(A) Vitamin A
(B) Vitamin C
(C) Vitamin E
(D) Vitamin B12
The rate limiting step in the biosynthesis of catecholamines is?
(A) Decarboxylation of dihydroxyphenylalanine
(B) Hydroxylation of phenylalanine
(C) Hydroxylation of tyrosine
(D) Oxidation of dopamine
Conversion of tyrosine to dihydroxyphenylalanine is catalysed by tyrosine hydroxylase which requires?
(A) NAD
(B) FAD
(C) ATP
(D) Tetrahydrobiopterin
Tryptophan could be considered as precursor of?
(A) Melanotonin
(B) Thyroid hormones
(C) Melanin
(D) Epinephrine
In carcinoid syndrome the argentaffin tissue of the abdominal cavity overproduce?
(A) Serotonin
(B) Histamine
(C) Tryptamine
(D) Tyrosine
The 2 nitrogen atoms in urea are contributed by?
(A) Ammonia and glutamate
(B) Glutamine and glutamate
(C) Ammonia and aspartate
(D) Ammonia and alanine
A compound serving a link between citric acid cycle and urea cycle is?
(A) Malate
(B) Citrate
(C) Succinate
(D) Fumarate
Transfer of the carbamoyl moiety of carbamoyl phosphate to ornithine is catalysed by a liver mitochondrial enzyme:
(A) Carbamoyl phosphate synthetase
(B) Ornithine transcarbamoylase
(C) N-acetyl glutamate synthetase
(D) N-acetyl glutamate hydrolase