31. Nitrogen Metabolism Flashcards

1
Q

protein turnover is

A

300-400 g per day

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2
Q

amount of protein degraded and resynthesized from amino acids

A

protein turnover

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3
Q

sum of all free amino acids in cells and extracellular fluid

A

amino acid pool

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4
Q

sources of amino acid pool

A
  • degradation and turnover of body protein
  • dietary intake
  • synthesis of nonessential amino acids
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5
Q

first phase of amino acid catabolism involves

A

•transamination -aminotransferase, pyridoxal phosphate
•oxidative deamination
-glutamate dehydrogenase

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6
Q

second phase of AA catabolism

A
  • carbon skeletons of alpha keto acids converted to intermediates of
  • glycolysis
  • krebs cycle
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7
Q

excretion of excess nitrogen by humans as non toxic , water soluble urea

A

ureotelic

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8
Q

birds, who excrete uric acid as semisolid guano

A

uricotelic

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9
Q

seen in telostean fish, which excrete highlyy toxic ammonia

A

ammonotelic

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10
Q

Transamination of amino acids

enzyme and coenzyme

A

enzyme: aminotransferase
coenzyme: pyridoxal phosphate

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11
Q

all amino acids transfer their alpha amino group to alpha ketoglutarate –> glutamate
EXCEPT

A

Lysine
Threonine
Proline
Hydroxyproline

KTP + Hyp

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12
Q
  1. oxidative deamination of glutamate
A

L-glutamate –> alpha ketoglutarate
+ NH3
(glutamate dehydrogenase)
to release ammonia

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13
Q

glutamate +ammonia

requires this enzyme

A

glutamine synthase

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14
Q

glutamine is deaminated to release ammonia in 2 organs

and through what enzyme

A

liver - high protein intake
kidneys - response to metabolic acidosis

enzyme: glutaminase

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15
Q

In muscle, ammonia is released through

A

pyruvate transaminated to alanine

alanine -> liver -> pyruvate

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