Cofactors

Question 1

What are the two types of cofactors used by enzymes

Answer 1

inorganic ions (Mg2+, Fe2+, Mn2+, etc.)
coenzymes

Question 2

What are coenzymes

Answer 2

complex organic or metalloorganic compounds that act as transient carriers of specific functional groups

Question 3

Many cofactors are derivatives of ________________

Answer 3

adenosine

Question 4

What is the carrier/donor of phosphate groups

Answer 4

ATP

Question 5

What is the function of ATP at the cellular level (what is it doing to other molecules)

Answer 5

phosphorylate other molecules

Question 6

What is the coenzyme that acts as a carrier of acyl (acid) groups

Answer 6

coenzyme A

Question 7

What is coenzyme A derived from

Answer 7

pantothenic acid (B5)

Question 8

Looking at the structure of coenzyme A (CoA/CoASH) what is the general feature of its structure

Answer 8

horizontal and very long

Question 9

CoASH (coenzyme A) forms ________________ derivatives with organic acids

Answer 9

thioester (sulphur analogue of an ester)

Question 10

What is the name for the thioester derivative formed by CoASH and organic acids

Answer 10

acyl CoA

Question 11

In the specific case of acetic acid, what is the name of the thioester derivative formed by CoASH

Answer 11

acetyl CoA

Question 12

What are NAD+, NADP+, FAD, and FMN used for

Answer 12

universal electron carriers

Question 13

Why is it important that NAD+, NADP+, FAD and FMN act as universal electron carriers

Answer 13

electrons are removed from the substrates and transferred onto these cofactors, reducing them, and conserving the energy of oxidation

Question 14

Which of NAD+, NADP+, FAD, and FMN are involved in beta oxidation

Answer 14

NAD+ and FAD

Question 15

NAD+ and NADP+ are the _________________ nucleotides

Answer 15

pyridine

Question 16

What are NAD+ and NADP derived from

Answer 16

niacin (B3)

Question 17

Looking at the structure of the pyridine nucleotides, what is the general feature of its structure

Answer 17

Have a pyridine ring, and are two structures stacked on top of one another connected by a phosphate backbone looking structure

Question 18

During oxidation of NAD+ and NADP+, ____ _____________ atoms are removed from the substrate

Answer 18

2 hydrogen atoms

Question 19

The oxidized form of NAD+ and NADP+ accept a ___________ ion to become reduced

Answer 19

hydride
the other hydrogen is just released into the aqueous environment

Question 20

NAD+ is used as the ______________ agent in catabolic processes

Answer 20

oxidizing agent

Question 21

NADPH is used as the ______________ agent in biosynthesis

Answer 21

reducing agent

Question 22

If NAD+ is used as the oxidizing agent (being reduced), where is it reoxidized

Answer 22

in the electron transport chain

Question 23

FAD and FMN are the _______________ nucleotides

Answer 23

flavin

Question 24

FAD and FMN are derived from __________________

Answer 24

riboflavin (B2)

Question 25

Flavin nucleotides usually act as ______________ groups; found tightly bound to the enzyme

Answer 25

prosthetic

Question 26

Looking at the structure of FAD and FMN what is the general feature of its structure

Answer 26

vertical and very long

Question 27

Flavin nucleotides can accept either ____ or ____ electrons in the form of ____ or ____ ______________ atoms

Answer 27

accept either 1 or 2 electrons in the form of 1 or 2 hydrogen atoms

Question 28

What are the FULLY reduced forms of FAD and FMN

Answer 28

FADH2 and FMNH2

Question 29

What are the forms of FAD and FMN when only one electron is accepted (and one unpaired electron still exists) AND what is the name of these forms

Answer 29

FADH and FMNH *semiquinone radical forms*

Question 30

Why is there a greater diversity of reactions in FAD and FMN than in NAD and NADP

Answer 30

since FAD and FMN can accept either one or two electrons, there is a greater diversity of reactions possible when compared to the NAD(P)-linked dehydrogenases

Question 31

Cofactor CoA is the carrier of...

Answer 31

acids

Question 32

Pyridine cofactors are carriers of...

Answer 32

electron pairs

Question 33

Flavin cofactors are carriers of...

Answer 33

electrons (doesn't have to be pairs)

Question 34

CoA is derived from which B vitamin

Answer 34

B5 - pantothenic acid

Question 35

Pyridine are derived from which B vitamin

Answer 35

B3 - niacin

Question 36

Flavins are derived from which B vitamin

Answer 36

B2 - riboflavin