B1.7.2 Reproduction

Question 1

What are the two forms of reproduction?

Answer 1

• sexual reproduction

- asexual reproduction

Question 2

What are the key features of asexual reproduction? (4 marks)

Answer 2

• no fusion of gametes
• only one individual is needed as the parent
• There is no mixing of genetic information
• no genetic variation in the offspring.
• produces clones (genetically identical individuals)

Question 3

What are the key features of sexual reproduction? (3 marks)

Answer 3

– involves the joining (fusion) of male and female gametes.

• involves the mixture of the genetic information from two parents
• leads to variety in the offspring

Question 4

Outline how gardeners can grow new identical plants quickly and cheaply

Answer 4

by taking cuttings from older plants.

Question 5

Outline how gardeners can mass produce new identical plants quickly.

Answer 5

by using tissue culture – using small groups of cells from part of a plant and growing them in sterile conditions

Question 6

Animals can be cloned using embryo transplants. What does this involve?

Answer 6

• splitting apart cells from a developing animal embryo before they become specialised
• transplanting the identical embryos into host mothers

Question 7

Outline how animals can be cloned using adult cell cloning.

4 marks

Answer 7

• the nucleus is removed from an unfertilised egg cell.
• the nucleus from an adult body cell is then inserted into the egg cell.
• An electric shock causes the egg cell to divide to form embryo cells containing the same genetic information as the adult skin cell.
• When the embryo has developed into a ball of cells, it is inserted into the womb of an adult female to continue its development.

Question 8

In genetic engineering what is used to ‘cut out’ genes from the chromosomes of humans and other organisms?

Answer 8

enzymes

Question 9

At what stage of development do genes need to be transferred to the cells of animals, plants or microorganisms?

Answer 9

• at an early stage in their development

- so that they develop with desired characteristics.

Question 10

What are genetically modified crops (GM crops)

Answer 10

Crops that have had their genes modified by adding genes from other organisms

Question 11

Suggest a use of genetically modified crops.

Answer 11

• producing crops that are resistant to insect attack or to herbicides.
• increasing crop yields.

Question 12

Suggest why people are concerns about GM crops.

Answer 12

• GM crops may affect populations of wild flowers and insects
• they are uncertain about the effects of eating GM crops on human health.