Question

The phase generating additional circular DNA molecules in the first phase does it by __________

(a) bidirectional theta mode

(b) rolling circle mode

(c) separation of the two strands

(d) copying only one strand

This question was posed to me in an internship interview.

The doubt is from Bacteriophage Lambda in division Other Vector Systems for E of Genetic Engineering

Answer 1

Right choice is (a) bidirectional theta mode

The explanation is: The first phase includes circularization of the molecule by annealing of the cos sites and they replicate in a bidirectional theta mode. This leads to the generation of an additional circular DNA molecule.