W3-2: Glycogen metabolism Flashcards Preview

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Flashcards in W3-2: Glycogen metabolism Deck (19)
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1
Q

Linear glycogen is bonded at which glucose carbons?

A

1 (phosporylated) –> 4

2
Q

Branched glycogen is bonded at which glucose carbons?

A

1 phosphorylated –> 6

3
Q

Glc activation for glycogen synthesis

A
4
Q

Glycogen synthesis occurs in which direction?

A

1’ to 4’

5
Q

Branching enzyme name

A

glycosyl 4–>6 transferase

6
Q

About how many Glc molecules can be added at a branch point?

A

~11

7
Q

What is the benefit of having so many branch points?

A

more loose ends are available to be cleaved off the glycogen molecule

and

increases solubility (more –OH groups)

8
Q

Enzyme that cleaves Glc off glycogen

A

glycogen phosphorylase

9
Q

Two debranching enzymes

A

4:6 transferase

**moves all but one sugar**

α-1,6-glucosidase

**frees last Glc**

10
Q

Two enzymes that control glycogen synthesis/breakdown and regulation

A
11
Q

Glucagon and Epi action: fasting hepatocyte

A
12
Q

Insulin action: fed hepatocyte

A

PHOSPHORYLASE

13
Q

Epi action: fasting skeletal muscle

A

PHOSPHORYLASE

14
Q

Insulin action: fed skeletal muscle

A
15
Q

GSD 0

A

Glycogen synthase deficiency

16
Q

GSD I (van Gierke disease)

A

Glucose-6-phosphatase deficiency

(cannot remove Glc from liver)

17
Q

GSD III (Cori disease)

A

1,6-glucosidase activity deficincy

(cannot remove single sugar)

18
Q

GSD IV

A

4:6-transferase defiency

fatal

19
Q

GSD V (McArdle disease)

A

Muscle glycogen phosphorylase deficiency

–>exercise intolerance