Glycogen metabolism Flashcards

1
Q

glucose is linked by _____ and ______ linkages to form glycogen

A

alpha 1,4 and 1,6

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2
Q

glycogen is stored in ___ and ____

A

liver; muscle

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3
Q

G1P–>UDPGluc is catalyzed by

A

UDP-gluc Pyrophosphorylase

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4
Q

The name of the key regulatory enzyme in glycogen synth

A

glycogen synthase

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5
Q

glucoses are added to the _____ end of the glycogen, one glucose at a time, forming ____ linkage (through glycogen synthase)

A

non reducing; alpha 1,4

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6
Q

what is the difference between synthethase and synthase?

A

the latter does not need ATP for energy

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7
Q

how is 1,6 linkage formed?

A

thru UDP glucose and glycogen synthase, then branching enzyme that transfers 6-7 glucose residues to another glucose

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8
Q

To start a new glycogen molecule, need to start with ___ , that adds on the first 8 glucose residues to itself on Tyr ___

A

glycogenin; 194

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9
Q

_____ degrades glycogen from nonreducing ends of the molecule into ____

A

glycogen phosphorylase; glucose 1-P

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10
Q

Gluc1P is converted to ____ by _____

A

Gluc6P by phosphoglucomutase

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11
Q

G6P forms _____ in the ___

A

free glucose; liver

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12
Q

in muscle, G6P enters the ____ path to produce energy

A

glycolytic

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13
Q

glycogen phosphorylase “a” is the ___ form while “b” is the ___ form; the only diff is the presence of ___ on the GPa serine residue

A

active; inactive; phosphate

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14
Q

the activator of GP in muscle is __, inhibitors are __ and ___

A

AMP; ATP, G6P

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15
Q

what is the inhibitor of liver GP?

A

glucose

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16
Q

what is the difference between GSa and GSb?

A

a is active and unphosphorylated, b is inactive and phosphorylated

17
Q

In both muscle and liver, glycogen synthase b is activated by _____

A

G6P

18
Q

GSa–>GSb mostly by this type of protein kinase:

A

GSK-3

19
Q

GSb–>GSa mostly by this type of protein phosphatase

A

PP1

20
Q

these hormones signal need for glycogen breakdown; this hormone signals the opposite

A

epinephrine (muscle) and glucagon (liver); insulin

21
Q

phosphorylase kinase is activated by ____

A

calcium

22
Q

cyclic AMP activates ______, which activates ______, which activates ____ for the breakdown of glycogen

A

protein kinase a; phosphorylase kinase, phosphorylase a

23
Q

insulin binding phosphorylates ____, rendering it ___ , meaning glycogen synthase will remain activated. Insulin also activates ____

A

GSK3; inactive; PP1

24
Q

Insulin increases the number of this type of glucose transporters

A

GLUT4