A scientist investigates two unsuccessful preparations for genetically modifying yeast cells. The same donor gene, type of vector and type of yeast cell are used in both preparations.
Each vector carries a marker that is detected only if the vector enters a yeast cell.
| Preparation | Required gene detected in vector before transfer | Vector marker detected inside yeast cells after transfer |
|---|---|---|
| R | no | yes |
| S | yes | no |
Which statement about the possible failed stages is supported by the results?
Joining can be ruled out in R because the marker was detected, and joining can be ruled out in S because the gene was detected in the vector.
Delivery can be ruled out in R because the marker was detected, and joining can be ruled out in S because the gene was detected in the vector.
Joining can be ruled out in R because the marker was detected, and delivery can be ruled out in S because the gene was detected in the vector.
Delivery can be ruled out in R because the marker was detected, and delivery can be ruled out in S because the gene was detected in the vector.
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.