A hospital is trialling a treatment in which immune cells are removed from a person with leukaemia. Fig. 1 shows how the cells are genetically changed so th...
Question 1 Report
A hospital is trialling a treatment in which immune cells are removed from a person with leukaemia. Fig. 1 shows how the cells are genetically changed so that they can recognise cancer cells. The altered immune cells are then grown outside the body before being returned to the person.
(a) Name the substance in a cell that carries the new gene. [2]
(b) Complete the sequence in Fig. 1 by stating what the virus vector delivers and what the altered immune cells can recognise after treatment. [3]
(c) Explain why mitosis is needed while the changed immune cells are grown in the laboratory. [4]
(d) Explain why the treatment should be tested in a small clinical trial before it is used for many people. [5]
Answer Details
(a) A new gene is carried in DNA, and DNA is arranged into chromosomes containing genes. Therefore credit is given for DNA and chromosome or gene. [2]
(b) The virus vector delivers the new gene or DNA into the immune cell. The gene causes production of a receptor or protein on the cell surface. The altered immune cell can therefore recognise cancer cells, including leukaemia cells. [3]
(c) Mitosis produces many cells from one successfully changed immune cell. Each daughter cell receives the same inserted gene. A large number of these immune cells is needed for treatment, and they can recognise and destroy cancer cells. [4]
(d) A small clinical trial checks whether the treatment is safe and identifies side effects. It also tests whether it is effective at reducing cancer cells and helps identify a suitable dose. Unexpected immune reactions can be monitored. Starting with few people limits the number exposed to possible risks. [5]
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