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Flashcards in Sugar Metabolism Deck (35):
1

Describe prepatory phase of glycolysis

Phosphorylation of glucose and its conversion to glyceraldehyde 3 phosphate

2

Payoff phase of glycolysis

Oxidative conversion of glyceraldehyde 3 phosphate to pyruvate and coupled formation of ATP to NADH

3

What are fates of pyruvate?

TCA cycle, LDH, fermentation, biosynthesis

4

What are high energy enzymes used in gluconeogenesis to bypass pyruvate kinase?

Pyruvate carboxylase and PEP carboxykinase

5

What is the cofactor uses in pyruvate carboxylase?

Biotin

6

What does biotin do?

Adds Carboxyl group to pyruvate to make oxaloacetate

7

What two molecules signal low energy?

AMP and ADP

8

At high amounts of AMP what tissue favors glycolysis?

Muscle tissue

9

At low AMP what tissue does not favor glycolysis?

Liver

10

Which molecule is the transfer for reducing equivalents?

Malate

11

What are the four bypass enzymes of gluconeogenesis?

Pyruvate carboxylase, PEP carboxykinase, F16BP, glucose 6 phosphotase

12

What molecule inhibits F16BP?

AMP

13

What converts oxaloacetate to PEP?

PEP carboxykinase

14

If lactate is starting source for gluconeogenesis, is malate needed?

No it creates its own reducing equivalents in the cytosol and uses a isozyme of PEP carboxykinase in the mitochondria

15

What is the net result of the pentode phosphate pathway?

2 NADPH, ribose 5 phosphate, co2 and two protons

16

What inhibits PFK 1?

ATP, citrate

17

What allosterically activates PFK1?

Fructose 26 Bisphosphate and amp

18

Insulin leads to what kind of cascade?

Dephosphorylation

19

Glucagon leads to what kind of cascade?

Phosphorylation

20

What is the substrate for PFK2/FBPase2

Fructose 6 phosphate

21

Xylulose 5 phosphate activates what metabolic pathway by stimulating which enzyme?

Glycolysis and PFK2/FBPase2

22

In liver if glucagon goes up, what happens to pyruvate kinase?

It is phosphorylated and inhibited

23

What inhibits Pyruvate Kinase?

ATP, Acetyl-CoA, long chain Fatty acids, alanine

24

What is a phosphorylase?

Enzyme using inorganic phosphate to break a bond

25

Glycogen phosphorylase makes what molecule?

Glucose 1 phosphate

26

What hormone activates glycogen breakdown?

Epinephrine

27

What are benefits to glycogen phosphorolysis?

Glucose 6 phosphate is made without ATP, 1 ATP is used in predatory phase of glycolysis, there is a net gain of 3 ATP for glycolysis

28

What does phosphoglucomutase do?

Catalyzes glucose 1 phosphate to glucose 6 phosphate

29

What is the difference in glycogen breakdown in liver and muscle?

In liver glycogen will put glucose in blood. In muscle it is used for glycolysis

30

In the liver what enzyme is needed for glucose to leave the cell?

Glucose 6 phosphotase

31

Which tissue has two forms of glycogen phosphorylase?

Muscle. Phosphorylase a is active. Phosphorylase b not as active

32

cAMP activates which enzyme to stimulate glycogen breakdown in muscle?

PKA. Stimulates glycogen breakdown

33

cAMPincreases in response to what hormones?

Epinephrine and glucagon

34

When is glycogen synthase active?

When it is dephosphorylated

35

When is glycogen synthase inactive?

When it is phosphorylated by GSK3