Applications of recombinant DNA technologyAQA A-Level Biology: Flashcards

Exam questions on Applications of recombinant DNA technology

1. A pharmaceutical company produces human insulin by inserting the human insulin gene into plasmids, which are then taken up by bacteria grown in large fermenters. Before this technology, insulin for people with diabetes was extracted from the pancreases of pigs and cattle.
   Suggest two advantages of producing human insulin using recombinant bacteria instead of extracting it from pigs.2 marks
2. A seed company has produced soya plants containing a gene from a bacterium that makes them resistant to a broad-spectrum herbicide. Farmers can spray the herbicide over whole fields to kill weeds without harming the soya crop. Most of the farmers buying the seed run large commercial farms.
   Suggest two reasons why some environmental groups oppose the use of this herbicide-resistant soya.2 marks
3. A child is diagnosed with severe combined immunodeficiency (SCID), caused by a recessive allele that means the enzyme adenosine deaminase is not made, so white blood cells die. In a clinical trial, bone marrow stem cells are removed from each child, a functional allele is inserted into them using a viral vector, and the cells are returned to the child's blood. In the trial, 18 of 20 children recovered a working immune system within three years, but 2 children developed leukaemia because the vector inserted the allele next to a gene controlling cell division.
   Describe how gene therapy is used to treat a condition caused by a faulty recessive allele.3 marks