Scientists are developing pear trees whose fruit remains firm for longer after harvest. A gene from another plant species codes for a protein that delays fruit ripening. The donor species cannot breed with pear trees.
Scientists introduce the gene into pear cells and grow four trial trees from the treated cells. The trees are grown under the same conditions until they produce fruit.
| Trial tree | Inserted gene detected | Mean percentage of fruit still firm after 14 days (%) |
|---|---|---|
| A | no | 28 |
| B | yes | 82 |
| C | yes | 61 |
| D | no | 31 |
A fruit company wants to use small pieces of tissue from one trial tree to produce trees for a large orchard.
Explain which trial tree should be selected and how the two biological techniques used in this project allow many trees with the delayed-ripening characteristic to be produced.
Suggest why planting the whole orchard with trees produced only from tree B could result in severe losses if a new pathogen reached the orchard.
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.