Glycogen Metabolism Flashcards

1
Q

What enzyme links glucose molecules together?

A

glycogen synthase

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2
Q

Whihc enzyme lyses glycogen and converts it to G-1-P?

A

glycogen phosphorylase

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3
Q

The which enzyme releases a free glucose?

A

debranching enzyme (alpha-1,6- glucosidase)

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4
Q

Glycogenin is attached to which end of the glycogen chain?

A

Reducing end

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5
Q

Which end are glucose molecules added to?

A

Nonreducing end

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6
Q

What enzyme transfers the 4 glucoses on the branched chain onto the core chain of glycogen?

A

4:4 transferase

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7
Q

The last unit on the branch is hydrolyzed by which enzyme thereby releasing free glucose?

A

alpha-1,6-glucosidase

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8
Q

In the liver, what is the fate of the G-1-P units?

A

Converted to free glucose to maintain blood glucose levels

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9
Q

In the muscle, what is the fate of the G-6-P units?

A

Used in glycolysis to produce ATP for contraction

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10
Q

What tissue does Ca-calmodulin work in?

A

Muscle

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11
Q

What does Ca-calmodulin activate?

A

Phosphorylase kinase which stimulates glycogenolysis

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12
Q

What enzyme is the key regulatory enzyme in glycogenolysis?

A

glycogen phosphorylase

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13
Q

What is the rate limity enzyme in glycogen synthesis?

A

Glycogen synthase

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14
Q

What does protein kinase A do to glycogen synthase?

A

Turns it off—-> decreases glycogen synthesis

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15
Q

What does protein kinase A do to glycogen phosphorylase?

A

Turns it on—-> increases lysis

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16
Q

What does glucagon(liver) and epinephrine (liver + muscle) do?

A

Stimulate glycogenolysis

17
Q

What does insulin (liver + muscle) do?

A

Stimulate glycogen synthesis

18
Q

In fed state why does glycogen degradation decrease?

A

Glucagon is low so cAMP cascade isn’t activated

19
Q

After a meal why isn’t glycogen degradation stimulated in the muscles?

A

Low levels of cAMP, AMP, Ca, and epinephrine

20
Q

What enzyme in lysosomes degrade glycogen into glucose?

A

alpha-glucosidase

21
Q

What enzyme converts G-6-P to glucose?

A

Glucose-6-phosphatase