E2 Glycogenolysis (1/2 Bobby)

Question 1

What are the 2 primary storage sites of glycogen?

Answer 1

1. Liver

2. Skeletal muscle

Question 2

What type of glycosidic bond forms chains? Branch?

Answer 2

Alpha (1-4)

Alpha (1-6)

Question 3

Where is glycogen stored in the cell?

Answer 3

Cytosol

Question 4

What supplies glucose to the brain?

Answer 4

Liver (glucose to brain b/w meals)

Question 5

What is the purpose of glycogenolysis in
A. Muscle
B. Liver

Answer 5

A. Energy

B. Blood glucose homeostasis

Question 6

T/F. Gluconeogenesis is faster than glycogenolysis.

Answer 6

False

Question 7

What enzyme does glycogen phosphorylase require?

Answer 7

Pyridoxal phosphate (B6)

Question 8

What type of bond does glycogen phosphorylase break?

Answer 8

Alpha (1-4)

Question 9

What is the product of glycogen phosphorylase?

Answer 9

G-1-P

Question 10

What enzyme facilitates G-1-P —> G-6-P?

Answer 10

Phosphoglucomutase

Question 11

What is the fate of G-6-P in muscle?

Answer 11

Glycolysis

Question 12

What enzyme facilitates G-6-P —> free glucose in the liver?

Answer 12

G-6-phosphatase

Question 13

G-6-P can be ________ in the pentose phosphate pathway.

Answer 13

Oxidized

Question 14

What is the key regulatory enzyme of glycogenolysis?

Answer 14

Glycogen phosphorylase

Question 15

What is the fate of free glucose in the liver?

Answer 15

Sent to the cytosol and then to the blood

Question 16

When will glycogen phosphorylase cease breaking alpha (1-4) bonds?

Answer 16

When it is 4 glucose residues away from branch point

Question 17

Which enzyme removed outer 3 glucose molecules? (aka make longer chain)

Answer 17

Glucosyl (4:4) transferase

Question 18

Which enzyme removes the last glucose of a branch?

Answer 18

Amylo-alpha (1,6)- glucosidase

Question 19

After alpha (1-6) bond is broken in the muscle, it is phosphorylated via ________.

Answer 19

Hexokinase

Question 20

MATCHING
A. Muscle B. Liver C. Glycogen phosphorylase B
D. Glycogen phosphorylase A E. R-state F. T-state

1. Active form
2. Inactive form

Answer 20

A. 2
B. 1
C. 2
D. 1
E. 1
F. 2

Question 21

Will glucose binds to phosphorylase A in liver or muscle?
What happens to the state (R/T)?
Will it inhibit or stimulate glycogenolysis?

Answer 21

Liver
R state –> T state
Inhibit

Question 22

T/F. Liver energy change impacts glycogenolysis.

Answer 22

False

Question 23

T/F. Muscle energy change impacts glycogenolysis.

Answer 23

True

Question 24

High [AMP] binds to phosphorylase B in liver or muscle?
What happens to the state (R/T)?
Will is inhibit or stimulate glycogenolysis?

Answer 24

Muscle
T state –> R state
Stimulate

Question 25

High [ATP] binds to phosphorylase B. Will it inhibit or stimulate glycogenolysis?

Answer 25

Inhibit

Question 26

High [G-6-P] binds to phosphorylase B. Will is inhibit or stimulate glycogenolysis?

Answer 26

Inhibit

Question 27

T/F. Glycogen phosphorylase B reminds inactive until stimulated.

Answer 27

True

Question 28

Type of competition between G-6-P and ATP in skeletal muscle?

Answer 28

Allosteric

Question 29

What two hormones will stimulate the CAMP cascade?

Answer 29

Epinephrine and Glucagon

Question 30

When will epinephrine be released in response to?

Answer 30

Fear and Exercise

Question 31

What tissue will you primarily find epinephrine?

Answer 31

Muscle

Question 32

When will glucagon be released in response to?

Answer 32

Low blood sugar

Question 33

What tissue will you find glucagon?

Answer 33

Liver

Question 34

T/F. Epinephrine and Glucagon both stimulate the CAMP cascade, which will eventually phosphorylate the enzyme, converting it from glycogen phosphorylase a ---> b.

Answer 34

False; glycogen phosphorylase b ---> a

Question 35

In covalent modification regulation using the CAMP cascade, what enzyme must be phosphorylated and activated?

Answer 35

Glycogen phosphorylase kinase

Question 36

Once glycogen phosphorylase kinase is activated, what enzyme will activated? What happens to phosphorylase B/A?

Answer 36

Glycogen phosphorylase | phosphorylase b --> phosphorylase a

Question 37

What enzyme is a second messenger for the CAMP cascade?

Answer 37

Adenylyl cyclase

Question 38

What is the subunit for glycogen phosphorylase kinase?

Answer 38

Calmodulin

Question 39

T/F. When calcium binds to calmodulin forming the Ca2+-calmodulin complex, glycogen phosphorylase kinase will be inhibited, therefore activating glycogen breakdown.

Answer 39

False; activate glycogen phosphorylase kinase

Question 40

In the muscle, what will trigger the release of Ca2+ from the sarcoplasmic reticulum?

Answer 40

Muscle contraction

Question 41

In the liver, what will trigger the release of Ca2+?

Answer 41

"Fight or Flight" response

Question 42

Once energy or glucose needs have been satisfied (glucagon and epinephrine no longer present), CAMP is converted to _________ and no longer activates _________.

Answer 42

Converted to AMP | No longer activated PKA

Question 43

What enzyme removes the phosphate group from glycogen phosphorylase converting it back to an inactive form?

Answer 43

Protein phosphatase1 (PP1)

Question 44

What is the storage location of glycogen in the brain?

Answer 44

Astrocytes (adults) and Embryonic neurons

Question 45

T/F. The highest concentration of glycogen in the brain is where there is the least amount of synaptic activity.

Answer 45

False

Question 46

_____ matter has 2x's the amount of glycogen concentration than _____ matter.

Answer 46

Gray, White

Question 47

T/F. Glycogen metabolism regulation in the brain is similar to that in the liver and skeletal muscle via allosteric regulation, Ca2+, AMP, and epinephrine/norepinephrine.

Answer 47

True

Question 48

What four factors will stimulate glycogenolysis?

Answer 48

1. low energy 2. epinephrine/norepinephrine 3. Glucagon (low glucose) 4. Calcium (m. contraction or stress)

Question 49

T/F. The same environment as glycogenolysis will stimulate glycogenesis.

Answer 49

False; opposite environment