Describe energy coupling How does an enzyme speed up a reaction? What occurs when a substrate binds to an enzyme? Way that enzymes lower the required activation energy Cofactor competitive substrate v

1. Describe energy coupling

• Using energy to drive something else
• Using an exergonic reaction to fuel an endergonic reaction
o Process with a negative Delta G that is greater than the positive delta G to make the process spontaneous

2. How does an enzyme speed up a reaction?

decrease the required activation energy

3. What occurs when a substrate binds to an enzyme?

• Active site, cooperativity - enzyme closes around substrate a little more

4. Way that enzymes lower the required activation energy

C - covalently bound
O - orienting substrates together
P - Providing a favorable environment
S - Stress

5. Cofactor

• Non-protein enzyme helper for catalytic activity
• Can be vitamins or metals

6. competitive substrate v. noncompetitive

• Competitive inhibitor binds at the active site
• Noncompetive - binds anywhere away from the active site
o Usually changes shape
o EX CO2

7. Cofactor or a noncompetitve inhibtor can both cause what kind of reaction

Allosteric
Allo - other
Steric - place

8. Allosteric reaction control

o Allo - other
o Steric - place
o Binds away from the active site and causes some kind of a change
Needs to be in order to be allostaric
o Can be positive or negative
o If something binds to one site then it helps activate the other site

9. Binding of ____ stabilizes the shape of an enzyme in the active state

activator

10. ____ stabilizes the inactive form of an enzyme

inhibitor

11. Feedback inhibition

final product of the reactions acts as an inhibitor for a reaction
- aka negative feedback reaction

12. a) ΔS is positive and ΔH is negative

most spontaneous (giving off the most energy)

13. b) ΔS is negative and ΔH is positive

non-spontaneous (decreasing the entropy)

14. c) ΔS is positive and ΔH is positive

you want a high temperature (will make it spontaneous)

15. d) ΔS is negative and ΔH is negative

you want temperature really low to be spontaneous