Lecture 8: Catalysts and enzymology

Question 1

the transition state is (less/ more) stable and acts as ____

Answer 1

the transition state is less stable and acts as an energy barrier

Question 2

energy of activation =?

Answer 2

= difference in energy from the ground state to the higher energy of the transition state [aka energy required for reaction to proceed]

Question 3

the larger the ΔG°‡ the (faster/ slower) the velocity of the reaction and a (bigger/ smaller) K

Answer 3

the larger the ΔG°‡ the slower the velocity of the reaction and a smaller K

Question 4

enzymes can change _____ (1) but cannot change _____ (2)

Answer 4

can change ΔG°‡ [and the rate constant, K]; can’t change Keq or ΔG°

Question 5

enzymes lower the activation energy (ΔG°‡) by ___ (2)

Answer 5

• stabilizing the transition state [lower the hill]
  or
• destabilizing the ground state [raise the valley]

Question 6

ΔΔG°‡ = ?
ΔG°‡ = ?
ΔG° = ?

Answer 6

ΔΔG°‡ = measure of efficiency for an enzyme
ΔG°‡ = difference between reactants and products relative to transition state
ΔG° = difference between reactants and products [independent of catalyst]

Question 7

higher K = (faster/ slower) rate

Answer 7

higher K = faster rate

Question 8

initial velocity on a graph of concentration/time is shown by _____

Answer 8

Vo, tangent of the curve

Question 9

at high [S], V becomes _____

Answer 9

at high [S], V becomes independent of [S] [zero order]

Question 10

increasing [E] does what to Vmax?

Answer 10

creates a new Vmax