A scientist is preparing a virus to act as a vector. The same restriction enzyme was used to cut a gene from donor DNA and to cut the viral DNA. No other enzyme has been added.
After the DNA molecules are mixed, the gene is held in place in the viral DNA, but the sugar-phosphate backbone is not continuous at either join.
Which of the following identifies what is holding the gene in place and what must be done to make the joins permanent?
Complementary base pairing between the sticky ends; add DNA ligase to seal the backbone.
The restriction enzyme bonding the DNA molecules together; add DNA ligase to seal the backbone.
The restriction enzyme bonding the DNA molecules together; add more restriction enzyme to seal the backbone.
Complementary base pairing between the sticky ends; add more restriction enzyme to seal the backbone.
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.