Q17 of 51 Page 1

A. How do organic farmers control pests? Give two examples.

B. State the difference in their approach from that of conventional pest control methods.

A. Organic farmers control pests using natural predation or biological control. Examples are Bacillus thuringiensis is used to kill cotton bollworm, dragon flies used to kill mosquitoes, lady bird used to kill aphids, etc.

B. The conventional pest control uses insecticides and pesticides which kill insects and pests. Since these chemicals are non-biodegradables causes environmental pollution and bio magnification. Whereas organic farmers do not try to completely get rid of pests but keep them at manageable levels. The complete eradication of pests is not beneficial for ecosystem.


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15

A. It is generally observed that the children who had suffered from chicken – pox in their childhood may not contract the same disease in their adulthood. Explain giving reasons the basis of such an immunity in an individual. Name this kind of immunity.

B. What are interferons? Mention their role.

 16

A. Write the two limitations of traditional breeding technique that led to the promotion of micropropagation.

B. Mention two advantages of micro propagation.


C. Give two examples where it is commercially adopted.

 18

A. Name the selectable markers in the cloning vector pBR322? Mention the role they play.

B. Why is the coding sequence of an enzyme β-galactosidase a preferred selectable marker in comparison to the ones named above?

 19

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.