Question

(a) Why should a bacteria be made 'competent'?

(b) Explain the role of 'microinjection' and 'gene gun' in biotechnology. [3 Marks]

Answer 1

(a) Bacteria can not take up foreign DNA naturally from the surroundings.This is because DNA is a hydrophobic molecule and cannot pass through the membrane. Hence we have to make the cell competent or able to take up foreign DNA. [1 Mark]

(b) Microinjection and gene gun are ways of introducing foreign DNA into cells.
Microinjection : recombinant DNA is directly injected into the nucleus of an animal cell. [1 Mark]

Gene gun: method suitable for transformation of plants where cells are bombarded with high velocity micro-particles of gold or tungsten coated with DNA using a biolistic or gene gun. [1 Mark]