Quiz 10 Key
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1-2. Answer with (A) amplification occurs in this step; (L) allosteric activation occurs in this step; or (I) this is an inactivation. This is for the Gs pathway. Answer with only one letter.

     A        AC synthesizes cAMP.

     I        Cyclic phosphodiesterase adds H2O to
               cAMP.

  L, A   The receptor activates Gα.

     I        2 C + R2 → R2C2.

     I        Gβγ binds Gα.

     L        cAMP activates PKA.

     L        Gα activates AC.

     A        PKA activates phosphorylase kinase.

3-4. For the key, I've rearranged the numbers so that each Keq has the corresponding ΔG°′ value immediately below. All Keq values less than 1.0 (and ΔG°′ values that are positive) are unfavorable, or not spontaneous. All Keq values greater than 1.0 (and ΔG°′ values that are negative) are spontaneous. Having Keq = 1 is neither unfavorable nor favorable.

Keq

1 x 10−3

6.4 x 10−3

0.36

1.0

1.001

25

2.2 x 105

ΔG°′ (J/mol)

+ 17,000

+12,500

+2500

0

− 2.5

− 8,000

− 30,500

5-6. Underline the two products of the unfavorable (not spontaneous) reaction if these combine in a redox reaction.

acetaldehyde + 2 H+ + 2 e−   → ethanol

E°′ = − 0.346 V

ubiquinone + 2 H+ + 2 e−   → ubiquinol

E°′ = 0.045 V

5-6. Underline the two products of the unfavorable (not spontaneous) reaction if these combine in a redox reaction.

NAD+ + 2 H+ + 2 e−   → NADH + H+

E°′ = − 0.320 V

fumarate + 2 H+ + 2 e−   → succinate

E°′ = 0.031 V

5-6. Use these two half reactions. Underline the two products for the spontaneous reaction.

NAD+ + 2 H+ + 2 e−   → NADH + H+

E°′ = − 0.320 V

oxaloacetate + 2 H+ + 2 e−   → malate

E°′ = − 0.166 V

5-6. Use these two half reactions. Underline the two products for the spontaneous reaction.

pyruvate + 2 H+ + 2 e−   → lactate

E°′ = − 0.185 V

acetaldehyde + 2 H+ + 2 e−   → ethanol

E°′ = − 0.346 V

7-10. Use (H) hexokinase; (P) PFK-1; (G) GAP dehydrogenase; or (Y) pyruvate kinase.
For most quiz versions, you were supposed to use each choice once.

      P       Fructose-P is its substrate.

      G       an oxidoreductase

   H, P     occurs during the preparation phase

    H, P, Y      a transferase

     Y        PEP is its substrate.

     H, P    ATP → ADP

     P        Fructose-1,6-bis-P is its product.

     Y        ADP → ATP

   G, Y    occurs during the payoff phase

     G        NAD+ → NADH

     G        requires HPO42− as a substrate

     H        Glucose is its substrate.

 

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