1. How frequently do mutations occur ?
Answer
Mutations occur continuously.
2. Name two methods of cloning plants.
Answer
Tissue culture and cuttings.
3. Describe the two causes of variation.
Answer
Variation is due to differences in inherited genes (genetic causes) and/or the environmental conditions in which an organism develops.
4. Define the term evolution.
Answer
Evolution is the change in the inherited characteristics of a population over time through a process of natural selection.
5. Humans have been selectively breeding plants and animals for particular characteristics for thousands of years. Give three useful characteristics that can be selected for.
Answer
Disease resistance in food crops, domestic dogs with a gentle nature, large or unusual flowers.
6. Genetic engineering involves modifying the genome of an organism by introducing a gene from another organism to give a desired characteristic. Crops that have had their genes modified in this way are called genetically modified (GM) crops. Give some characteristics that have been introduced into GM plant crops.
Answer
To produce bigger and better fruits, increased yield, herbicide resistance, drought resistance, improved nutritional content, resistance to insect attack, and resistance to diseases.
7. Genetically modified crops can have many useful characteristics, but some people object to them. Describe two reasons why people may object to GM crops.
Answer
People may be concerned about the effects that GM crops might have on populations of wildflowers and insects. Some believe that the impact of eating GM crops on human health has not yet been fully explored.
8. Give some reasons why scientists might want to clone plants using tissue culture.
Answer
To preserve rare plant species or protect endangered species from extinction.
9. Adult cell cloning has been used to clone an endangered wild sheep called a mouflon. The figure below shows how the scientists cloned a mouflon. Describe how adult cell cloning could be used to clone a mouflon.
Answer
Take an unfertilised egg cell from the sheep and remove its nucleus. Take a body cell from the mouflon and remove its nucleus, then put the body cell nucleus into the empty egg cell. Give the egg cell an electric shock so the egg cell starts to divide and form an embryo. Put the embryo in the uterus of an adult female sheep (the surrogate mother).