Glycogen Metabolism Flashcards

1
Q

What is the fastest form of stored energy?

A

Glycogen

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2
Q

Where does Glycogen synthesis occur?

A

Liver

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3
Q

90% of glycogen is stored where?

A

muscle

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4
Q

What is a branched-chain homopolysaccharide made from alpha-d-glucose?

A

Glycogen

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5
Q

What is the primary bond type in glycogen?

A

alpha 1-4 glycosidic bond

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6
Q

what type of bond forms a glycogen branch?

A

alpha 1-6 glycosidic bond

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7
Q

Which types of enzymes break down glycogen chains?

A

Lysosomal Enzymes

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8
Q

how much does 4 kcals equal to grams of glycogen?

A

1g=4kcals

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9
Q

Which organ is saturated with glycogen during fed states and depleted during fasting states?

A

Liver glycogen

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10
Q

Which glycogen storage is NOT depleted during short fasting states, but may be depleted during long term fasting states?

A

Muscle

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11
Q

When is muscle glycogen depleted in the muscles?

A

strenuous excersise

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12
Q

Which monosaccharide doesn’t use hexokinase?

A

Glactose -> Glucose

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13
Q

What are the 3 enzymes used in glycogen synthesis?

A

Phosphoglucose Mutase
UDP Glucose Phosphorylase
Glycogen Synthase

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14
Q

Glycogen Synthesis 5 steps

A

-Glucose 6 Phosphate

  >Phosphoglucomutase 

-Glucose 1 Phosphate

  >UDP-Glucose Phosphorylase 

-UDP Glucose

  >Glycogen synthase

-UDP

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15
Q

Which diseases has a glucose-6-phosphatase defect?

Type I

A

Type I- Von-Gierke Disease

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16
Q

Which organ(s) does Von Gierke Disease affect?

A

liver and kidney

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17
Q

Which disease is an alpha-1,4-glycosidase defect?

Type II

A

Type II-Pompe disease

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18
Q

Which organ(s) does Pompe disease affect?

A

All organs

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19
Q

Which disease is an amylo- 1,6- glycosidase defect?

Type III

A

Type III-Cori Disease

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20
Q

Which organ(s) does Cori Disease affect?

A

Muscle and liver

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21
Q

How many grams of glycogen are in your muscle?

A

400g (90%)

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22
Q

How may grams of glycogen are in your liver?

A

100g (10%)

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23
Q

Which disease has a Branching enzyme (glycosyl-4,6-transferase) defect?
(Type IV)

A

Type IV- Andersen Disease

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24
Q

Which organs does Andersen Disease effect?

A

Liver and Spleen

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25
Q

Which disease has a phosphorylase defect?

Type V

A

Type V- McArdle disease

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26
Q

Which organ(s) McArdile disease effect?

A

Muscles

27
Q

What does Glycogen synthase catalyze?

A

alpha (1-4) linkage formation toyield alpha-amylose

28
Q

What is the branching enzyme that forms glycogen?

A

Amylo-(1,4-1,6)-transglycosylase

aka. 4,6-glycosyl transferase

29
Q

How far apart do branches need to be?

A

4 glycosyl residues apart

30
Q

When creating a glycogen from scratch, what needs to be available to start a chain?

A

Glycogenin + Tyrosine

31
Q

Which high energy molecule do you use to stabilize the high energy carbon during glycogen synthesis?
What do you need to bring this in and what is the product?

A

UDP

PPi

32
Q

Which enzyme is used to remove glycosyl units off a glycogen chain?
What does this process form from the cleaved residue?

A

Phosphorylase converts a glycosyl unit to G1P

33
Q

Which enzyme converts between G1P and G6P?

A

Phosphoglucomutase

34
Q

What is the debranching enzyme that cleaves the a(1-4) glycosidic bonds?

A

glycogen phosphorylase

35
Q

what is a limit dextrin?

A

the last 4 glycosyl units on a branch

36
Q

Where can Glucose 6 Phosphate be converted back into Glucose?

A

only in the liver

37
Q

which enzyme converts glucose 6 phosphate back into glucose?

A

glucose 6 phosphatase

38
Q

Which enzyme is the cleaving enzyme?

A

glycosidase

39
Q

Why is G6P converted back into Glucose?

A

So the liver can send it through the blood for other tissues

40
Q

Which state does gluconeogenesis occur in?

A

fasting state

41
Q

Which state does glycogen synthesis occur in?

A

Well fed state

42
Q

What is the purpose of gluconeogenesis?

A

Creating new glucose

43
Q

Which organs need a continuous supply of glucose?

A

Brain, RBCs, eyes, testes, and exercising muscles

44
Q

How long can liver glycogen supply the body?

A

10-18 hrs

45
Q

In prolonged states of fasting, what else can form glucose?

4

A

Amino Acids
Lactate
Glycerol
a-ketoacids

46
Q

What are the 2 enzymes in the malate-asparate shuttle?

A
malate dehydrogenase (oxylacetate to malate)
asparate aminotransferase (asparate to oxylacetate)
47
Q

What is the process of reversing the pyruvate rate limiting step?

A

-Pyruvate

 >pyruvate carboxylase

-Oxylacetate

  >PEPCK 

-Phosphoenyl Pyruvate

48
Q

What are the three rate limiting enzymes of glycolysis?

A

Kinase
Phosphofructose Kinase
Pyruvate Kinase

49
Q

Which enzymes reverse the glycolysis rate limiting steps?

A
  • Pyruvate carboxylase + PEPCK
  • Fructose Bisphosphatase
  • Glucose 6 Phosphatase
50
Q

Which enzyme converts pyruvate or oxylacetate? What are the products and substrates?

A

Pyruvate carboxylase

ADP + Pi

51
Q

Which enzyme converts oxylacetate to phosphoenylpyruvate? What are the products and substrates?

A

PEPCK
(phosphoenylpyruvate carboxykinase)

GDP + CO2

52
Q

Which enzyme converts Fructose-1,6-Bisphosphate to Fructose-6-Phosphate? What are the products and substrates?

A

Fructose 1,6-Bisphosphatase

—>Pi

53
Q

Which enzyme converts Glucose-6-Phosphate to Glucose? What are the products and substrates?

A

Glucose 6 Phosphatase

—>Pi

54
Q

What kind of hormone is glucagon?

A

Pancreatic islet hormone

55
Q

What is Dehydrogenase one job?

A

Oxidative Phosphorylation

oxidative-reduction reaction

56
Q

What does glucagon activate when it connects to the phospholipid bilayer during a starvation state?

A

G-protein series

57
Q

What is adenylate cyclase’s one job after it is activated?

A

take ATP and turn it into cAMP

58
Q

What is the 1st messenger and 2nd messenger?

A

1) Glucagon

2) cAMP

59
Q

What is the one job of cAMP?

A

activate protein kinase A

60
Q

What is Protein Kinase A’s one job?

A

Phosphorylation (add phosphate group)

61
Q

When is the second messenger system inactive?

A

fasting state-Gluconeogenesis

62
Q

When are we phosphorilating PFK2?

Is is active or inactive?

A

During Gluconeogenesis/Fasting State

Inactive

63
Q

What happens when PFK2 is phosphorylated?

A

PFK2 becomes inactivated which then activates Fructose Bisphosphatase