Energy and Enzymes Flashcards Preview

BIOL 141 > Energy and Enzymes > Flashcards

Flashcards in Energy and Enzymes Deck (17):
1

Enthalpy

H

the total energy of a system

2

Free energy

G

the usable amount of free energy in a system

3

Entropy

S

the amount of disorder

4

Equation that relates energy in a system

G = H -TS

5

What does T stand for?

Absolute temperature in kelvins

6

When is a reaction spontaneous?

when it is exergonic

there is a lowering of free energy in the system

7

What indicates a lowering of free energy?

negative delta G

8

How can T be manipulated to make a reaction spontaneous?

If H and S are both positive, T can be raised

If H and S are both negative, T can be lowered

9

Activation energy

the energy needed to reach the transition state of the reaction

10

What do enzymes do?

decrease the amount of activation energy

this speeds up the rate of the reaction

11

What are the three phases of enzyme activity?

1. Initiation: reactants bind to the active site

2. Transition state facilitation: the amount of activation energy needed is lowered

3. Termination: the reactants are released

12

Competitive inhibition

Substrates cannot bind when a regulatory molecule binds to the ACTIVE SITE

13

What is competitive inhibition dependent on?

concentrations

14

Allosteric regulation

regulatory molecule binds to a different site on the enzyme besides the active site

allosteric regulation can activate or deactivate an enzyme

induces a shape change which makes the substate no longer able to bind

15

Induced fit model

a better understanding of the enzyme than the lock and key model

the enzyme changes shape in order to fit the substrate

16

transition state

intermediate configuration

17

Endergonic

not spontaneous because you need an input of energy to start

this raises the amount of potential energy in a system

G is positive