[2] Class 7: Glycolysis And Gluconeogenesis Flashcards Preview

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Flashcards in [2] Class 7: Glycolysis And Gluconeogenesis Deck (88)
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31

Strategy to stage 1 glycolysis:

Traps the glucose in cell, for a A compound that can be readily cleaved into 2 phosphorylated 3- carbon units

32

What enzyme does liver use to convert glucose into glu-6-P?

Glucokinase

33

What are the 2 steps involving energy investment in stage 1 glycolysis?

Glucose->G6P by hexokinase/glucokinase

F6P-> F1,6BP by phosphofructokinase

34

What regulates hexokinase?

Negative feedback inhibition by product- G6P

35

Regulation of glucokinase:

Stimulated by glucose, F-1P, and insulin

Inhibited by glucagon and F6P

36

Regulation of phosphofructokinase

Stimulated by AMP and F2,6-BP

Inhibited by ATP and Citrate

37

Which stage of glycolysis?

Fructose 1,6-BP into 2 3-C fragments by Aldolase reaction
(And isomerase)
Products are readily interconvertible

Stage 2

38

What conditions represent high energy? (3)

High ATP

High NAD+

Low NADH

39

When there's high energy which of the products of stage 2, DHAP and GAP (G3P) is favored?

DHAP is favored under high energy conditions b/c it is converted to glycerol 3 phosphate- that way it can form triacylglycerols -FAT

40

What percentage of f1,6BP becomes GAP, usually?

Usually, 99% becomes GAP to continue glycolysis....in the event of high energy conditions the reaction will regress to DHAP for fat storage

41

Glyceraldehyde 3-P creates:

NADH (x2) that will be used in oxidative phosphorylation

42

1,3-BPG is converted to 3-PG by

Phosphoglycertae kinase and this forms the first ATP (x2) of glycolysis

43

2-PG is converted to_______ by:

Phosphoenolpyruvate by dehydration rxn by enolase

44

Phosphate is removed from phosphoenolpyruvate by:_________ creating:

Pyruvate kinase;

Pyruvate (x2)

45

Pyruvate is what type of molecular structure?

Stable ketone

46

3 irreversible steps of glycolysis:

1- glu-G6P

3-F6P-F1,6BP

10-PEP- Pyruvate

47

Regulation of pyruvate kinase:

Stimulated by insulin and Fructose 1,6-BP

Inhibited by Alanine, ATP, and glucagon

48

After glycolysis, aerobic:

Anaerobic?

Pyruvate to TCA;

Pyruvate to lactate--then, hopefully cori cycle...

49

Disaccharide of glucose and fructose makes=

Sucrose

50

Disaccharide composed of glucose and galactose =

Lactose

51

Fructose and galactose are converted to:

Glycolysis intermediates

52

In times of high energy, fructose quickly turns to:

FAT

53

Why would fructose quickly turn to fat in times of high energy?

Remember that GAP is readily interconvertible w/ DHAP, and although GAP is formed 99% of the time...this isn't the truth when there is high energy conditions b/c the GAP is converted to DHAP which becomes triacylglycerols- it is the backbone of fat.

54

3 regulated steps in glycolysis for ATP need

Hexokinase

PFK

Pyruvate kinase

55

Main organ in glucose regulation

Liver

56

NO hexokinase in liver: it is glucokinase....how is this regulated?

Glucose is permanently trapped in liver cell.

It is not inhibited by G3P (product of glucokinase)

57

What type of regulation is used for pyruvate kinase:

Allosteric effectors and covalent modification

58

Pyruvate kinase is more ________ when phosphoirylated

Inactive- under conditions of low BG

59

Pyruvate kinase is more ________ when dephosphorylated

ACTIVE - under conditions of high BG

60

Glucokinase has a ____ Km

High

= low affinity