Multiple Choice on Proteins

1. The repeating units of proteins are

a) glucose units

b) amino acids

c) fatty acids

d) peptides

2. Amino acids are joined by

a) peptide bond

b) hydrogen bond

c) ionic bond

d) glycosidic bond

3. 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

4. Peptide bond is

a) rigid with partial double bond character

b) planar, covalent

c)  covalent

d) all of the above

5. Enzymes are

a) proteins

b) carbohydrates

c) nucleic acids

d) DNA molecule

6. The first protein sequenced by Frederick Sanger is

a) Haemoglobin

b) myoglobin

c) insulin

d) myosin

7. 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

8. The most common secondary structure is

a) α-helix

b) β-pleated sheet

c) β-pleated sheet parallel

d) β-pleated sheet non parallel

9. Myoglobin is a

a) protein with primary structure

b) protein with secondary structure

c) protein with tertiary structure

d) protein with quaternery structure

10. Fibrous protein such as silk fibroin consists of polypeptide chains arranged in

a) α-helix

b) β-pleated sheet

c) β-helix

d) none of these

11. α-helix has

a) 3.4 amino acid residues/turn

b) 3.6 amino acid residues/turn

c) 3.8 amino acid residues/turn

d) 3.0 amino acid residues/turn

12. Tertiary structure is maintained by

a) peptide bond

b) hydrogen bond

c) di-sulphide bond

d) all of the above

13. Haemoglobin has

a)  primary structure

b)  secondary structure

c)  tertiary structure

d) quaternery structure

14. Disulphide bonds are formed between

a) cysteine residues that are close together

b) cystine residues that are close together

c) proline residues that are close together

d) histidine residues that are close together

15. The 3-D structure of protein can be determined by

a) Nuclear magnetic resonance

b) X-ray crystallography

c) both a and b

d) Spectroscopy

Answers

1-b	2-a	3-a	4-d	5-a
6-c	7-a	8-a	9-c	10-b
11-b	12-d	13-d	14-a	15-c