CBSE 2022 · Region 1 · Set 3 · Q13 · 5 marks

To save the crop plant from the attack of various insect pests the biotechnologists have developed many pest resistant plants. One such example is Bt corn plant. In this plant 'cry' genes were introduced which produces cry-proteins in the plant that has toxic effect on the pest (corn borer). Thus saves the corn plant from the attack of the corn borer. An experimental field study was conducted by the scientists to see the efficacy of the Bt corn plant against the attack of corn borers. Three different species of corn borers namely 'A', 'B', 'C' were collected and were independently fed on non Bt corn plants and Bt corn plants separately for the same period. The extent of the damage caused to the leaf area of the plant was observed and noted down. With the help of the observations and data collected the following bar graph was plotted. Study the graph and answer the questions that follow.

(i)

Identify the species of the corn borer that was most successfully controlled by Bt corn plant. Give appropriate reason for your inference.

(ii)

Identify the species of the corn borers which shows least impact of toxin produced by Bt genes.

(iii)

What would be your advise as a Scientist, to the farmers for growing this particular Bt corn variety in the area which is infested by species-'B' of corn borers ?

(iv)

Name one Bt gene that encodes protein in corn plants to control corn borers.

(iv)

OR A gene was identified in a fungus by a research worker in a lab which was considered to be of a great importance in the field of agriculture. As a student of biotechnology, write the steps you would suggest to (i) Isolate this gene of interest from the fungus and (ii) amplify this gene for further experimentation and research.

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CBSE Class 12 Biology past-paper question from the 2022board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.