A. Why must a cell be made ‘competent’ in biotechnology experiments? How does calcium ion help in doing so?

B. State the role of ‘biolistic gun’ in biotechnology experiments.

A. In most biotechnology experiments the cells are made competent so that it can take up the DNA from the external medium. The bacterial cells are treated with divalent cations such as calcium to increase the efficiency of DNA entering the cell through pores in the cell wall.

B. Biolistic gun or gene gun is used to introduce alien DNA into host cells especially in plants. In this method, the host cells are bombarded with high-velocity microparticles of gold or tungsten coated DNA molecules.