1.12 Glycogen Metabolism Flashcards Preview

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Flashcards in 1.12 Glycogen Metabolism Deck (22):
0

Where is Glycogen mostly stored

In liver and muscle

1

Glycogen is degraded by removal of a terminal glucose from where?

the nonreducing end of a glycogen chain

2

What enzyme degrades the terminal glucose from the glycogen chain

Glycogen Phosphorylase

3

Glycogen metabolism is demonstrative of a hydrolysis or a phosphorolysis?

Phosphorolysis

4

At what point on the Glycogen chain does the enzyme stop removing terminal glucose molecules?

On the fourth residue from the branch point

5

After Glucose molecule is released from Glycogen chain, what structure is it?

Glucose 1-Phosphate

6

What enzyme converts Glucose 1-phosphate to Glucose 6-phosphate?

Phosphoglucomutase

7

What activates and prepares Glucose 1-phosphate to be added to the glycogen chain?

The activation and attachment of a sugar nucleotide
Ex: G1P + UTP --> UDP-Glucose

8

What enzyme catalyzes the addition of a sugar nucleotide to G1P

UDP-glucose pyrophosphorylase

9

What enzyme catalyzes the first step of glycogen synthese by converting G6P to G1P

Phosphoglucomutase

10

What enzyme catalyzes the addition of the glycosyl unit to the glycogen chain?

Glycogen Synthase

11

What happens to UDP during the addition of the glycosyl unit to the terminal end of the glycogen chain

It is displaced by the terminal Hydroxyl group of the growing glycogen molecule

12

T or F, The glycosyl residues can only be added to the glycogen chain if it already contains 4 residues

True

13

How is a branch made during Glycogen synthesis

Breaking of an alpha 1-4 link of a block of about six or seven glycosyl residues from the terminal nonreducing end. This block is transfered to a more interior residue on the C-6

14

What enzyme catalyzes the alpha 1-6 linkages found at branching sites

branching enzyme Glycosyl (4-6) transferase

15

Role of Glycogenin

Acts as a primer for new branches of glycogen. Since glycogen synthase can only add to chains of 4 residues, this enzyme makes those first four residues attach so that glycogen synthase can act

16

What is the only enzyme that is common to both glycogen synthesis and metabolism

Phosphoglucomutase

17

T or F, Glycogen synthesis and breakdown are reciprocally regulated, stimulation of one inhibits the other

True

18

Glycogen Phosphorylase is phosphorylated to form a, what occurs?

This is the active form of glycogen phosphorylase and triggers glycogen breakdown

19

Phosphorylase a is dephosphorylated or phosphorylated?

Phosphorylated

20

Glycogen Synthase a is dephosphorylated or phosphorylated?

Dephosphorylated

21

When glycogen synthase a is dephosphorylated, what is triggered?

Glycogen Synthesis