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PROTEINS AND PROTEIN METABOLISM- Part 4
See all quizzes of PROTEINS AND PROTEIN METABOLISM- Part 4 here:
1 Pepsinogen is converted to active pepsin
by
(A) HCl (B) Bile salts
(C) Ca++ (D) Enterokinase
2. The optimal pH for the enzyme rennin is
(A) 2.0 (B) 4.0
(C) 8.0 (D) 6.0
3. The optimal pH for the enzyme trypsin is
(A) 1.0–2.0 (B) 2.0–4.0
(C) 5.2–6.2 (D) 5.8–6.2
4. The optimal pH for the enzyme chymotrypsin
is
(A) 2.0 (B) 4.0
(C) 6.0 (D) 8.0
5 Trypsinogen is converted to active trypsin
by
(A) Enterokinase (B) Bile salts
(C) HCl (D) Mg++
6 Pepsin acts on denatured proteins to
produce
(A) Proteoses and peptones
(B) Polypeptides
(C) Peptides
(D) Dipeptides
7. Renin converts casein to paracasein in
presence of
(A) Ca++ (B) Mg++
(C) Na+ (D) K+
8. An expopeptidase is
(A) Trypsin (B) Chymotrypsin
(C) Elastase (D) Elastase
9. The enzyme trypsin is specific for peptide
bonds of
(A) Basic amino acids
(B) Acidic amino acids
(C) Aromatic amino acids
(D) Next to small amino acid residues
10. Chymotrypsin is specific for peptide bonds
containing
(A) Uncharged amino acid residues
(B) Acidic amino acids
(C) Basic amino acid
(D) Small amino acid residues
11. The end product of protein digestion in
G.I.T. is
(A) Dipeptide (B) Tripeptide
(C) Polypeptide (D) Amino acid
12. Natural L-isomers of amino acids are
absorbed from intestine by
(A) Passive diffusion (B) Simple diffusion
(C) Faciliated diffusion(D) Active process
13. Abnormalities of blood clotting are
(A) Haemophilia (B) Christmas disease
(C) Gout (D) Both (A) and (B)
14. An important reaction for the synthesis
of amino acid from carbohydrate
intermediates is transamination which
requires the cofactor:
(A) Thiamin (B) Riboflavin
(C) Niacin (D) Pyridoxal phosphate
PROTEINS AND PROTEIN METABOLISM 33
15. The main sites for oxidative deamination
are
(A) Liver and kidney
(B) Skin and pancreas
(C) Intestine and mammary gland
(D) Lung and spleen
16. A positive nitrogen balance occurs
(A) In growing infant
(B) Following surgery
(C) In advanced cancer
(D) In kwashiorkar
17. The main site of urea synthesis in mammals
is
(A) Liver (B) Skin
(C) Intestine (D) Kidney
18. The enzymes of urea synthesis are found
in
(A) Mitochondria only
(B) Cytosol only
(C) Both mitochondria and cytosol
(D) Nucleus
19. The number of ATP required for urea
synthesis is
(A) 0 (B) 1
(C) 2 (D) 3
20. Most of the ammonia released from L-α-
amino acids reflects the coupled action of
transaminase and
(A) L-glutamate dehydrogenase
(B) L-amino acid oxidase
(C) Histidase
(D) Serine dehydratase
21. In urea synthesis, the amino acid functioning
solely as an enzyme activator:
(A) N-acetyl glutamate (B) Ornithine
(C) Citrulline (D) Arginine
22. The enzyme carbamoyl phosphate
synthetase requires
(A) Mg++ (B) Ca++
(C) Na+ (D) K+
23. Control of urea cycle involves the enzyme:
(A) Carbamoyl phosphate synthetase
(B) Ornithine transcarbamoylase
(C) Argininosuccinase
(D) Arginase
24. 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
25. A compound serving a link between citric
acid cycle and urea cycle is
(A) Malate (B) Citrate
(C) Succinate (D) Fumarate
26. 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
27. In carcinoid syndrome the argentaffin
tissue of the abdominal cavity overproduce
(A) Serotonin (B) Histamine
(C) Tryptamine (D) Tyrosine
28. Tryptophan could be considered as
precursor of
(A) Melanotonin (B) Thyroid hormones
(C) Melanin (D) Epinephrine
29. Conversion of tyrosine to dihydroxyphenylalanine
is catalysed by tyrosine hydroxylase
which requires
(A) NAD (B) FAD
(C) ATP (D) Tetrahydrobiopterin
30. 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
