Amino Acid Catabolism

Question 1

Amino acids that have more than one catabolic pathway

Glycogenic and ketogenic

Answer 1

Isoleucine
Phenylalanine
Tryptophan
Tyrosine

Question 2

Ammoniotelic

Answer 2

Excreted as ammonia

Toxic; fish

Question 3

Uricotelic

Answer 3

Uris acid

Insoluble; birds

Question 4

Ureotelic

Answer 4

Urea

Water soluble; most terrestrial animals

Question 5

Link between urea cycle and citric acid cycle

Answer 5

Fumarate
Oxaloacetate -> aspartate
a-ketoglutamate -> glutamate

Question 6

Urea acid cycle amino group transferred to

Answer 6

a-ketoglutarate from glutamate (transamination)

Question 7

Fates of carbon skeleton in urea cycle

Answer 7

Pyruvate or oxaloacetate (gluconeogenesis)

Acetyl-CoA or acetoacetyl-CoA (can form lipids)

Question 8

Precursor of urea

Answer 8

Arginine

Question 9

Source of nitrogen in urea cycle

Answer 9

Glutamate
Using gutamate dehydrogenase
(Second nitrogen comes from Aspartate amino group)

Question 10

Committed step of urea cycle

Answer 10

Formation of carbomylphosphate 
Catalysed by (CPS-1)
Activated by high [arginine]
Produces N-acetylglucamate
-using N-acetylglucamate synthase

Question 11

Committed urea cycle equation

Answer 11

Glutamate + acetyl-CoA —> N-Acetylglutamate

Question 12

Ketogenic amino acids

Answer 12

Leucine

Lysine

Question 13

Carbomylphosphate production enzymes

Answer 13

Carbomylphosphate synthetase 1 (CPS-1)