Exam 4

Question 1

Why is the T state of glycogen phosphorylase less active?

Answer 1

the active site is partially blocked

Question 2

What physiological conditions render phophorylase b less active?

Answer 2

high ATP and high G6P levels

Question 3

In muscle, the first event in the breakdown of glycogen due to binding of a hormone is that

Answer 3

G protein is activated

Question 4

Why is glycogen branching important?

Answer 4

branching increases the solubility of glycogen

Branching increases glycogen synthesis and degradation by increasing the potential sites of action

Question 5

Delta E is a measure of a molecule’s

Answer 5

ability to donate or accept electrons

Question 6

Complex I is a complex in the electron transport chain. This complex is most likely

Answer 6

amphilic

Question 7

A transcription factor

Answer 7

binds to DNA

Question 8

The SRP for NAD+/NADH redox =-0.32V thus, NADH is a

Answer 8

good electron donor

Question 9

The standard electron potential is a comparison of

Answer 9

the electron donating capability of a molecule relative to the H2/H+ redox couple

Question 10

When mitochondria are actively carrying out aerobic respiration, the pH of the matrix is

Answer 10

greater than the pH of the IMS

Question 11

The final reduced species in the electron transport chain is

Answer 11

H2O

Question 12

T/F

Cytochrome c only participates in one-electron transfers.

Answer 12

True

Question 13

What are the two main tissues that store glycogen

Answer 13

muscle and liver

Question 14

What does epinephrine do?

Answer 14

causes the phosphorylation of glycogen synthase a to make glycogen synthase b and causes the phosphorylation of glycogen phosphorylase b to make glycogen phoshphorylase a

Question 15

In terms of glycogen phosphoylase, of which form does most of the allosteric regulation exist?

Answer 15

b

Question 16

The purpose of glycogenin is

Answer 16

to prime for glycogen synthesis because glycogen synthase can only add UDPglucose to the glycogen chain if it contains more than 4 glucose molecules

Question 17

How is energy used to make ATP “stored” by the electron transport chain?

Answer 17

protons are non-spontaneously pumped into the unfavorable region, the intermembrane space

Question 18

The loss of the AMP-binding site in muscle glycogen phosphorylase could lead to

Answer 18

phosphorylase b will be inactive even when the AMP level is high. Hence, glycogen will not be degraded in the muscle unless glycogen phosphorylase is converted into the a form by a hormone induced pathway

Question 19

What would happen to a human if there was a mutation of Ser 14 to Ala 14 in its liver glycogen phosphorylase?

Answer 19

b cannot be converted into the much more active a form. Hence, the mobilization of liver glycogen will be markedly impaired

Question 20

CoQ is a mobile electron carrier in the ETC. It is most likely

Answer 20

hydrophobic

Question 21

Why can’t G1P leave the cell?

Answer 21

there is no membrane transporter for G1P

Question 22

The hemes on Complex IV are considered

Answer 22

prosthetic groups

Question 23

In general, transaminase catalyzes

Answer 23

a group transfer

Question 24

The glycerol 3 phosphate dehydrogenase shuttle provides

Answer 24

means to collect the electrons from NADH reduced in glycoslysis

Question 25

T/F

A typical muscle cell during rest will have more glycogen phosphorylase b and more glycogen synthase a

Answer 25

True

Question 26

What is the purpose of the Q cycle?

Answer 26

it allows for a mobile carrier of 2 electrons to donate them to an acceptor that only takes 1 electron

Question 27

A synthase generally catalyzes

Answer 27

a covalent bond formation

Question 28

When glucose levels are high ____ is released into the bloodstream, and when glucose levels are low ____ is released.

Answer 28

insulin, epinephrine

Question 29

What does insulin do?

Answer 29

activates GLUT4 receptors by making them more sensitive to glucose on fat and muscle cells

Question 30

The relative concentrations of ATP and ADP control the cellular rates of

Answer 30

transition reaction
ETC
glycolsysis

Question 31

What is unique about the active site of glycogen phosphorylase?

Answer 31

the active site is wide enough for approximately 5 glucose molecules to fit in the region

Question 32

What does insulin inhibit?

Answer 32

glycogen synthase kinase (GSK)

Question 33

What two metabolites are predicted to increase in skeletal muscle when fat becomes the major substrate oxidized?

Answer 33

acetyl CoA, citrate