Genetic Fingerprinting and Recombinant DNA Technology: Insulin and GM Crops

Overview

Recall questions on Insulin and GM Crops.

What you need to know

Answer each one before you reveal it.

Questions from this subtopic

Each one with the model answer underneath.

1. 1

   How can the bacteria that have taken up the plasmid be identified?

   Model answer

   The plasmid also carries a marker gene such as one for antibiotic resistance, so the culture is grown on a medium containing that antibiotic and only the transformed cells survive.

2. 2

   Why are the transformed bacteria then grown in a large fermenter?

   Model answer

   They divide rapidly to give an enormous clone of identical cells, all expressing the inserted gene, so the useful protein is produced in commercial quantities.

3. 3

   Give two advantages of insulin produced by genetically modified bacteria over insulin extracted from pigs and cattle.

   Model answer

   It is identical to human insulin, so it works better and is far less likely to provoke an allergic response, and it avoids using animal products, which is important to some patients on religious or ethical grounds.

4. 4

   Why is a supply of bacterial insulin more secure than one taken from slaughterhouse pancreases?

   Model answer

   Production can be scaled up in fermenters to meet rising demand and carries no risk of transferring an animal disease, whereas extraction depends on the number of animals slaughtered.

5. 5

   Why might a gene for disease resistance be inserted into a tomato plant?

   Model answer

   The crop is then damaged less by the pathogen, so yields rise and less pesticide has to be sprayed.

6. 6

   Genetically modified soya has been given tolerance to a herbicide. What is the benefit to the grower?

   Model answer

   The whole field can be sprayed to kill the weeds competing with the crop, without harming the soya itself.

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