Genetic engineeringIB MYP Biology: Subtopic test

1. 1
   Millions of people with diabetes need regular injections of insulin. Insulin used to be extracted from the pancreases of pigs and cattle. A biotechnology company in India now makes human insulin using genetically modified bacteria grown in large steel fermenters. The human insulin gene is cut out of human DNA and inserted into a bacterial plasmid, which is then put into the bacteria.

   (a)

   Which type of enzyme is used to cut the human insulin gene out of human DNA?

   [1 mark]

   • ARestriction enzyme
   • BAmylase
   • CProtease
   • DLipase

   (b)

   What is the role of the plasmid in this process?

   [1 mark]

   • AIt cuts the gene out of the human DNA
   • BIt acts as a vector that carries the gene into the bacterial cell
   • CIt provides the energy for the bacteria to grow
   • DIt digests the insulin after it is made

   (c)

   Explain why bacteria are suitable organisms for making human insulin.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   Farmers in Burkina Faso compared two types of cotton in a field trial. Bt cotton contains a gene from the bacterium Bacillus thuringiensis, which makes a protein that is toxic to bollworm caterpillars. Conventional cotton does not contain this gene. Two plots of the same size were sown on the same day in the same field, with the same soil, water and fertiliser. At harvest, 100 plants were chosen at random from each plot and the number of damaged cotton bolls was counted. In the conventional plot there were 46 damaged bolls and in the Bt plot there were 7.

   (a)

   Which is the dependent variable in this field trial?

   [1 mark]

   • AThe type of cotton, Bt or conventional
   • BThe amount of fertiliser given to each plot
   • CThe day on which the plots were sown
   • DThe number of damaged cotton bolls out of 100 plants

   (b)

   Which conclusion is best supported by the results?

   [1 mark]

   • ABt cotton will give a higher yield on every farm
   • BBt toxin is harmless to all other insects
   • CBt cotton plants had less bollworm damage than conventional plants in this trial
   • DBt cotton is protected from all pests

   (c)

   Suggest two ways in which the farmers could improve the reliability of this trial.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   In parts of Asia and Africa, many children who eat mainly rice become short of vitamin A, which can cause blindness. Scientists produced 'golden rice' by adding genes from a plant and a bacterium to rice. The genes allow the rice grains to make beta-carotene, which the body converts to vitamin A. The grains are golden in colour.

   (a)

   Outline the main steps in producing golden rice.

   [3 marks]

   (b)

   Discuss two arguments for, and two arguments against, growing golden rice.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   Maize is the main food in a country in East Africa where droughts are becoming more frequent. A research institute wants to produce a drought-tolerant maize by transferring a gene from a desert plant that survives long periods without water. Supporters say it could protect the harvest. Critics worry that the GM maize could cross-breed with wild relatives and that farmers would have to buy new seed from a company every year.

   (a)

   Describe the steps the scientists would follow to produce the drought-tolerant maize.

   [6 marks]

   (b)

   Evaluate whether the country should allow farmers to grow the drought-tolerant GM maize.

   [6 marks]

   Total for question 4: 12 marks

End of questions