10: Glycogen Metabolism

Question 1

Where is most of glycogen stored?

Answer 1

liver

Question 2

What is the advantage of glycogen being branched?

Answer 2

it can be broken off quickly

Question 3

When is liver glycogen the lowest?

Answer 3

during meals

Question 4

What enzyme converts glucose molecules to glucose 1-phosphate?

Answer 4

glycogen phosphorylase

Question 5

What is glucose 6-phosphate converted to in the liver?

Answer 5

glucose

Question 6

What is glucose 6-phosphate converted to in non-liver cells?

Answer 6

pyruvate (by glycolysis)

Question 7

Glycogen debranching enzymes

Answer 7

removes parts of glycogen branches and transfers them to a linear branch

Question 8

UTP

Answer 8

uridine triphosphate (nucleotide)

Question 9

What enzyme converts UDP-glucose to UDP to create glycogen?

Answer 9

glycogen synthase

Question 10

Glycogen branching enzyme

Answer 10

Can add branches to glycogen molecules

Question 11

What enzyme is activated during glycogen synthesis?

Answer 11

glycogen synthase

Question 12

What enzyme is activated when glycogen breakdown occurs?

Answer 12

glycogen phosphorylase

Question 13

What amino acid is attached to glycogen synthase?

Answer 13

serine

Question 14

What molecule is the storage signal for glycogen?

Answer 14

insulin

Question 15

What molecules are the breakdown signal for glycogen?

Answer 15

glucagon and epinephrine

Question 16

What enzyme converts ATP to ADP, favoring glycogen breakdown?

Answer 16

protein kinases

Question 17

What enzyme converts H2O to Pi, favoring glycogen synthesis?

Answer 17

protein phosphatases

Question 18

What enzyme does insulin activate?

Answer 18

protein phosphatases

Question 19

What cycle does glucagon and epinephrine activate?

Answer 19

cAMP and PKA

Question 20

What does the cAMP and PKA pathway activate?

Answer 20

protein kinases

Question 21

What does a mutation in the glycogen synthase gene (GSY1) cause?

Answer 21

glycogen synthase is not correctly regulated, causing an “always on” state and too much production of glycogen/glucose

Question 22

Where does the pentose phosphate pathway occur?

Answer 22

cytoplasm

Question 23

What enzymes are used in the pentose phosphate pathway to generate NADPH?

Answer 23

dehydrogenases

Question 24

What molecule can be made into ribose 5-phosphate for nucleotide synthesis?

Answer 24

ribulose 5-phosphate

Question 25

What does a deficiency of glucose 6-phosphate dehydrogenase cause?

Answer 25

More oxidative damage to cells