Quiz 3 Glycogen Synthesis (Glycogenesis)

Question 1

What acts faster when glucose is needed, Glycogenolysis or GNG?

Answer 1

Glycogenolysis

Question 2

Two primary storage sites of glycogen?

Answer 2

Liver and skeletal muscle

Question 3

For review…a branch occurs how many glucose apart? What type of bond?

Answer 3

10 glucose molecules…A(1-6) bond

Question 4

Muscle or liver lack enzyme to release glucose? What enzyme?

Answer 4

Muscle, glucose-6-phosphatase

Question 5

Glycogenesis is initiated by?

Answer 5

Glucose-6-phosphate

Question 6

If no glycogen fragment available, what begins the glycogen chain?

Answer 6

Glycogenin

Question 7

Enzyme which starts the glycogen chain with amino acid tyrosine

Answer 7

Glycogen initiator synthase

Question 8

How many ATP used to make glucose-6-phosphate?

Answer 8

1

Question 9

Reactants of Phosphoglucomutase?

Answer 9

Glucose-6-phosphate

Question 10

Products of Phosphoglucomutase?

Answer 10

Glucose-1-phosphate

Question 11

What breaks apart pyrophosphate when making UDP-glucose?

Answer 11

Pyrophosphatase

Question 12

What high energy compound is used to make UDP-Glucose?

Answer 12

UTP (uridine triphosphate)

Question 13

What are the reactants of UDP-glucose Pyrophosphorylase?

Answer 13

UTP + Glucose-1-phosphate

Question 14

What are the products of UDP-glucose Pyrophosphorylase?

Answer 14

PPi + UDP-Glucose

Question 15

How many high energy molecules are used to synethsize glycogen?

Answer 15

3

Question 16

What occurs during chain elongation? Where is this taking place in the cell?

Answer 16

Glucose is being added to chain, occurs in the CYTOSOL.

Question 17

What enzyme is involved with Chain elongation? What types of bonds are being made?

Answer 17

Glycogen synthase, alpha (1-4) bonds

Question 18

After ~ how many glucose added to the chain do we need to begin to branch?

Answer 18

7 (do not confuse this with the question earlier about how many glucose are in row until we find a branch which is 10)

Question 19

Which enzyme is involved with branching and alpha (1-6) bonds?

Answer 19

Glycosyl-(4:6)-transferase

Question 20

What is the key enzyme responsible for synthesis of glycogen?

Answer 20

Glycogen synthase

Question 21

Allosteric regulation of glycogen synthase would be activated by?

Answer 21

glucose-6-phosphate

Question 22

During exercise, is glycogenolysis or glycogenesis being active?

Answer 22

During exercise glycogenolysis (breakdown), and post exercise glycogenesis (synthesis)

Question 23

If you phosphorylate glycogen synthase (hormonal regulation), will be it be active or inactive?

Answer 23

Inactive

Question 24

Give examples of things that will inactivate glycogen synthase?

Answer 24

Glucagon, Epinephrine, norepinephrine

Question 25

What will de-phosphorylate and active the enzyme?

Answer 25

Insulin

Question 26

In other words, Glucagon would inhibit what and stimulate what?

Answer 26

Inhibit glycogen synthesis and stimulate glycogen breakdown

Question 27

High ATP, High levels of glucose, Insulin, and low glycogen levels do what to glycogen synthase?

Answer 27

Stimulate

Question 28

Primary site of fructose disposal?

Answer 28

liver

Question 29

What are the two enzymes essential for fructose metabolism highly expressed in the liver?

Answer 29

Fructokinase, and Triokinase

Question 30

Low-dose fructose causes what?

Answer 30

A threefold increase in net liver glycogen synthesis

Question 31

Does fructose benefit muscle glycogen synthesis?

Answer 31

NOPE only live glycogen synthesis.

Question 32

After intense exercise, glycogen synthesis happens at initially a high rate, it rapidly declines to about a 1/5th by 60 minutes and a 1/9th by 120 minutes. What are the two reasons for this?

Answer 32

Increased glucose uptake (GLUT 4) and increased enzyme activity (glycogen synthase)

Question 33

What phase of glycogen synthesis is 30-60 mins after exercise and is insulin independent?

Answer 33

Rapid phase

Question 34

After rapid phase, insulin dependent, and has a much slower rate of glycogen synthesis?

Answer 34

Slow phase

Question 35

True or false, by increasing carb consumption, does it increase the rate of glycogen storage by more than 150%?

Answer 35

True

Question 36

Incorporating ingestion of what along with moderate intake of carbs leads to higher muscle glycogen synthesis rates?

Answer 36

Proteins/amino acids

Question 37

When enzymes of glycogen degradation or glycogen synthesis are defective and leads to increased storage but impaired breakdown?

Answer 37

Glycogen storage disease (GSD)

Question 38

Most common GSD, is genetic, glucose – phosphatase deficiency (hypoglycemia)?

Answer 38

GSD type 1 or Von Gierk’s disease