Researchers are preparing a recombinant plasmid to transfer a drought-tolerance gene into lettuce cells.
A plasmid has already been cut open. Its sticky ends will pair only with sticky ends of type K.
The required gene occupies bases 800 to 1400 of a donor DNA molecule. Four fragments have been produced by cutting the donor DNA with restriction enzymes.
| Fragment | First base in fragment | Last base in fragment | Type of sticky end at both ends |
|---|---|---|---|
| W | 600 | 1600 | K |
| X | 900 | 1600 | K |
| Y | 600 | 1300 | K |
| Z | 600 | 1600 | L |
Which DNA fragment should be mixed with the opened plasmid?
Fragment Y
Fragment Z
Fragment W
Fragment X
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.