Lecture 27 - Glycogen Met. II

Question 1

End product of glycogenolysis

Answer 1

Glucose-1-P

Question 2

Enzymes of glycogenolysis

Answer 2

1) Glycogenphosphorylase (GP)
2) Glycogen debranching enzyme (cleaves a-1,6)
3) Phosphoglucomutase (moves 3 sugars)

Question 3

Branch point of glycogen is what kind of bond?

Answer 3

a-1,6

Question 4

Lengths of glycogen bound by what type of bond?

Answer 4

a-1,4

Question 5

Cleaves glycogen to form a G-1-P

Answer 5

Glycogenphosphorylase

Question 6

Removes 3 glucose molecules near the a-1,6 branch point and places them on non-reducing end of another chain

Answer 6

transferase

Question 7

Co-factor used in glycogenphosphatase

Answer 7

Vitamin B6

Question 8

Cleaves the a-1,6 bond and removes the G-1-P by that bond

Answer 8

a-1,6 debranching enzyme (AKA “a-1,6 glucosidase”)

Question 9

Moves the glucose released by the a-1,6 debranching enzyme to another free end of glycogen.

Answer 9

transferase

Question 10

Location of glucose-6-phosphatase

Answer 10

liver endoplasmic reticulum

Question 11

Phosphoglucomutase

Answer 11

Converts G-1-P to G-6-P

Question 12

Mutation to G-6-Pase in liver/kidney. Results in severe hypoglycemia, as glucose is not cleaved from glycogen.
A. GSD II Pompe
B. GSD V McArdle
C. GSD IV Hers
D. GSD I Von Gierke

Answer 12

D. GSD I Von Gierke

Question 13

Mutation to muscle phosphorylase. Prevents the release of glucose from glycogen during heavy exercise, resulting in decreased muscle contraction.
A. GSD II Pompe
B. GSD V McArdle
C. GSD IV Hers
D. GSD I Von Gierke

Answer 13

B. GSD V McArdle

Question 14

Mutation of liver phosphorylase. Causes severe hypoglycemia. Like Type I GSD, but mild.
A. GSD II Pompe
B. GSD V McArdle
C. GSD IV Hers
D. GSD I Von Gierke

Answer 14

C. GSD IV Hers

Question 15

Mutation to alpha-1,4-glucosidase. Inability to cleave glycogen, causing severe hypoglycemia and increased glycogen stores. Usually fatal before 2 years of age.
A. GSD II Pompe
B. GSD V McArdle
C. GSD IV Hers
D. GSD I Von Gierke

Answer 15

A. GSD II Pompe

Question 16

Deactivation of GS in the face of high glucose levels is accomplished via _____.

A. PFK
B. PKA
C. GSK
D. PP1

Answer 16

C. GSK (Addition of Pi to GS deactivates the enzyme, and stops glycogen synthesis)