Proteins & Protein Metabolism (Biochemistry) BSc MCQs Set-1

Biochemistry Mcqs

1. All proteins contain the 

(A) Same 20 amino acids 
(B) Different amino acids 
(C) 300 Amino acids occurring in nature 
(D) Only a few amino acids 

Answer:(A) Same 20 amino acids 

2. Proteins contain

(A) Only L- α – amino acids 
(B) Only D-amino acids 
(C) DL-Amino acids 
(D) Both (A) and (B)

Answer:(A) Only L- α – amino acids

3. The optically inactive amino acid is 

(A) Glycine 
(B) Serine 
(C) Threonine 
(D) Valine

Answer: (A) Glycine

4. At neutral pH, a mixture of amino acids in solution would be predominantly: 

(A) Dipolar ions 
(B) Nonpolar molecules 
(C) Positive and monovalent 
(D) Hydrophobic

Answer: (A) Dipolar ions

5. The true statement about solutions of amino acids at physiological pH is 

(A) All amino acids contain both positive and negative charges
(B) All amino acids contain positively charged side chains 
(C) Some amino acids contain only positive charge 
(D) All amino acids contain negatively charged side chains

Answer: (A) All amino acids contain both positive and negative charges

6. pH (isoelectric pH) of alanine is 

(A) 6.02 
(B) 6.6 
(C) 6.8 
(D) 7.2

Answer: (A) 6.02

7. Since the pK values for aspartic acid are 2.0, 3.9 and 10.0, it follows that the isoelectric (pH) is 

(A) 3.0 
(B) 3.9
(C) 5.9 
(D) 6.0 

Answer: (A) 3.0

8. Sulphur containing amino acid is 

(A) Methionine 
(B) Leucine
(C) Valine 
(D) Asparagine

Answer: (A) Methionine

9. An example of sulphur containing amino acid is 

(A) 2-Amino-3-mercaptopropionic acid 
(B) 2-Amino-3-methylbutanoic acid 
(C) 2-Amino-3-hydroxypropanoic acid
(D) Amino acetic acid

Answer: (A) 2-Amino-3-mercaptopropionic acid

10. All the following are sulphur containing amino acids found in proteins except 

(A) Cysteine 
(B) Cystine 
(C) Methionine 
(D) Threonine

Answer: (D) Threonine

11. An aromatic amino acid is 

(A) Lysine 
(B) Tyrosine
(C) Taurine 
(D) Arginine

Answer: (B) Tyrosine

12. The functions of plasma albumin are 

(A) Osmosis 
(B) Transport 
(C) Immunity 
(D) both (A )and (B) 

Answer: (A) Osmosis

13. Amino acid with side chain containing basic groups is

(A) 2-Amino 5-guanidinovaleric acid 
(B) 2-Pyrrolidine carboxylic acid 
(C) 2-Amino 3-mercaptopropionic acid 
(D) 2-Amino propanoic acid 

Answer: (A) 2-Amino 5-guanidinovaleric acid

14. An example of α-amino acid not present in proteins but essential in mammalian metabolism is 

(A) 3-Amino 3-hydroxypropanoic acid 
(B) 2-Amino 3-hydroxybutanoic acid 
(C) 2-Amino 4-mercaptobutanoic acid 
(D) 2-Amino 3-mercaptopropionic acid

Answer: (C) 2-Amino 4-mercaptobutanoic acid 

15. An essential amino acid in man is 

(A) Aspartate 
(B) Tyrosine
(C) Methionine
(D) Serine 

Answer: (C) Methionine

16. Non essential amino acids 

(A) Are not components of tissue proteins 
(B) May be synthesized in the body from essential amino acids 
(C) Have no role in the metabolism 
(D) May be synthesized in the body in diseased states

Answer: (B) May be synthesized in the body from essential amino acids

17. Which one of the following is a semi essential amino acid for humans? 

(A) Valine 
(B) Arginine 
(C) Lysine 
(D) Tyrosine 

Answer: (B) Arginine

18. An example of polar amino acid is 

(A) Alanine 
(B) Leucine 
(C) Arginine 
(D) Valine

Answer: (C) Arginine

19. The amino acid with a nonpolar side chain is

(A) Serine
(B) Valine 
(C) Asparagine 
(D) Threonine

Answer: (B) Valine

20. A ketogenic amino acid is 

(A) Valine 
(B) Cysteine 
(C) Leucine 
(D) Threonine

Answer: (C) Leucine

21. An amino acid that does not form an αhelix is 

(A) Valine 
(B) Proline 
(C) Tyrosine 
(D) Tryptophan

Answer: (B) Proline

22. An amino acid not found in proteins is

(A) β-Alanine 
(B) Proline 
(C) Lysine 
(D) Histidine

Answer: (A) β-Alanine

23. In mammalian tissues serine can be a biosynthetic precursor of 

(A) Methionine 
(B) Glycine 
(C) Tryptophan 
(D) Phenylalanine 

Answer: (B) Glycin

24. A vasodilating compound is produced by the decarboxylation of the amino acid:

(A) Arginine 
(B) Aspartic acid 
(C) Glutamine 
(D) Histidine 

Answer: (D) Histidine

25. Biuret reaction is specific for 

(A) –CONH-linkages 
(B) –CSNH2 group 
(C) –(NH)NH2 group 
(D) All of these 

Answer: (A) –CONH-linkages

26. Sakaguchi’s reaction is specific for 

(A) Tyrosine 
(B) Proline 
(C) Arginine 
(D) Cysteine 

Answer: (C) Arginine

27. Millon-Nasse’s reaction is specific for the amino acid:

(A) Tryptophan 
(B) Tyrosine 
(C) Phenylalanine 
(D) Arginine

Answer: (B) Tyrosine

28. Ninhydrin with evolution of CO2 forms a blue complex with 

(A) Peptide bond 
(B) α-Amino acids
(C) Serotonin 
(D) Histamine

Answer: (B) α-Amino acids

29. The most of the ultraviolet absorption of proteins above 240 nm is due to their content of 

(A) Tryptophan
(B) Aspartate 
(C) Glutamate 
(D) Alanine 

Answer: (A) Tryptophan

30. Which of the following is a dipeptide? 

(A) Anserine 
(B) Glutathione 
(C) Glucagon 
(D) β -Lipoprotein 

Answer: (A) Anserine