Catabolism for energy production

Question 1

amino acid uptake and catabolism occurs mainly where?

Answer 1

in the liver (only partial oxidation)

Question 2

where can oxidation of amino acids occur? (get ATP from amino acids)

Answer 2

• liver
• muscles
• jejenum

Question 3

branched-chain amino acids are catabolized _________ in the liver than in the muscles.

Answer 3

SLOWER

Question 4

In the liver, which amino acids are uptaken alot (high uptake) and which are not taken up as much (lower uptake)

Answer 4

Alanine and serine= high uptake

Aspartate and glutamate = low uptake

Question 5

what is transamination?

Answer 5

Transamination is the transfer of amino group to an a-keto acid to form another amino acid by the enzyme aminotransferase/transaminase.

Question 6

which are the most active aminotransferases??

Answer 6

alanine and aspartate aminotransferase

Question 7

what amino acid is formed by pyruvate? oxaloacetate?

Answer 7

alanine from pyruvate

aspartate from oxaloacetate

Question 8

which a.a’s do not participate directly in transamination?

Answer 8

lysine, tryptophan, proline, arginine

Question 9

what is deamination? is it common?

Answer 9

Deamination is removal of an a-amino group from amino acid to release NH3 and form a keto acid. It is less common than transamination

Question 10

what is the most common deamination in the body?

Answer 10

conversion of glutamate to a-ketoglutarate and NH3 (catalyzed by glutamate dehydrogenase)

Question 11

where is glutamate dehydrogenase present in high activity?

Answer 11

liver, brain and kidney cortex

Question 12

How is ammonia (NH3) disposed of in the liver, brain and kidney??

Answer 12

liver: NH3–> Urea
brain: NH3–> glutamine
kidney: NH3–> excreted in urine

Question 13

which amino acid is involved in ammonia transport?

Answer 13

Glutamine

Question 14

what is the carbon skeleton of amino acids used for?

Answer 14

• energy (when diets low carbs)
• keton bodies
• fatty acids

Question 15

what is ureagenesis?

Answer 15

Formation of urea by the metabolism of amino acids to urea

Question 16

what is the role of aspartate in ureagenesis?

Answer 16

serves as 2-carbon donor for ureagenesis

Question 17

catabolism of ketogenic amino acids produces what?

Answer 17

acetyl CoA or acetoacetate

Question 18

what are the only totally ketogenic amino acids?

Answer 18

lysine and leucine

Question 19

which amino acids are both gluconeogeneic and ketogeneic?

Answer 19

threonine
isoleucine
phenylalanine
tryptophan
tyrosine

Question 20

which amino acids are gluconeogenic?

Answer 20

Glycine, serine, valine, histidine, arginine, cysteine, proline, alanine, glutamate, glutamine, aspartate, asparagine, methinoine

Question 21

which groups of amino acids are likely to be metabolized into pyruvate?

Answer 21

Alanine, cysteine, glycine, serine, threonine, & tryptophan

Question 22

which amino acids are likely to be metabolized into a-ketoglutarate?

Answer 22

arginine, glutamate, glutamine, histidine, proline

Question 23

which amino acids are metabolized into succinyl-CoA ?

Answer 23

isoleucine, methionine, threonine, valine

Question 24

which amino acids are metabolized into fumarate?

Answer 24

phenylalanine, tyrosine

Question 25

which amino acids are metabolized into oxaloacetate?

Answer 25

asparasgine and aspartate