Amino Acid Metab and Urea Cycle Flashcards Preview

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Flashcards in Amino Acid Metab and Urea Cycle Deck (102)
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1

 concentration of free amino acids is higher in the cell or out of the cell?

intracellular concentration is ocnsiderably higher

 this gradient is maintained by active transport of amino acids into cells

2

the intracellular/extracellular free AA gradient varies with different AA, the greatest with 

glutamate and glutamine.

3

** what are the most abundant amino acids in serum.

Glutamine and alanine

4

In the body there is about 100g of free amino acids.

how much is glutamate and glutamine?

how much is essential AA? 

50% -- glutamate, gluatmine

10% -- essential AA

5

*********

What are the essenital AA? 

"Pvt. Tim Hall"

 

Phenylalnine
Valine
Trptophan

Threonine
Isoleucine
Methionine

Histidine
Arginine
Leucine
Lysine

6

____ becomes essential if methionine is low 

Cysteine

7

_____ becomes essential if phenylalanine is low.

tyrosine

8

essential AA for growth?

arginine

9

inputs into the AA pool are from

 dietary protein and proteolysis of cellular protein

10

Approximately half the endogenous protein (6-7kg) is associated with

 the skeleton and other supporting tissues

(Of which the major protein component is collagen)

11

Gastrointestinal inputs 

70-100g of dietary protein and 35-200g of endogenous protein from sloshed off____ absorbed daily.

 intestinal cells

12

 Disorders associated with defects in amino acid transport lead to 

increased levels of these amino acids in the urine,

13

Disorders associated with defects in amino acid transport

prognosis?

these disorders are benign or cause only minor health problems, since amino acids are also absorbed from the intestines as small peptides

14

___ separate transporters of AA from the gut into intestinal epithelial cells

FIVE

15

transport of amino acids from the gut into intestinal epithelial cell all are ___ symporters

NA or PROTON SYMPORTERS

16

High degree of redundancy with ___ since they overlap considerably in their specifity

AA transporters from gut to intestinal epithelial cells

17

what is the defect involved in Hartnup’s Disease??

A defect in the transport system for neutral and aromatic amino acids from the gut and the renal tubules

18

Hartnup’s Disease sx? 

 4D’s: Diarrhea, Dermatitis, Dementia, Death)

19

Hartnup’s Disease tx? 

administration of niacin

20

how is Hartnup’s Disease dx?

diarrhea, dermatitis, dementia, death with HIGH LEVELS OF NEUTRAL OR AROMATIC AA IN URINE

21

what is the defect in Cysinuria? 

A defect in the transport system for basic amino acids and cystine (a disulfide- linked dimer of cysteine) from the gut and the renal tubules.

22

Cystinuria sx? 

crystals formed by cystine can lead to UTI AND KIDNEY STONES

23

Cystinuria tx? 

fluids, and administration of the drug penicillamine (reacts with cystine to form a significantly more soluble compound)

24

where is trancytosis along the brush border most pronounced? 

in infants where it enables them to acquire antibodies from breast milk.

25

Cystic Fibrosis Because of a defect in the chloride channels in the pancreatic secretory ducts, what do these pts need to be given? 

secretory ducts harden, so need pancreatic enzymes

26

when is body protein being broken down to free AA?

continuously

 

 The rate of this proteolysis varies widely between proteins from half lives of a few minutes to years.

27

The urinary levels of ____ can provide a measure of muscle protein breakdown.

3-methyl histidine

it is liberated when actomyosin is broken down. histidine residues of muscle are methylated posttranslationally 

28

Metabolic breakdown of amino acids to urea and CO2 is a continuous drain. This is reduced during

 starvation, but is never turned off. 

29

___ and ___ provide complementing essential amino acids.

Grains and beans

30

Normal nitrogen balance (in a healthy person) 

total daily N intake = totai daily N loss (in urine, skin feces)