Cofactors and Coenzymes

Question 1

some enzymes require an additional nonprotein _____ group to function.

Answer 1

prosthetic

Question 2

In this case, the protein portion is called the _____, and the nonprotein group is called the _____

Answer 2

apoenzyme

cofactor

Question 3

Together they form the active enzyme called the

Answer 3

holoenzyme

Question 4

may be metal ions, organic compounds, or organometallic compounds, and must be bound to the enzyme to maintain the correct shape of the active site

Answer 4

cofactor

Question 5

Thus, these enzymes are only active when the

Answer 5

cofactor is bound to them

Question 6

Other enzymes require the temporary binding of a

Answer 6

coenzyme

Question 7

Such binding is generally mediated by weak interactions like

Answer 7

hydrogen bonding

Question 8

Coenzymes are organic molecules that serve as carriers of ____ or _____

Answer 8

electrons

chemical groups

Question 9

In chemical reactions, they may either ____ groups to the substrate or ____ groups that are removed from the substrate.

Answer 9

donate

accept

Question 10

Often, coenzymes contain _______ as part of their structure.

Answer 10

modified vitamin

Question 11

is an organic substance that is required in the diet in only small amounts.

Answer 11

vitamins

Question 12

Of the water-soluble vitamins, only vitamin ____has not been associated with a coenzyme

Answer 12

c

Question 13

Riboflavin (B2) coenzyme

Answer 13

Flavin mononucleotide (FMN)	
Flavin adenine dinucleotide (FAD)

Question 14

Riboflavin (B2) function

Answer 14

Carrier of H atoms

Question 15

Niacin (B3) coenzyme

Answer 15

Nicotinamide adenine dinucleotide (NAD+)

Nicotinamide adenine dinucleotide phosphate (NADP+)

Question 16

Niacin (B3) function

Answer 16

Carrier of hydride ions

Question 17

Pyridoxine (B6) coenzyme

Answer 17

Pyridoxal phosphate

Pyridoxamine phosphate

Question 18

Pyridoxine (B6) function

Answer 18

Carriers of amino and carboxyl groups

Question 19

Pantothenic acid coenzyme

Answer 19

coenzyme A

Question 20

Pantothenic acid function

Answer 20

Acyl group carrier

Question 21

is an example of a coenzyme that is of critical importance in the oxidation reactions of the cellular energy-harvesting processes.

Answer 21

Nicotinamide adenine dinucleotide (NAD+)

Question 22

NAD+ can accept a ____ ion, a hydrogen atom with ___electrons, from the substrate of these reactions.

Answer 22

hydride

2

Question 23

The substrate is oxidized, and NAD+ is reduced to produce

Answer 23

NADH

Question 24

The hydride ion carrier ___ and the hydrogen atom carrier ____ are also critical for the energy-harvesting reactions of the cell

Answer 24

NADP+

FAD

Question 25

NAD+ and NADP+ are derived from the vitamin

Answer 25

niacin

Question 26

FAD is made from the vitamin

Answer 26

riboflavin