Question

Choose the incorrect statement with respect to the collection of single stranded molecules.

(a) An infected culture is set up and after a while the cells are removed by centrifugation

(b) The phage is in the supernatant and is precipitated by addition of glycol and sodium chloride

(c) The phage pellet is resuspended and phenol is used for removal of protein

(d) The single stranded molecules sediment at the bottom

This question was posed to me in an interview for internship.

The query is from BAC Vector, M13 and its Derivatives in chapter Other Vector Systems for E of Genetic Engineering

Answer 1

The correct answer is (d) The single stranded molecules sediment at the bottom

Easiest explanation: The collection of single stranded molecules is slightly different. An infected culture is set up and after a while cells are removed by centrifugation. The phage is present in the supernatant and is precipitated by addition of glycol and sodium chloride. It is followed by centrifugation. The phage pellet is resuspended and phenol is used for removal of protein. The single stranded molecules remain in the solution and thus can be precipitated further.