4.6.2.5 Cloning (biology only)

Question 1

Cloning:

Answer 1

creating genetically identical copies of an organism

Question 2

Tissue culture:

Answer 2

using small groups of cells from part of a plant to grow identical new plants

Question 3

How is tissue culture carried out?

Answer 3

• plant cells are taken
• they are placed in a growth medium with nutrients and hormones
• they grow into new plants and are clones as they are genetically identical to the parents

Question 4

What is tissue culture important for?

Answer 4

important for preserving rare plant species or commercially in nurseries

Question 5

Cuttings:

Answer 5

an older, but simple method used by gardeners to produce many identical new plants from a parent plant

Question 6

Embryo transplants:

Answer 6

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

Question 7

How do you carry out embryo transplants?

Answer 7

1. Sperm cells and egg cells from parents with desirable characteristics are obtained
2. In the lab, they are fertilised to form an embryo
3. The embryo divides many times and is split apart before cells have specialised to form 2 or more embryos
4. Embryos inserted into a host mothers
5. The offspring which is eventually born is genetically identical (with the desirable feature) as they have genetic information from the same mother and father

Question 8

How does adult cell cloning work?

Answer 8

1. The nucleus is removed from an unfertilised egg forming a denucleated egg cell
2. The nucleus is removed from an adult body cell e.g. skin cell and is inserted into the denucleated egg cell
3. An electric shock stimulates the egg to divide and form an embryo
4. These embryo cells contain the same genetic information as the adult skin cell
5. When the embryo has developed into a ball of cells, it is inserted into the womb of an adult female to continue its development
6. The offspring born is a clone of the adult body cell

Question 9

Benefits of cloning:

Answer 9

• produces lots of offspring with a specific desirable characteristic
• the study of clones could help research into embryo development
• can help extremely endangered species, or even bring back species that have become extinct

Question 10

Risks of cloning:

Answer 10

• the gene pool is reduced through producing clones - meaning it is less likely that the population will survive if a disease arises with low variation in the population
• clones have a low survival rate, and tend to have come genetic problems
• it may lead to human cloning