MCQs

PROTEINS

Dr. RUCHIKA YADU

Q1. The repeating units of

proteins are

a) glucose units

b) amino acids

c) fatty acids

d) peptides

Q2. Amino acids are joined by

a) peptide bond

b) hydrogen bond

c) ionic bond

d) glycosidic bond

Q3. The primary structure of

protein represents

a) Linear sequence of amino acids joined by

peptide bond

b) 3-dimensional structure of protein

c) helical structure of protein

d) sub unit structure of protein

Q4. Amino acids has

a) both amino group and carboxyl group

b) both amino group and keto group

c) amino group only

d) carboxyl group only

Q5. The simplest amino acid is

a) Proline

b) methionine

c) glycine

d) serine

Q6. The first amino acid in a

polypeptide chain is

a) Serine

b) Valine

c) Alanine

d) Methionine

Q7. Aromatic amino acids

include

a) Phenylalanine, tyrosine and tryptophan

b) Phenylalanine, serine and tryptophan

c) Threonine, tyrosine and tryptophan

d) Asparagine, tyrosine and tryptophan

Q8. Positively charged basic

amino acids are

a) Lysine and arginine

b) Lysine and asparagine

c) Glutamine and arginine

d) Lysine and glutamine

Q9. Acidic amino acids include

a) Arginine and glutamate

b) Aspartate and asparagine

c) Aspartate and lysine

d) Aspartate and glutamate

Q10. All of the following are

essential amino acids except

a) Lysine

b) Aspartate

c) Tryptophan

d) Histidine

Q11. Haemoglobin has

a) primary structure

b) secondary structure

c) tertiary structure

d) quaternary structure

Q12. A dipeptide has

a) 2 amino acids and 1 peptide bond

b) 2 amino acids and 2 peptide bonds

c) 2 amino acids and 3 peptide bonds

d) 2 amino acids and 4 peptide bonds

Q13. Which of the following statements is/are

true regarding primary structure of proteins

a) Primary structure denote the number of amino acids

in a protein

b) Primary structure denote the sequence of amino

acids in a protein

c) Primary structure determines the biological activity

of a protein

d) all of these

Q14. Which of the following statements is true

regarding quaternary structure of proteins

a) Refers to organization and spatial arrangements

of amino acids within a polypeptide chain

b) Refers to organization and spatial arrangements

of proteins with many polypeptide chains

c) Both a and b

d) None of these

Q15.Which type of bonding is responsible

for stabilizing the secondary structure of

proteins?

a) Disulphide bridges between cysteine residues.

b) Hydrogen bonding between the C=O and N-H

groups of peptide bonds.

c) Peptide bonds between amino acids.

d) Salt bridges between charged side chains of

amino acids.

Q16. A coiled peptide chain held in place by

hydrogen bonding between peptide bonds in the

same chain is

a) Primary structure

b) α-helix

c) β-pleated sheets

d) Tertiary structure

Q17. A structure that has hydrogen bonds

between polypeptide chains arranged side by

side is

a) Primary structure

b) α-helix

c) β-pleated sheets

d) Tertiary structure

Q18. In alpha helix, the bonding is

between the

a) Adjacent amino acids

b) Carbonyl oxygen of one peptide bond to the NH group of the 4th amino acid away

c) Carbonyl oxygen of second peptide bond to the NH group of the 3rd amino acid away

d) Carbonyl oxygen of second peptide bond to the NH group of the 5th amino acid away

Q19. The primary structure is

primarily maintained by

a) Peptide bond

b) Hydrogen bond

c) Ionic bond

d) Hydrophobic bonds

Q20. The secondary structure is

primarily maintained by

a) Van der waals force

b) Hydrogen bond

c) Ionic bond

d) Hydrophobic bonds

Q21. Which of the following is the most

common and stable conformation for a

polypeptide chain

a) Alpha helix

b) Beta pleated sheets

c) Anti parallel beta pleated sheet

d) Tertiary structure

Q22. Amino acids with hydroxyl

groups are

a) serine and alanine

b) Alanine and valine

c) serine and threonine

d) Valine and isoleucine

Q23. The naturally occurring

form of amino acid in proteins

a) L-amino acids only

b) D-amino acids only

c) both L and D amino acids

d) none of these

Q24. Sulphur containing amino

acids are

a) Cysteine and methionine

b) Methionine and threonine

c) Cysteine and threonine

d) Cysteine and serine

Q25. Tertiary structure is

maintained by

a) peptide bond

b) hydrogen bond

c) di-sulphide bond

d) all of the above

Ques. Option Answer

1 b amino acids

2 a peptide bond

3 a Linear sequence of amino acids joined by peptide bond

4 a both amino group and carboxyl group 5 c glycine 6 d Methionine7 a Phenylalanine, tyrosine and tryptophan

8 a Lysine and arginine

9 d Aspartate and glutamate

10 b Aspartate

11 d quaternary structure

12 a 2 amino acids and 1 peptide bond

13 d all of these

14 b Refers to organization and spatialarrangements of proteins with manypolypeptide chains

15 b Hydrogen bonding between the C=O and N-H groups of peptide bonds.

16 b α-helix17 c β-pleated sheets

18 b Carbonyl oxygen of one peptidebond to the NH group of the4th amino acid away

19 d Hydrophobic bonds

20 b Hydrogen bond

21 a Alpha helix

22 c serine and threonine

23 a L-amino acids only

24 a Cysteine and methionine

25 d all of the above