IV. Answer the following short questions yourself.

Q1. What are steps involved in restriction digestion by type II restriction enzymes?

Q2 . Write different functions of Polynucleotide phosphorylase enzyme.

Q3. Define methyltransferase enzymes. Write different classes of methyltransferase enzymes based on their activity?

Q4. Write a short note on RNaseA.

V. Answer the following long questions yourself.

Q1. Define restriction enzyme. What are the types of restriction enzyme and compare their properties.

Q2. Define deoxyribonuclease enzymes. Discuss different types of deoxyribonuclease enzymes.

Q3. Write a short note on alkaline phosphatase enzymes. Discuss different types of alkaline phosphatase enzymes.

Q4. Discuss the mechanism of action of ligase enzyme with diagram.

ANSWERS

I. Choose the correct answer.

1. (B) Mg²⁺

2. (C) Endonuclease

3. (D) phosphodiester bond

4 . (B) 3'→ 5' exonuclease activity

5. (D) 3-6 pH

6. (B ) 60°C

7. (D ) ammonium ion

II. Fill in the blanks with appropriate words and terminology.

1. Restriction enzyme, 2. Discovered, letters and numbers, 3. Sticky end or blunt end 4. Polynucleotide phosphorylase, 5. Deoxyribonuclease, 6. 3'→5' exonuclease, 7. Mung bean, 8. Phosphatase, 9. Acid phosphatase, 10. Alkaline phosphatase, 11. Methyltransferase or methylase, 12. DNA ligase, 13. NAD ⁺ , 14. ATP, 15. Polynucleotide kinase.