Lecture 17 - Glycogen Metabolism I

Question 1

Linkage of glucose within linear chain of glycogen.

Answer 1

α-1,4 glycosidic bond

Question 2

Linkage of branch points of glycogen.

Answer 2

α-1,6 glycosidic bond

Question 3

Constituents of non-reducing ends of glycogen.

Answer 3

Terminal glucose and free hydroxyl group at carbon 4

Question 4

Protien, connected to a glucose monomer at the reducing end of glycogen.

Answer 4

Glycogenin

Question 5

Protein, creates a short glycogen polymer on itself and serves as a primer for glycogen synthesis.

Answer 5

Glycogenin

Question 6

Location of glycogen degradation/extension.

Answer 6

Non-reducing ends

Question 7

Glycogen is stored within the liver/muscles/other tissues within […].

Answer 7

Granules

Question 8

Conntents of granules associated with glycogen storage.

Answer 8

Glycogen, enzymes needed for glycogen metabolism

Question 9

Defect in enzymes associated with storage granules = […]

Answer 9

Glycogen storage disorders

Question 10

Function of glycogen within the liver.

Answer 10

Regulate blood glucose levels.

Question 11

Function of glycogen within muscles.

Answer 11

Provides surplus of energy for physical activity

Question 12

Synthesis and degradation of glycogen are regulated […].

Answer 12

Independently

Question 13

First key step of glycogenesis.

Answer 13

Trapping and activation of glucose

Question 14

Enzyme of glycogenesis, forms UDP-glucose.

Answer 14

UDP-glucose pyrophosphorylase

Question 15

Second key step of glycogenesis.

Answer 15

Elongation of glycogen primer.

Question 16

Rate-limiting enzyme of glycogenesis, catalyzes transfer of glucose from UDP-glucose to non-reducing end of glycogen chain.

Answer 16

Glycogen synthase

Question 17

Glycogen synthase adds glucose forming […] bonds.

Answer 17

α-1,4 glycosidic

Question 18

Third key step of glycogenesis.

Answer 18

Branching of glycogen chains.

Question 19

Enzyme of glycogenesis, breaks of a fragment of glycogen when chain exceed 11 residues reattaching the fragment with an α-1,6 linkage.

Answer 19

Glucosyl (4:6) transferase

Question 20

Consequences of glycogen branching.

Answer 20

Increases solubility, increase # of terminal non-reducing ends, increases rate at which glycogen can be synthesized/degraded

Question 21

Glycogen degradation.

Answer 21

Glycogenolysis

Question 22

Released via glycogen breakdown.

Answer 22

Glucose-1-phosphate

Question 23

Rate-limiting step enzyme of glycogenolysis.

Answer 23

Glycogen phosphorylase

Question 24

Enzyme of glycogenolysis, rate limiting enzyme that catalyzes the cleavage of glycogen.

Answer 24

Glycogen phosphorylase (GP)

Question 25

Glycogen phosphorylase adds an […] and releases a glucose residue as glucose-1-phosphate.

Answer 25

Orthophosphate

Question 26

Co-factor, used by glycogen phosphorylase.

Answer 26

Pyridoxal phosphate (i.e. vitamin B6)

Question 27

During glycolysis, phosphorolysis of glucose residues occurs until glycogen phosphorylase gets within […] of the α-1,6 linkage of a branch point.

Answer 27

4 Residues

Question 28

Enzyme of glycolysis, converts glucose-1-phosphate to glucose-6-phosphate.

Answer 28

Phosphoglucomutase

Question 29

Enzyme of glycolysis, transfers a block of 3 of the remaining 4 glucose to the non-reducing end of the main chain forming an α-1,4 bond.

Answer 29

Transferase

Question 30

Enzyme of glycolysis, cleaves the α-1,6 bond of the single remaining glucose residue to release the free glucose.

Answer 30

α-1,6 glucosidase

Question 31

Glucose-6-phosphate is only present in the […].

Answer 31

Liver