herein or
therein. To the extent contemplated herein or therein, the provisions of this
Option Agreement shall survive any exercise of the Option and shall remain in
full force and effect.

                                       15
<Page>

     20.  APPLICABLE LAW. This Option Agreement shall be governed by the laws of
the State of California as such laws are applied to agreements between
California residents entered into and to be performed entirely within the State
of California.

                                               MITOKOR

                                               By:
                                                  -----------------------------

                                               Title:
                                                     ---------------------------

     The Optionee represents that the Optionee is familiar with the terms and
provisions of this Option Agreement, including the Right of First Refusal set
forth in Section 11, and hereby accepts the Option subject to all of the terms
and provisions thereof. The Optionee hereby agrees to accept as binding,
conclusive and final all decisions or interpretations of the Board upon any
questions arising under this Option Agreement. The undersigned acknowledges
receipt of a copy of the Plan.

                                               OPTIONEE

Date:
     ------------------------------------      --------------------------

                                       16
<Page>

THE SECURITIES WHICH ARE THE SUBJECT OF THIS AGREEMENT HAVE NOT BEEN QUALIFIED
WITH THE COMMISSIONER OF CORPORATIONS OF THE STATE OF CALIFORNIA AND THE
ISSUANCE OF SUCH SECURITIES OR THE PAYMENT OR RECEIPT OF ANY PART OF THE
CONSIDERATION THEREFOR PRIOR TO SUCH QUALIFICATION IS UNLAWFUL, UNLESS THE SALE
OF SECURITIES IS EXEMPT FROM QUALIFICATION BY SECTION 25100, 25102, OR 25105 OF
THE CALIFORNIA CORPORATIONS CODE. THE RIGHTS OF ALL PARTIES TO THIS AGREEMENT
ARE EXPRESSLY CONDITIONED UPON SUCH QUALIFICATION BEING OBTAINED, UNLESS THE
SALE IS SO EXEMPT.

THE SECURITY REPRESENTED BY THIS CERTIFICATE HAS BEEN ACQUIRED FOR INVESTMENT
AND NOT WITH A VIEW TO, OR IN CONNECTION WITH, THE SALE OR DISTRIBUTION THEREOF.
NO SUCH SALE OR DISPOSITION MAY BE EFFECTED WITHOUT AN EFFECTIVE REGISTRATION
STATEMENT RELATED THERETO OR AN OPINION OF COUNSEL SATISFACTORY TO THE COMPANY
THAT SUCH REGISTRATION IS NOT REQUIRED UNDER THE SECURITIES ACT OF 1933.

                                     MITOKOR

                       NONSTATUTORY STOCK OPTION AGREEMENT

     THIS NONSTATUTORY STOCK OPTION AGREEMENT (the "OPTION AGREEMENT") is made
and entered into as of _________, 199__, by and between MitoKor and ___________
(the "OPTIONEE").

     The Company has granted to the Optionee pursuant to the MitoKor Amended and
Restated 1993 Stock Option Plan (the "PLAN") an option to purchase certain
shares of Stock, upon the terms and conditions set forth in this Option
Agreement (the "OPTION"). The Option shall in all respects be subject to the
terms and conditions of the Plan, the provisions of which are incorporated
herein by reference.

     1.   DEFINITIONS AND CONSTRUCTION.

          1.1.  DEFINITIONS. Unless otherwise defined herein, capitalized terms
shall have the meanings assigned to such terms in the Plan. Whenever used
herein, the following terms shall have their respective meanings set forth
below:

                (a) "DATE OF OPTION GRANT" means ____________, 199__.

                (b) "NUMBER OF OPTION SHARES" means ____________ shares of
Stock, as adjusted from time to time pursuant to Section 9.

                (c) "EXCHANGE ACT" means the Securities Exchange Act of 1934, as
amended.

                                        1
<Page>

                (d) "EXERCISE PRICE" means $__________ per share of Stock, as
adjusted from time to time pursuant to Section 9.

                (e) "INITIAL EXERCISE DATE" means the Initial Vesting Date.

                (f) DETERMINATION OF VESTING: shares shall be fully vested as of
the Date of Option Grant.

                (g) "OPTION EXPIRATION DATE" means the date ten (10) years after
the Date of Option Grant.

                (h) "COMPANY" means MitoKor, a California corporation, or any
successor corporation thereto.

                (i) "DISABILITY" means the inability of the Optionee, in the
opinion of a qualified physician acceptable to the Company, to perform the major
duties of the Optionee's position with the Participating Company Group because
of the sickness or injury of the Optionee.

                (j) "SECURITIES ACT" means the Securities Act of 1933, as
amended.

                (k) "SERVICE" means the Optionee's employment or service with
the Participating Company Group, whether in the capacity of an Employee, a
Director or a Consultant. The Optionee's Service shall not be deemed to have
terminated merely because of a change in the capacity in which the Optionee
renders Service to the Participating Company Group or a change in the
Participating Company for which the Optionee renders such Service, provided that
there is no interruption or termination of the Optionee's Service. The
Optionee's Service shall be deemed to have terminated either upon an actual
termination of Service or upon the corporation for which the Optionee performs
Service ceasing to be a Participating Company. Subject to the foregoing, the
Company, in its sole discretion, shall determine whether the Optionee's Service
has terminated and the effective date of such termination.

          1.2.  CONSTRUCTION. Captions and titles contained herein are for
convenience only and shall not affect the meaning or interpretation of any
provision of this Option Agreement. Except when otherwise indicated by the
context, the singular shall include the plural, the plural shall include the
singular, and the term "or" shall include the conjunctive as well as the
disjunctive.

     2.   TAX CONSEQUENCES.

          2.1.  TAX STATUS OF OPTION. This Option is intended to be a
Nonstatutory Stock Option and shall not be treated as an Incentive Stock Option
within the meaning of Section 422(b) of the Code.

          2.2.  ELECTION UNDER SECTION 83(b) OF THE CODE. If the Optionee
exercises this Option to purchase shares of Stock that are both nontransferable
and subject to a substantial risk of forfeiture, the Optionee understands that
the Optionee should consult with the Optionee's tax advisor regarding the
advisability of filing with the Internal Revenue Service an election under
Section 83(b) of the Code, which must be filed no later than thirty (30) days
after the date on

                                        2
<Page>

which the Optionee exercises the Option. Shares acquired upon exercise of the
Option are nontransferable and subject to a substantial risk of forfeiture if,
for example, (a) they are unvested and are subject to a right of the Company to
repurchase such shares at the Optionee's original purchase price if the
Optionee's Service terminates, or (b) the Optionee is subject to a restriction
on transfer to comply with "Pooling-of-Interests Accounting" rules. Failure to
file an election under Section 83(b), if appropriate, may result in adverse tax
consequences to the Optionee. The Optionee acknowledges that the Optionee has
been advised to consult with a tax advisor prior to the exercise of the Option
regarding the tax consequences to the Optionee of the exercise of the Option. AN
ELECTION UNDER SECTION 83(b) MUST BE FILED WITHIN 30 DAYS AFTER THE DATE ON
WHICH THE OPTIONEE PURCHASES SHARES. THIS TIME PERIOD CANNOT BE EXTENDED. THE
OPTIONEE ACKNOWLEDGES THAT TIMELY FILING OF A SECTION 83(b) ELECTION IS THE
OPTIONEE'S SOLE RESPONSIBILITY, EVEN IF THE OPTIONEE REQUESTS THE COMPANY OR ITS
REPRESENTATIVE TO FILE SUCH ELECTION ON HIS OR HER BEHALF.

     3.   ADMINISTRATION. All questions of interpretation concerning this Option
Agreement shall be determined by the Board, including any duly appointed
Committee of the Board. All determinations by the Board shall be final and
binding upon all persons having an interest in the Option. Any officer of a
Participating Company shall have the authority to act on behalf of the Company
with respect to any matter, right, obligation, or election which is the
responsibility of or which is allocated to the Company herein, provided the
officer has apparent authority with respect to such matter, right, obligation,
or election.

     4.   EXERCISE OF THE OPTION.

          4.1.  RIGHT TO EXERCISE. Except as otherwise provided herein, the
Option shall be exercisable on and after the Initial Exercise Date and prior to
the termination of the Option (as provided in Section 6), subject to the
Optionee's agreement that any shares purchased upon exercise are subject to the
Company's repurchase rights set forth in Section 11. In no event shall the
Option be exercisable for more shares than the Number of Option Shares.

          4.2.  METHOD OF EXERCISE. Exercise of the Option shall be by written
notice to the Company which must state the election to exercise the Option, the
number of whole shares of Stock for which the Option is being exercised and such
other representations and agreements as to the Optionee's investment intent with
respect to such shares as may be required pursuant to the provisions of this
Option Agreement. The written notice must be signed by the Optionee and must be
delivered in person, by certified or registered mail, return receipt requested,
by confirmed facsimile transmission, or by such other means as the Company may
permit, to the Chief Financial Officer of the Company, or other authorized
representative of the Participating Company Group, prior to the termination of
the Option as set forth in Section 6, accompanied by (i) full payment of the
aggregate Exercise Price for the number of shares of Stock being purchased and
(ii) an executed copy, if required herein, of the then current forms of escrow
and security agreement referenced below. The Option shall be deemed to be
exercised upon receipt by the Company of such written notice, the aggregate
Exercise Price, and, if required by the Company, such executed agreements.

          4.3.  PAYMENT OF EXERCISE PRICE.

                                        3
<Page>

                (a) FORMS OF CONSIDERATION AUTHORIZED. Except as otherwise
provided below, payment of the aggregate Exercise Price for the number of shares
of Stock for which the Option is being exercised shall be made (i) in cash, by
check, or cash equivalent, (ii) by tender to the Company of whole shares of
Stock owned by the Optionee having a Fair Market Value (as determined by the
Company without regard to any restrictions on transferability applicable to such
stock by reason of federal or state securities laws or agreements with an
underwriter for the Company) not less than the aggregate Exercise Price, (iii)
by means of a Cashless Exercise, as defined in Section 4.3(c), (iv) in the
Company's sole discretion at the time the Option is exercised, by the Optionee's
promissory note for the aggregate Exercise Price, or (v) by any combination of
the foregoing.

                (b) TENDER OF STOCK. Notwithstanding the foregoing, the Option
may not be exercised by tender to the Company of shares of Stock to the extent
such tender of Stock would constitute a violation of the provisions of any law,
regulation or agreement restricting the redemption of the Company's stock. The
Option may not be exercised by tender to the Company of shares of Stock unless
such shares either have been owned by the Optionee for more than six (6) months
or were not acquired, directly or indirectly, from the Company.

                (c) CASHLESS EXERCISE. A "CASHLESS EXERCISE" means the
assignment in a form acceptable to the Company of the proceeds of a sale or loan
with respect to some or all of the shares of Stock acquired upon the exercise of
the Option pursuant to a program or procedure approved by the Company
(including, without limitation, through an exercise complying with the
provisions of Regulation T as promulgated from time to time by the Board of
Governors of the Federal Reserve System). The Company reserves, at any and all
times, the right, in the Company's sole and absolute discretion, to decline to
approve or terminate any such program or procedure.

                (d) PAYMENT BY PROMISSORY NOTE. No promissory note shall be
permitted if an exercise of the Option using a promissory note would be a
violation of any law. The promissory note permitted in clause (iv) of Section
4.3(a) shall be a full recourse note in a form satisfactory to the Company, with
principal payable no more than four (4) years after the date the Option is
exercised. Interest on the principal balance of the promissory note shall be
payable in annual installments at the minimum interest rate necessary to avoid
imputed interest pursuant to all applicable sections of the Code. Such recourse
promissory note shall be secured by the shares of Stock acquired pursuant to the
then current form of security agreement as approved by the Company. At any time
the Company is subject to the regulations promulgated by the Board of Governors
of the Federal Reserve System or any other governmental entity affecting the
extension of credit in connection with the Company's securities, any promissory
note shall comply with such applicable regulations, and the Optionee shall pay
the unpaid principal and accrued interest, if any, to the extent necessary to
comply with such applicable regulations. Except as the Company in its sole
discretion shall determine, the Optionee shall pay the unpaid principal balance
of the promissory note and any accrued interest thereon upon termination of the
Optionee's Service with the Participating Company Group for any reason, with or
without cause.

          4.4.  TAX WITHHOLDING. At the time the Option is exercised, in whole
or in part, or at any time thereafter as requested by the Company, the Optionee
hereby authorizes

                                        4
<Page>

withholding from payroll and any other amounts payable to the Optionee, and
otherwise agrees to make adequate provision for (including by means of a
Cashless Exercise to the extent permitted by the Company), any sums required to
satisfy the federal, state, local and foreign tax withholding obligations of the
Participating Company Group, if any, which arise in connection with the Option,
including, without limitation, obligations arising upon (i) the exercise, in
whole or in part, of the Option, (ii) the transfer, in whole or in part, of any
shares acquired upon exercise of the Option, (iii) the operation of any law or
regulation providing for the imputation of interest, or (iv) the lapsing of any
restriction with respect to any shares acquired upon exercise of the Option. The
Optionee is cautioned that the Option is not exercisable unless the tax
withholding obligations of the Participating Company Group are satisfied.
Accordingly, the Optionee may not be able to exercise the Option when desired
even though the Option is vested, and the Company shall have no obligation to
issue a certificate for such shares or release such shares from any escrow
provided for herein.

          4.5.  CERTIFICATE REGISTRATION. Except in the event the Exercise Price
is paid by means of a Cashless Exercise, the certificate for the shares as to
which the Option is exercised shall be registered in the name of the Optionee,
or, if applicable, in the names of the heirs of the Optionee.

          4.6.  RESTRICTIONS ON GRANT OF THE OPTION AND ISSUANCE OF SHARES. The
grant of the Option and the issuance of shares of Stock upon exercise of the
Option shall be subject to compliance with all applicable requirements of
federal, state or foreign law with respect to such securities. The Option may
not be exercised if the issuance of shares of Stock upon exercise would
constitute a violation of any applicable federal, state or foreign securities
laws or other law or regulations or the requirements of any stock exchange or
market system upon which the Stock may then be listed. In addition, the Option
may not be exercised unless (i) a registration statement under the Securities
Act shall at the time of exercise of the Option be in effect with respect to the
shares issuable upon exercise of the Option or (ii) in the opinion of legal
counsel to the Company, the shares issuable upon exercise of the Option may be
issued in accordance with the terms of an applicable exemption from the
registration requirements of the Securities Act. THE OPTIONEE IS CAUTIONED THAT
THE OPTION MAY NOT BE EXERCISED UNLESS THE FOREGOING CONDITIONS ARE SATISFIED.
ACCORDINGLY, THE OPTIONEE MAY NOT BE ABLE TO EXERCISE THE OPTION WHEN DESIRED
EVEN THOUGH THE OPTION IS VESTED. The inability of the Company to obtain from
any regulatory body having jurisdiction the authority, if any, deemed by the
Company's legal counsel to be necessary to the lawful issuance and sale of any
shares subject to the Option shall relieve the Company of any liability in
respect of the failure to issue or sell such shares as to which such requisite
authority shall not have been obtained. As a condition to the exercise of the
Option, the Company may require the Optionee to satisfy any qualifications that
may be necessary or appropriate, to evidence compliance with any applicable law
or regulation and to make any representation or warranty with respect thereto as
may be requested by the Company.

          4.7.  FRACTIONAL SHARES. The Company shall not be required to issue
fractional shares upon the exercise of the Option.

     5.   NONTRANSFERABILITY OF THE OPTION. The Option may be exercised during
the lifetime of the Optionee only by the Optionee or the Optionee's guardian or
legal representative and may not be assigned or transferred in any manner except
by will or by the laws of descent and

                                        5
<Page>

distribution. Following the death of the Optionee, the Option, to the extent
provided in Section 7, may be exercised by the Optionee's legal representative
or by any person empowered to do so under the deceased Optionee's will or under
the then applicable laws of descent and distribution.

     6.   TERMINATION OF THE OPTION. The Option shall terminate and may no
longer be exercised on the first to occur of (a) the Option Expiration Date, (b)
the last date for exercising the Option following termination of the Optionee's
Service as described in Section 7, or (c) a Transfer of Control to the extent
provided in Section 8.

     7.   EFFECT OF TERMINATION OF SERVICE.

          7.1.  OPTION EXERCISABILITY.

                (a) DISABILITY. If the Optionee's Service with the Participating
Company Group is terminated because of the Disability of the Optionee, the
Option, to the extent unexercised and exercisable on the date on which the
Optionee's Service terminated, may be exercised by the Optionee (or the
Optionee's guardian or legal representative) at any time prior to the expiration
of six (6) months after the date on which the Optionee's Service terminated, but
in any event no later than the Option Expiration Date.

                (b) DEATH. If the Optionee's Service with the Participating
Company Group is terminated because of the death of the Optionee, the Option, to
the extent unexercised and exercisable on the date on which the Optionee's
Service terminated, may be exercised by the Optionee (or the Optionee's legal
representative, or other person who acquired the right to exercise the Option by
reason of the Optionee's death) at any time prior to the expiration of six (6)
months after the date on which the Optionee's Service terminated, but in any
event no later than the Option Expiration Date. The Optionee's Service shall be
deemed to have terminated on account of death if the Optionee dies within ninety
(90) days after the Optionee's termination of Service.

                (c) OTHER TERMINATION OF SERVICE. If the Optionee's Service with
the Participating Company Group terminates for any reason, except Disability or
death, the Option, to the extent unexercised and exercisable by the Optionee on
the date on which the Optionee's Service terminated, may be exercised by the
Optionee within ninety (90) days (or such other longer period of time as
determined by the Board, in its sole discretion) after the date on which the
Optionee's Service terminated, but in any event no later than the Option
Expiration Date.

          7.2.  ADDITIONAL LIMITATION ON OPTION EXERCISE. Except as the Company
and the Optionee otherwise agree, exercise of the Option pursuant to Section 7.1
following termination of the Optionee's Service may not be made by delivery of a
promissory note as provided in Section 4.3(a).

          7.3.  EXTENSION IF EXERCISE PREVENTED BY LAW. Notwithstanding the
foregoing, if the exercise of the Option within the applicable time periods set
forth in Section 7.1 is prevented by the provisions of Section 4.6, the Option
shall remain exercisable until three (3) months after the date the Optionee is
notified by the Company that the Option is exercisable, but in any event no
later than the Option Expiration Date.

                                        6
<Page>

          7.4.  EXTENSION IF OPTIONEE SUBJECT TO SECTION 16(b). Notwithstanding
the foregoing, if a sale within the applicable time periods set forth in Section
7.1 of shares acquired upon the exercise of the Option would subject the
Optionee to suit under Section 16(b) of the Exchange Act, the Option shall
remain exercisable until the earliest to occur of (i) the tenth (10th) day
following the date on which a sale of such shares by the Optionee would no
longer be subject to such suit, (ii) the one hundred and ninetieth (190th) day
after the Optionee's termination of Service, or (iii) the Option Expiration
Date.

          7.5.  LEAVE OF ABSENCE. For purposes of Section 7.1, the Optionee's
Service with the Participating Company Group shall not be deemed to terminate if
the Optionee takes any military leave, sick leave, or other bona fide leave of
absence approved by the Company of ninety (90) days or less. In the event of a
leave of absence in excess of ninety (90) days, the Optionee's Service shall be
deemed to terminate on the ninety-first (91st) day of such leave unless the
Optionee's right to reemployment with the Participating Company Group remains
guaranteed by statute or contract. Notwithstanding the foregoing, unless
otherwise designated by the Company (or required by law), a leave of absence
shall not be treated as Service for purposes of determining the Optionee's
vested shares.

     8.   TRANSFER OF CONTROL.

          8.1.  DEFINITIONS.

                (a) An "OWNERSHIP CHANGE EVENT" shall be deemed to have occurred
if any of the following occurs with respect to the Company:

                    (i)   the direct or indirect sale or exchange in a single or
series of related transactions by the shareholders of the Company of more than
fifty percent (50%) of the voting stock of the Company;

                    (ii)  a merger or consolidation in which the Company is a
party; or

                    (iii) the sale, exchange, or transfer of all or
substantially all of the assets of the Company; or

                    (iv)  a liquidation or dissolution of the Company.

                (b) A "TRANSFER OF CONTROL" shall mean an Ownership Change Event
or a series of related Ownership Change Events (collectively, the "TRANSACTION")
wherein the shareholders of the Company immediately before the Transaction do
not retain immediately after the Transaction, in substantially the same
proportions as their ownership of shares of the Company's voting stock
immediately before the Transaction, direct or indirect beneficial ownership of
more than fifty percent (50%) of the total combined voting power of the
outstanding voting stock of the Company or the corporation or corporations to
which the assets of the Company were transferred (the "TRANSFEREE
CORPORATION(S)"), as the case may be. For purposes of the preceding sentence,
indirect beneficial ownership shall include, without limitation, an interest
resulting from ownership of the voting stock of one or more corporations which,
as a result of the Transaction, own the Company or the Transferee
Corporation(s), as the

                                        7
<Page>

case may be, either directly or through one or more subsidiary corporations. The
Board shall have the right to determine whether multiple sales or exchanges of
the voting stock of the Company or multiple Ownership Change Events are related,
and its determination shall be final, binding and conclusive.

          8.2.  EFFECT OF TRANSFER OF CONTROL ON OPTION. In the event of a
Transfer of Control, the surviving, continuing, successor, or purchasing
corporation or parent corporation thereof, as the case may be (the "ACQUIRING
CORPORATION"), may either assume the Company's rights and obligations under the
Option or substitute for the Option a substantially equivalent option for the
Acquiring Corporation's stock. The Option shall terminate and cease to be
outstanding effective as of the date of the Transfer of Control to the extent
that the Option is neither assumed or substituted for by the Acquiring
Corporation in connection with the Transfer of Control nor exercised as of the
date of the Transfer of Control. Notwithstanding the foregoing, shares acquired
upon exercise of the Option prior to the Transfer of Control and any
consideration received pursuant to the Transfer of Control with respect to such
shares shall continue to be subject to all applicable provisions of this Option
Agreement except as otherwise provided herein. Furthermore, notwithstanding the
foregoing, if the corporation the stock of which is subject to the Option
immediately prior to an Ownership Change Event described in Section 8.1(a)(i)
constituting a Transfer of Control is the surviving or continuing corporation
and immediately after such Ownership Change Event less than fifty percent (50%)
of the total combined voting power of its voting stock is held by another
corporation or by other corporations that are members of an affiliated group
within the meaning of Section 1504(a) of the Code without regard to the
provisions of Section 1504(b) of the Code, the Option shall not terminate unless
the Board otherwise provides in its sole discretion.

     9.   ADJUSTMENTS FOR CHANGES IN CAPITAL STRUCTURE. In the event of any
stock dividend, stock split, reverse stock split, recapitalization, combination,
reclassification, or similar change in the capital structure of the Company,
appropriate adjustments shall be made in the number, Exercise Price and class of
shares of stock subject to the Option. If a majority of the shares which are of
the same class as the shares that are subject to the Option are exchanged for,
converted into, or otherwise become (whether or not pursuant to an Ownership
Change Event) shares of another corporation (the "New Shares"), the Board may
unilaterally amend the Option to provide that the Option is exercisable for New
Shares. In the event of any such amendment, the Number of Option Shares and the
Exercise Price shall be adjusted in a fair and equitable manner, as determined
by the Board, in its sole discretion. Notwithstanding the foregoing, any
fractional share resulting from an adjustment pursuant to this Section 9 shall
be rounded up or down to the nearest whole number, as determined by the Board,
and in no event may the Exercise Price be decreased to an amount less than the
par value, if any, of the stock subject to the Option. The adjustments
determined by the Board pursuant to this Section 9 shall be final, binding and
conclusive.

     10.  RIGHTS AS A SHAREHOLDER, EMPLOYEE OR CONSULTANT. The Optionee shall
have no rights as a shareholder with respect to any shares covered by the Option
until the date of the issuance of a certificate for the shares for which the
Option has been exercised (as evidenced by the appropriate entry on the books of
the Company or of a duly authorized transfer agent of the Company). No
adjustment shall be made for dividends, distributions or other rights for which
the record date is prior to the date such certificate is issued, except as
provided in Section 9.

                                        8
<Page>

Nothing in this Option Agreement shall confer upon the Optionee any right to
continue in the Service of a Participating Company or interfere in any way with
any right of the Participating Company Group to terminate the Optionee's Service
as an Employee or Consultant, as the case may be, at any time.

     11.  RIGHT OF FIRST REFUSAL.

          11.1. GRANT OF RIGHT OF FIRST REFUSAL. Except as provided in Section
11.7 below, in the event the Optionee, the Optionee's legal representative, or
other holder of shares acquired upon exercise of the Option proposes to sell,
exchange, transfer, pledge, or otherwise dispose of any shares acquired upon
exercise of the Option (the "TRANSFER SHARES") to any person or entity,
including, without limitation, any shareholder of the Participating Company
Group, the Company shall have the right to repurchase the Transfer Shares under
the terms and subject to the conditions set forth in this Section 11 (the "RIGHT
OF FIRST REFUSAL").

          11.2. NOTICE OF PROPOSED TRANSFER. Prior to any proposed transfer of
the Transfer Shares, the Optionee shall give a written notice (the "TRANSFER
NOTICE") to the Company describing fully the proposed transfer, including the
number of Transfer Shares, the name and address of the proposed transferee (the
"PROPOSED TRANSFEREE") and, if the transfer is voluntary, the proposed transfer
price, and containing such information necessary to show the bona fide nature of
the proposed transfer. In the event of a bona fide gift or involuntary transfer,
the proposed transfer price shall be deemed to be the Fair Market Value of the
Transfer Shares, as determined by the Board in good faith. If the Optionee
proposes to transfer any Transfer Shares to more than one Proposed Transferee,
the Optionee shall provide a separate Transfer Notice for the proposed transfer
to each Proposed Transferee. The Transfer Notice shall be signed by both the
Optionee and the Proposed Transferee and must constitute a binding commitment of
the Optionee and the Proposed Transferee for the transfer of the Transfer Shares
to the Proposed Transferee subject only to the Right of First Refusal.

          11.3. BONA FIDE TRANSFER. If the Company determines that the
information provided by the Optionee in the Transfer Notice is insufficient to
establish the bona fide nature of a proposed voluntary transfer, the Company
shall give the Optionee written notice of the Optionee's failure to comply with
the procedure described in this Section 11, and the Optionee shall have no right
to transfer the Transfer Shares without first complying with the procedure
described in this Section 11. The Optionee shall not be permitted to transfer
the Transfer Shares if the proposed transfer is not bona fide.

          11.4. EXERCISE OF RIGHT OF FIRST REFUSAL. If the Company determines
the proposed transfer to be bona fide, the Company shall have the right to
purchase all, but not less than all, of the Transfer Shares (except as the
Company and the Optionee otherwise agree) at the purchase price and on the terms
set forth in the Transfer Notice by delivery to the Optionee of a notice of
exercise of the Right of First Refusal within thirty (30) days after the date
the Transfer Notice is delivered to the Company. The Company's exercise or
failure to exercise the Right of First Refusal with respect to any proposed
transfer described in a Transfer Notice shall not affect the Company's right to
exercise the Right of First Refusal with respect to any proposed transfer
described in any other Transfer Notice, whether or not such other Transfer
Notice is issued by the Optionee or issued by a person other than the Optionee
with respect to a proposed transfer to the

                                        9
<Page>

same Proposed Transferee. If the Company exercises the Right of First Refusal,
the Company and the Optionee shall thereupon consummate the sale of the Transfer
Shares to the Company on the terms set forth in the Transfer Notice within sixty
(60) days after the date the Transfer Notice is delivered to the Company (unless
a longer period is offered by the Proposed Transferee); provided, however, that
in the event the Transfer Notice provides for the payment for the Transfer
Shares other than in cash, the Company shall have the option of paying for the
Transfer Shares by the present value cash equivalent of the consideration
described in the Transfer Notice as reasonably determined by the Company. For
purposes of the foregoing, cancellation of any indebtedness of the Optionee to
any Participating Company shall be treated as payment to the Optionee in cash to
the extent of the unpaid principal and any accrued interest canceled.

          11.5. FAILURE TO EXERCISE RIGHT OF FIRST REFUSAL. If the Company fails
to exercise the Right of First Refusal in full (or to such lesser extent as the
Company and the Optionee otherwise agree) within the period specified in Section
11.4 above, the Optionee may conclude a transfer to the Proposed Transferee of
the Transfer Shares on the terms and conditions described in the Transfer
Notice, provided such transfer occurs not later than ninety (90) days following
delivery to the Company of the Transfer Notice. The Company shall have the right
to demand further assurances from the Optionee and the Proposed Transferee (in a
form satisfactory to the Company) that the transfer of the Transfer Shares was
actually carried out on the terms and conditions described in the Transfer
Notice. No Transfer Shares shall be transferred on the books of the Company
until the Company has received such assurances, if so demanded, and has approved
the proposed transfer as bona fide. Any proposed transfer on terms and
conditions different from those described in the Transfer Notice, as well as any
subsequent proposed transfer by the Optionee, shall again be subject to the
Right of First Refusal and shall require compliance by the Optionee with the
procedure described in this Section 11.

          11.6. TRANSFEREES OF TRANSFER SHARES. All transferees of the Transfer
Shares or any interest therein, other than the Company, shall be required as a
condition of such transfer to agree in writing (in a form satisfactory to the
Company) that such transferee shall receive and hold such Transfer Shares or
interest therein subject to all of the terms and conditions of this Option
Agreement, including this Section 11 providing for the Right of First Refusal
with respect to any subsequent transfer. Any sale or transfer of any shares
acquired upon exercise of the Option shall be void unless the provisions of this
Section 11 are met.

          11.7. TRANSFERS NOT SUBJECT TO RIGHT OF FIRST REFUSAL. The Right of
First Refusal shall not apply to any transfer or exchange of the shares acquired
upon exercise of the Option if such transfer or exchange is in connection with
an Ownership Change Event. If the consideration received pursuant to such
transfer or exchange consists of stock of a Participating Company, such
consideration shall remain subject to the Right of First Refusal unless the
provisions of Section 11.9 below result in a termination of the Right of First
Refusal.

          11.8. ASSIGNMENT OF RIGHT OF FIRST REFUSAL. The Company shall have the
right to assign the Right of First Refusal at any time, whether or not there has
been an attempted transfer, to one or more persons as may be selected by the
Company.

          11.9. EARLY TERMINATION OF RIGHT OF FIRST REFUSAL. The other
provisions of this Option Agreement notwithstanding, the Right of First Refusal
shall terminate and be of no further force and effect upon (a) the occurrence of
a Transfer of Control, unless the Acquiring

                                       10
<Page>

Corporation assumes the Company's rights and obligations under the Option or
substitutes a substantially equivalent option for the Acquiring Corporation's
stock for the Option, or (b) the existence of a public market for the class of
shares subject to the Right of First Refusal. A "PUBLIC MARKET" shall be deemed
to exist if (i) such stock is listed on a national securities exchange (as that
term is used in the Exchange Act) or (ii) such stock is traded on the
over-the-counter market and prices therefor are published daily on business days
in a recognized financial journal.

     12.  ESCROW.

          12.1. ESTABLISHMENT OF ESCROW. To ensure that shares subject to the
Right of First Refusal or securing any promissory note will be available for
repurchase, the Company may require the Optionee to deposit the certificate
evidencing the shares which the Optionee purchases upon exercise of the Option
with an agent designated by the Company under the terms and conditions of escrow
and security agreements approved by the Company. If the Company does not require
such deposit as a condition of exercise of the Option, the Company reserves the
right at any time to require the Optionee to so deposit the certificate in
escrow. Upon the occurrence of an Ownership Change Event or a change, as
described in Section 9, in the character or amount of any of the outstanding
stock of the corporation the stock of which is subject to the provisions of this
Option Agreement, any and all new, substituted or additional securities or other
property to which the Optionee is entitled by reason of the Optionee's ownership
of shares of Stock acquired upon exercise of the Option that remain, following
such Ownership Change Event or change described in Section 9, subject to the
Right of First Refusal or any security interest held by the Company shall be
immediately subject to the escrow to the same extent as such shares of Stock
immediately before such event. The Company shall bear the expenses of the
escrow.

          12.2. DELIVERY OF SHARES TO OPTIONEE. As soon as practicable after the
expiration of the Right of First Refusal and after full repayment of any
promissory note secured by the shares or other property in escrow, but not more
frequently than twice each calendar year, the escrow agent shall deliver to the
Optionee the shares and any other property no longer subject to such restriction
and no longer securing any promissory note.

          12.3. NOTICES AND PAYMENTS. In the event the shares and any other
property held in escrow are subject to the Company's exercise of the Right of
First Refusal, the notices required to be given to the Optionee shall be given
to the escrow agent, and any payment required to be given to the Optionee shall
be given to the escrow agent. Within thirty (30) days after payment by the
Company, the escrow agent shall deliver the shares and any other property which
the Company has purchased to the Company and shall deliver the payment received
from the Company to the Optionee.

     13.  STOCK DISTRIBUTIONS SUBJECT TO OPTION AGREEMENT. If, from time to
time, there is any stock dividend, stock split or other change, as described in
Section 9, in the character or amount of any of the outstanding stock of the
corporation the stock of which is subject to the provisions of this Option
Agreement, then in such event any and all new, substituted or additional
securities to which the Optionee is entitled by reason of the Optionee's
ownership of the shares acquired upon exercise of the Option shall be
immediately subject to the Right of First Refusal and any security interest held
by the Company with the same force and effect as the

                                       11
<Page>

shares subject to the Right of First Refusal and such security interest
immediately before such event.

     14.  LEGENDS. The Company may at any time place legends referencing the
Right of First Refusal, and any applicable federal, state or foreign securities
law restrictions on all certificates representing shares of stock subject to the
provisions of this Option Agreement. The Optionee shall, at the request of the
Company, promptly present to the Company any and all certificates representing
shares acquired pursuant to the Option in the possession of the Optionee in
order to carry out the provisions of this Section. Unless otherwise specified by
the Company, legends placed on such certificates may include, but shall not be
limited to, the following:

          14.1. "THE SECURITIES EVIDENCED BY THIS CERTIFICATE HAVE NOT BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE SOLD,
TRANSFERRED, ASSIGNED OR HYPOTHECATED UNLESS THERE IS AN EFFECTIVE REGISTRATION
STATEMENT UNDER SUCH ACT COVERING SUCH SECURITIES, THE SALE IS MADE IN
ACCORDANCE WITH RULE 144 OR RULE 701 UNDER THE ACT, OR THE COMPANY RECEIVES AN
OPINION OF COUNSEL FOR THE HOLDER OF THESE SECURITIES REASONABLY SATISFACTORY TO
THE COMPANY, STATING THAT SUCH SALE, TRANSFER, ASSIGNMENT OR HYPOTHECATION IS
EXEMPT FROM THE REGISTRATION AND PROSPECTUS DELIVERY REQUIREMENTS OF SUCH ACT."

          14.2. Any legend required to be placed thereon by the Commissioner of
Corporations of the State of California.

          14.3. "THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO A
RIGHT OF FIRST REFUSAL OPTION IN FAVOR OF THE CORPORATION OR ITS ASSIGNEE SET
FORTH IN AN AGREEMENT BETWEEN THE CORPORATION AND THE REGISTERED HOLDER, OR SUCH
HOLDER'S PREDECESSOR IN INTEREST, A COPY OF WHICH IS ON FILE AT THE PRINCIPAL
OFFICE OF THIS CORPORATION."

     15.  PUBLIC OFFERING. The Optionee hereby agrees that in the event of any
underwritten public offering of stock, including an initial public offering of
stock, made by the Company pursuant to an effective registration statement filed
under the Securities Act, the Optionee shall not offer, sell, contract to sell,
pledge, hypothecate, grant any option to purchase or make any short sale of, or
otherwise dispose of any shares of stock of the Company or any rights to acquire
stock of the Company for such period of time from and after the effective date
of such registration statement as may be established by the underwriter for such
public offering; provided, however, that such period of time shall not exceed
one hundred eighty (180) days from the effective date of the registration
statement to be filed in connection with such public offering. The foregoing
limitation shall not apply to shares registered in the public offering under the
Securities Act. The Optionee shall be subject to this Section provided and only
if the officers and directors of the Company are also subject to similar
arrangements.

     16.  BINDING EFFECT. Subject to the restrictions on transfer set forth
herein, this Option Agreement shall inure to the benefit of and be binding upon
the parties hereto and their

                                       12
<Page>

respective heirs, executors, administrators, successors and assigns.

     17.  TERMINATION OR AMENDMENT. The Board may terminate or amend the Plan or
the Option at any time; provided, however, that except as provided in Section
8.2 in connection with a Transfer of Control, no such termination or amendment
may adversely affect the Option or any unexercised portion hereof without the
consent of the Optionee unless such termination or amendment is necessary to
comply with any applicable law or government regulation. No amendment or
addition to this Option Agreement shall be effective unless in writing.

     18.  INTEGRATED AGREEMENT. This Option Agreement and the Plan constitute
the entire understanding and agreement of the Optionee and the Participating
Company Group with respect to the subject matter contained herein and therein
and there are no agreements, understandings, restrictions, representations, or
warranties among the Optionee and the Participating Company Group with respect
to such subject matter other than those as set forth or provided for herein or
therein. To the extent contemplated herein or therein, the provisions of this
Option Agreement shall survive any exercise of the Option and shall remain in
full force and effect.

     19.  APPLICABLE LAW. This Option Agreement shall be governed by the laws of
the State of California as such laws are applied to agreements between
California residents entered into and to be performed entirely within the State
of California.

                                            MITOKOR

                                            By:
                                               ---------------------------------

                                            Title:
                                                  ------------------------------

     The Optionee represents that the Optionee is familiar with the terms and
provisions of this Option Agreement, including the Right of First Refusal set
forth in Section 11, and hereby accepts the Option subject to all of the terms
and provisions thereof. The Optionee hereby agrees to accept as binding,
conclusive and final all decisions or interpretations of the Board upon any
questions arising under this Option Agreement. The undersigned acknowledges
receipt of a copy of the Plan.

                                            OPTIONEE

Date:
     ---------------------------------      -------------------------------

                                       13

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