[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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61

Hexokinase Km is significantly ________ than glucokinase

Lower

62

Fates of pyruvate

Lactate

TCA

-other micoorganisms can convert pyruvate to ethanol

63

What must occur before pyruvate can enter TCA cycle?

Pyruvate must undergo oxidative carboxylation to form acetyl CoA

64

Pyruvate can be reduced to lactate w/ the regeneration of:

NAD+

65

Precursor for pentose phosphate pathway

glucose-6-phosphate

66

Which organ(s)depends on glucose as primary fuel or only fuel

Brain and

RBCs- only use glucose

67

Brains daily glucose req'ment amt.:

Whole body req'ment:

120 g

160g

68

Glucose always has ____ g in body fluids, but there's about _____g available from glycogen

20 g;

190 g

69

How long would glucose reserves last a person?

About a day or so.

70

What bodily process is important during a long period of fasting or starvation?

Gluconeogenesis

71

Synthesis of glucose from noncarbohydrate precursors

Major precursors are lactate, AA's, and glycerol (but not FA's)

Pathways convert pyruvate to glucose

Pathway is not a reversal of glycolysis

Gluconeogenesis

72

Enzymes of irreversible reactions in the liver:

Glucokinase

Phosphofructokinase

Pyruvate kinase

73

What are the 4 enzymes used in gluconeogenesis to 'bypass' irreversible steps of glycolysis:

Pyruvate carboxylase (pyruvate->OAA)

Phosphoenolpyruvate carboxykinase (OAA->PEP)

Fructose-1,6-BPtase (F-1,6-BP->F-6-P)

Glucose-6-phosphatase (G-6-P->glu)

74

Regulation of pyruvate kinase:

Stimulated by insulin and F-1,6-BP

Inhibited by alanine, ATP, and glucagon

75

Stimulation of glucose-6-phosphatase

Stimulated by cortisol

76

Regulation of fructose-1,6-BPtase:

Stimulated by citrate and cortisol

Inhibited by AMP and F-2,6-BP

77

Regulation of PEP carboxylase

Stimulated by cortisol, glucagon, thyroxine

78

Regulation of pyruvate carboxylase

Stimulated by acetyl CoA and cortisol

Inhibited by ADP

79

First step of gluconeogenesis:

Pyruvate is converted to OAA

80

Source of OAA in gluconeogenesis:

How about pyruvate:

Some AA's source of OAA and pyruvate

Lactate also is a source of pyruvate


81

Generation of free glucose

For glucose to leave the liver the phosphate must be removed from glucose-6-phosphate

Which reaction? Enzyme?

G-3-P to glucose

Glucose 6-phosphatase

82

Where is glucose-6-phosphatase located?

In the lumen of the endoplasmic reticulum

83

G3P is transported to the ER by

A specific protein (T1) and another protein (T2) then transports glucose back to the cytoplasm

84

Glycolysis __________ ATP;

Gluconeogenesis __________ ATP

Generates;

Consumes

85

What is the best way to determine which pathway will be most active btw glycolysis and gluconeogenesis:

Energy charge (ATP/ADP ratio)

86

Gluconeogenesis and glycolysis are _____________ regulated

Reciprocally

87

Lactate produced in skeletal muscle and RBC's can be converted back to pyruvate in the liver

Cori cycle

88

What is the benefit of the cori cycle?

Since lactate is able to be converted back to pyruvate, the pyruvate can be used in gluconeogenesis to form glucose in times of low energy.