2.2 Mechanisms of Enzyme activity

Question 1

Coenzyme vs cofactor

Question 2

Induced fit vs lock and key model. Which one is more scientifically accepted (and more likely to see on test day)?

Answer 2

Induced fit model

Question 3

What is the term used to describe the molecule which an enzyme acts on?

Answer 3

Substrate

Question 4

Term used to describe physical interaction between enzyme and molecule

Answer 4

Enzyme-substrate complex

Question 5

What is an active site

Answer 5

Site on enzyme which the substrate is held during a chemical reaction

Question 6

Is alteration of tertiary or quaternary structure required for lock and key model?

Answer 6

No

Question 7

Briefly describe the induced-fit model

Answer 7

• Substrate changes conformation of substrate
• Requires energy (endergonic)
• Release releases energy (exergonic)

Question 8

Define apoenzymes

Answer 8

Enzymes without their cofactors

Question 9

Define holoenzymes

Answer 9

Enzymes that have cofactors attached to them

Question 10

How are cofactors attached to the enzymes?

Answer 10

varies; from non-covalent to covalent

Question 11

What are prosthetic groups

Answer 11

Tightly bound cofactors that is required for enzyme function

Question 12

Name the non-protein molecule required for some enzymes to function

Answer 12

Cofactor/coenzyme

Question 13

Cofactors

Answer 13

• Generally inorganic molecules
• Vitamins or derivatives of vitamins

Question 14

Coenzymes

Answer 14

• Small, organic groups

Question 15

Two examples of water-soluble vitamins. Their properties?

Answer 15

1. B complex vitamins
2. Ascorbic acid

• Easily excreted

Question 16

List four fat soluble proteins

Answer 16

A, D, E, K

Question 17

Are enzymatic reactions restricted to a single cofactor?

Answer 17

No.