Question

What happens after packaging is carried out in the phage head?

(a) A sequence dependent cleavage of DNA is carried out

(b) A sequence independent cleavage of DNA is carried out

(c) They are linearized before they are infected into the bacterial cells

(d) They are circularized before they are infected into the bacterial cells

This question was posed to me by my college professor while I was bunking the class.

Query is from Bacteriophage-Mu and Bacteriophage-Pi in section Other Vector Systems for E of Genetic Engineering

Answer 1

Correct option is (b) A sequence independent cleavage of DNA is carried out

The explanation: After the packaging is carried out in the phage head, a sequence independent cleavage of DNA is carried out. Molecules with a very small size insert can’t fill into the whole phage head before the next pac site is reached.