Scientists use a virus vector to transfer a required gene into cultured animal cells.
| Attempt | Required gene joined to vector before transfer | Suitable regulatory DNA sequence present | Vector genetic material detected inside recipient cells | Required protein detected |
|---|---|---|---|---|
| R | yes | yes | no | no |
| S | yes | no | yes | no |
Explain why the required protein was not produced in attempts R and S.
The scientists repeat attempt S with a suitable regulatory DNA sequence. Only some of the cultured cells take up the vector genetic material.
Explain why the scientists identify the cells that contain the vector before growing cells on a large scale.
100 exam-style questions on Edexcel GCSE Biology 4.3 Selective breeding and genetic modification, covering 4.3.1 Selective breeding and its impact, 4.3.2 Tissue culture, 4.3.3 Genetic engineering overview, 4.3.4 Main stages of genetic engineering, 4.3.5 Advantages and disadvantages of GM organisms, 4.3.6 Agricultural solutions for a growing population, and 4.3.7 Evaluating genetic engineering and breeding. Each one has a worked solution and a mark scheme showing where the marks go.