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Biochem block 2 > Lecture4-GLUCONEOGENESIS > Flashcards

Lecture4-GLUCONEOGENESIS Flashcards

1
Q

Where is the location of gluconeogenesis taken place in the cell?

A

Starts in the mitochondria, then cytosol then ends in the ER lumen of the liver

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2
Q

what is the net product of gluconeogenesis?

A

-4ATP, -2 GTP, -2NADH
we are using energy to make glucose

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3
Q

What are the precursors of glucogensis

A

lactate, amino acids, glycerol

NOT ACTYL COA

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4
Q

Review: where is glycolysis located and net product?

A

Location: all cells, erythrocytes, brain and cns, muscle
net: +2ATP and +2 NADH

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5
Q

What is the rate limiting step for gluconeogenic pathway?

A

fructose 1-6 bisphosphate

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6
Q

What inhibits gluconeogenic pathway? with fructose 1-6 bisphosphatase

A

F2,6 BP

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7
Q

What activates the gluconeogenic pathway? with fructose 1-6 bisphosphatase

A

glucagon

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8
Q

What is the two spots you can inhibit the gluconeogenic pathway?

A

oxaloactate–> PEP with PEP carboxylokinase
F1,6BP –> F-6-P with F 1,6 Bisphosphatase

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9
Q

What activates gluconeogenic pathway? with PEP carboxykinase

A

glucagon

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10
Q

What inhibits gluconeogenic pathway? with PEP carboxykinase

A

insulin

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11
Q

Where is ATP and GTP used for gluconeogenesis? and the enzymes (lower yield)

A

Pyruvate to OAA with pyruvate carboxylase ( ATP)
3PG to 1-3BGP with phosphoglyerate kinase (ATP)
OAA to PEP with PEP carboxykinase (GTP)

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12
Q

Glucose 6-phosphate is located where?

A

on the luminal side of the ER in Liver

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13
Q

What happens in T1D?

A

lack of insulin

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14
Q

What happens in T2D? and with the gluconeogenic pathway

A

-insulin resistance
-cause the gluconeogeneis pathway to be uninhibited when when blood glucose concentration is high

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15
Q

What is the drug to treat T2D?

A

Metformin

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16
Q

How does metformin work?

A

stimulated liver AMP activated protein kinase which causes the inhibition of glucogenesis

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17
Q

what upregulates PEPCK?

A

glucagon

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18
Q

What inhibit PEPCK?

A

insulin

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19
Q

What is phosphorylated to start transcription of PEPCK?

A

CREB

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20
Q

What is a direct stimulator to start transcription of PEPCK?

A

glucocorticoid

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21
Q

F/T: breakdown of glycogen causes your blood sugar to rise

A

True

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22
Q

The muscle does not contain this enzyme that is found in the liver?

A

glucose 6-phosphatase

23
Q

what does the the liver do with Glucose 6 phosphatase

A

releases glucose to the blood to be taken up by brain and active muscle

24
Q

what does muscle do with glucose 6-phosphatase?

A

does not have It so it retains g-6-p to be used for energy (glycolysis)

25
Q

what is the cori cycle?

A

Lactate recycled from erythrocytes (or muscle cells) to liver

26
Q

what is the alanine cycle?

A

alanine recycled from muscle cells to liver

27
Q

What is the function of glycogen in the liver?

A

synthesis and breakdown of glycogen is regulated to maintain blood glucose levels

28
Q

What is the function of glycogen in the muscles?

A

the synthesis and breakdown of glycogen is regulated to meet the energy requirements of the muscle cell

29
Q

what is the RLE for glycogen metabolism?

A

glycogen synthase and glycogen phosphorylase

30
Q

where is glycogen stored?

A

liver, muscle and adipose tissue

31
Q

what is glycogenin?

A

OH linkage for additional linkages (1,4) and tyrosine residue as a primer

32
Q

What is the energy source for glycogen synthesis?

A

UDP-glucose

33
Q

is glycogenin and UDP self-glucosylating?

A

yes

34
Q

what adds the 1,4 linkages for glycogen synthesis?

A

glycogen synthase

35
Q

what adds the 1,6 linkages and what looks does it give?

A

branching enzyme and 3-D

36
Q

What is glycogenic-glycogen complex

A

final product with 1,4 and 1,6 linkages

37
Q

What linkage is hydrophobic and why?

A

1,4 linkages and because it lost two water molecules

38
Q

What does a cross-sectional of glycogen look like?

A

core protein of glycogenin is surround by branches of glucose units

39
Q

What contributes to blood glucose? and does not contribute

A

degradation of glycogen in liver contributes to blood glucose but not degradation of glycogen in muscles

40
Q

Why can the liver contribute to Blood glucose and muscles cannot?

A

liver has glucose 6 phosphatase to breakdown and muscle does not

41
Q

what happens when we degradate glycogen in our body

A

increase blood sugar levels

42
Q

what cleaves 1,4 linkages?

A

phosphorylase

43
Q

Transferase does what in degradation?

A

move everything except sugar connected to 1,6 linkage

44
Q

what cleaves 1,6 linkages ?

A

a-1,6 glucosidase

45
Q

what happens when blood glucose levels are high?

A

insulin stimulates glycogen synthesis

46
Q

what regulated blood glucose levels?

A

glycogen metabolism in liver

47
Q

what molecule are muscle cells responsive to for glycogen breakdown? what happens?

A

epinephrine
increase cAMP to get G-1-P–> G-6-P to get pyruvate for glycolysis since we do not have the enzyme

48
Q

what are liver cells responsive to for glycogen breakdown? what happens?

A

glycogen and somewhat epinephrine
increases cAMP–> G-1-P—> G-6-P to glucose

49
Q

what are glycogen storage diseases?

A

inborn errors of glycogen metabolism; deficiencies of enzymes necessary for glycogen synthesis or breakdown

50
Q

Von Gierke’s disease

A

glucose -6-phosphase deficiency
- final step in glyconegesis and glycogenolysis to produce glucose is defected
- growth failure, lactic acidosis, no pathologic muscle symptoms

51
Q

Cori’s disease

A

glycogen debranching enzyme deficiency
- defect in glycogenolysis
-myopathies

52
Q

Anderson disease

A

glycogen branching enzyme deficiency
- defect in glycogen synthesis
-failure to thrive
-death at about age 5 years
-no pathologic muscle symptoms

53
Q

McArdle disease

A

Glycogen phosphorylase deficiency
- defect in glycogenolysis
- exercise induced muscle cramps
-rhabdomyolysis (breakdown of damage skeletal muscle tissue)

Biochem block 2 (10 decks)

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