Intro to Enzymes Pt.2

Question 1

A reaction is spontaneous when

Answer 1

Products have less energy than the reactants

The /\G is negative

Question 2

A reaction is not spontaneous when

Answer 2

Reactants have less energy than the products

The /\G is positive

Question 3

Enzymes increase reaction rates by

Answer 3

decreasing /\G+ (Activation Barriers)

Question 4

Steps in an enzymatic reaction (4)

Answer 4

1) Enzyme & substrate combine to form complex

2) Complex goes through transition state (not quite substrate or product)

3) A complex of enzyme & product is formed

4) Finally the enzyme and product separate

Question 5

Enzymes do not affect

Answer 5

equilibrium

Question 6

What are the characteristics (models) of enzyme active sites

Answer 6

Lock and Key Model

Induced-Fit Model

Question 7

Lock and Key Model

Answer 7

Only a substrate of the proper shape could fit with the enzyme

Question 8

Induced-Fit Model

Answer 8

Model assumes continuous changes in active site structures as a substrate binds

Question 9

The active site is a…

Answer 9

3D cleft or crevice formed by groups that come from different parts of the amino acid sequence

Question 10

Substrates are bound to enzymes by

Answer 10

multiple weak attractions

+ Electrostatic interactions

+ Hydrogen Bonds

+ Van der Waals Forces

Question 11

The specificity of binding depends on the

Answer 11

precisely defined arrangement of atoms in an active site