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(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. |
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Answer» (a) (i) To take up the (hydrophilic) DNA from the external medium. (ii) Divalent calcium ions increase the efficiency the cell through pores in the cell wall. (b) To introduce alien DNA into the plant cell by bombarding them with high velocity microparticles (gold or tungsten coated with DNA). Detailed Answer : (a) In biotechnology experiments, the cells must be made competent so that they can take up the hydrophilic DNA molecule inside them from the external medium. Treatment of bacterial cells with divalent calcium cations makes them competent and helps them to take up the DNA through the pores in the cell wall. (b) Biolistic gene or gene gun is a method of introducing alien DNA into the plants cells. In this method, the host cells are bombarded with high velocity micro-particles of gold and tungsten coated with DNA molecules. |
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