Ligation is defined as ______________

a) Alignment of only double stranded DNA molecules at the ends and the formation of phosphodiester bonds between both the strands

b) Alignment of either of the double or single stranded DNA molecules and formation of glycosidic bonds between both the strands

c) Alignment of either of the double or single stranded DNA molecules and the formation of phosphodiester bonds. The bond can be between either one or both the strands

d) Alignment of single stranded DNA molecules and formation of glycosidic bonds between these strands

2. If only one bond is broken in the sugar-phosphate backbone, it is called as ___________

a) gap

b) nick

c) break

d) leakage

3. How many categories of ligation reaction are there on the basis of ends created?

a) 1

b) 2

c) 3

d) 4

4. In the case of blunt-end ligation, blunt ends can be generated by ___________

a) simply the action of restriction endonuclease which gives straight ends

b) the polishing of staggered ends

c) both the action of restriction endonuclease which gives straight ends and polishing of staggered ends

d) by the action of restriction endonuclease which gives staggered ends

5. The ligation reaction is more efficient in which case?

a) Blunt end ligation

b) Sticky end ligation

c) Both have the same efficiency

d) Depends on the reaction conditions

6. The sticky ends are held together by which type of bonds?

a) Hydrogen bond

b) Covalent bond

c) Ionic bond

d) Van-der-waal forces

7. Why sticky ended ligations are carried out at temperatures lower than room temperature?

a) It is so because the vibrational and kinetic energy of the molecules at room temperature is lower than that of the energy required to break the bonds holding the ends

b) The energy required to break the bonds holding the ends is very less than that of the kinetic and vibrational energy at room temperature

c) The enzyme carrying out ligation is unstable at low temperature

d) The sticky ends created, don't just relegate at low temperature

8. Ligation reaction can be both intramolecular and intermolecular in nature.

a) True

b) False

9. If a ligation reaction is being carried out and recircularization is observed, which type of reaction is being carried out?

a) Intramolecular

b) Intermolecular

c) Both observe recircularization equally

d) Recirculation is not possible in any of the cases