BSI Lecture 34 Glycogen Metabolism/Gluconeogenesis

Question 1

______ is the storage form of glucose.

Answer 1

Glycogen

Question 2

T or F? Glycogen is a monosaccharide.

Answer 2

False, it’s a polysaccharide

Question 3

Where is glycogen primarily stored?

Answer 3

Liver and muscle cells

Question 4

Stores are limited; once stores are maximized, no more glucose can be stored as glycogen. Which process is this in?

Answer 4

Glycogenesis

Question 5

T or F? Glycogenesis only occurs in the liver.

Answer 5

False, it occurs in both the liver and the muscle cells

Question 6

What is the rate-limiting enzyme for Glycogenesis?

Answer 6

Glycogen synthase

Question 7

What is the purpose of Glycogenesis?

Answer 7

To store glycogen in the liver and muscle

Question 8

In _____, glucose is added to the glycogen tree.

Answer 8

Glycogenesis

Question 9

Glucose-1-phosphate → uridine diphosphate glucose. What enzyme does this?

Answer 9

Glycogen synthase

Question 10

What is the purpose of glycogenolysis?

Answer 10

To break down glycogen stores.

Question 11

What happens to glucose-6-phosphate when there is enough energy in the cell?

Answer 11

It will be converted to glucose-1-phosphate then to uridine diphosphate glucose then it is added to glycogen tree.

Question 12

What enzyme does this? Glycogen → glucose-1-phosphate

Answer 12

Glycogen phosphorylase (cleaves glucose from the glycogen tree)

Question 13

Glycogenolysis: Glucose-1-phosphate → glucose-6-phosphate. What happens in skeletal muscle?

Answer 13

There no phosphatase enzyme so glucose-6-phosphate cannot leave the cell; therefore, glucose-6-phosphate enters glycolytic pathway.

Question 14

T or F? The muscle cell breaks down glycogen to use for itself.

Answer 14

True

Question 15

Glycogenolysis: Glucose-1-phosphate → glucose-6-phosphate. What happens in the liver?

Answer 15

Glucose-6-phosphate → glucose (glucose-6-phosphatase)

The glucose is released into the blood for use by other tissues (primarily the brain).

Question 16

T or F? The liver breaks down glycogen to use for itself.

Answer 16

False

Question 17

Glucose is formed from non-carbohydrate sources in which process?

Answer 17

Gluconeogenesis

Question 18

Glucose is formed from non-carbohydrate sources, what are they?

Answer 18

1. Certain Amino Acids
2. Lactate
3. Glycerol
4. Krebs Cycle intermediates

Question 19

T or F? Gluconeogenesis occurs in the liver and muscles.

Answer 19

False, liver and kidneys

Question 20

Lactate and certain amino acids can be converted into _____, which is then converted into glucose via “reverse” glycolysis.

Answer 20

Pyruvate

Question 21

_______ can be converted into glyceraldehydes-3-phosphate, which then can be converted into glucose via “reverse” glycolysis.

Answer 21

Glycerol

Question 22

What enzyme regulates glycogenolysis?

Answer 22

Glycogen phosphorylase

Question 23

T or F? (+) AMP, glucagon (stimulates glycogenolysis in the liver, but not in muscle), epinephrine. This regulates glycogenolysis.

Answer 23

True

Question 24

(-) ATP, insulin regulates which process?

Answer 24

Glycogenolysis

Question 25

What regulates glycogenesis?

Answer 25

1. Rate limiting enzyme:
   a. Glycogen synthase
2. (+) insulin
3. (-) glucagon, epinephrine

Question 26

(+)Glucagon and (-)insulin are regulators of ________

Answer 26

Gluconeogenesis

Question 27

T or F? Insulin is required for the brain to take up glucose and use it for energy

Answer 27

False, it is not required

Question 28

________ does not inhibit glycolysis in the brain

Answer 28

Glucagon

Question 29

in times of high concentration of glucagon and low concentration of insulin (such as during a state of starvation), the brain is able to take up and utilize the glucose that is being dumped out into the blood by the liver via ________ and ________.

Answer 29

Gluconeogenesis; glycogenolysis

Question 30

What is the rate-limiting enzyme for Glycogenesis?

Answer 30

Glycogen synthase

Question 31

Why is it important for the liver to “dump” glucose into the bloodstream?

Answer 31

It is for the brain to use because it is primarily what the brain use for energy.

Question 32

One of the roles of the liver is to _____ blood ________ levels for the brain.

Answer 32

maintain; glucose

Question 33

What happens to insulin and glucagon levels at 4 am?

Answer 33

Insulin drops and glucagon rises

Question 34

What is taking place in the body to maintain the blood/glucose level?

Answer 34

Glycogenolysis maintains blood/sugar

Glyconeogenesis maintains stores

Question 35

What does glucagon do to glycolysis?

Answer 35

Inhibits

Question 36

What tissue is Glucose-6-phosphatase expressed in?

Answer 36

Liver

Question 37

“Reverse glycolysis” is _______________

Answer 37

Gluconeogenesis

Question 38

_______ is a Krebs Cycle intermediate that can be used for Gluconeogenesis.

Answer 38

Oxaloacetate (OAA)

Question 39

What two parts of the body can use Gluconeogenesis?

Answer 39

Liver and kidneys

Question 40

In times of starvation, the liver will produce glucose for the _______ and _____ _______ _____.

Answer 40

Brain; red blood cells

Question 41

Low energy status would ______ glycogenolysis while high energy status would ______ it.

Answer 41

Stimulate; inhibit

Question 42

Glycogenolysis: In general, Glucagon will stimulate _____ pathways.

Answer 42

Catabolic

Question 43

Glycogenolysis: Insulin will stimulate ______ pathways.

Answer 43

Anabolic

Question 44

T or F? Glycogenesis is an anabolic type reaction.

Answer 44

True

Question 45

T or F? Glucagon works in muscle tissue only.

Answer 45

False, liver