B3h - cloning

Question 1

Describe some possible uses of cloning(3)

Answer 1

Mass-producing animals with desired characteristics

Produce animals that have been genetically engineered to provide human products(e.g. create replacement organs that are suitable for transplant into humans)

Producing human embryos to supply stem cells for therapy

Question 2

Describe some ethical dilemmas concerning human cloning(3)

Answer 2

It is wrong to clone people as they will not be true individuals

Clone may be psychologically damaged by the knowledge that it is just a clone of another person

Clones of other mammals have been unhealthy and die prematurely - human clones might too

Question 3

How was Dolly the sheep produced(2)

Answer 3

By a process called nuclear transfer

-removing the nucleus from a body cell and placing it into an egg cell that has had its nucleus removed

Question 4

Describe the cloning technique used to produce Dolly(5)

Answer 4

1. Nucleus removed from egg cell
2. Egg cell nucleus replaced with the nucleus from a body cell(for Dolly it was from an udder cell)
3. Egg cell is given an electric shock to make it divide
4. Embryo implanted into a surrogate mother sheep
5. Embryo grows into a clone of the sheep from which the body cell came

Question 5

Describe the risks of using cloning technology(2)

Answer 5

Cloning is relatively new and might have consequences that we’re not aware of

Cloned animals are not as healthy as normal ones

Question 6

What is the possible implication of using genetically modified animals to supply replacement organs for humans

Answer 6

May lead to diseases being passed on from animals to humans

Question 7

Describe the advantages associated with the commercial use of cloned plants(2)

Answer 7

Growers can be sure of the characteristics of each plant since all plants will be genetically identical

It is possible to mass produce plants that may be difficult to grow from seeds

Question 8

Describe the disadvantages associated with the commercial use of cloned plants(2)

Answer 8

If the plant is susceptible to disease or to change in environmental conditions then all plants will be affected

Lack of genetic variation

Question 9

Describe the process of cloning plants through tissue culture(3)

Answer 9

1. Plant is selected that has the desired characteristics
2. Large number of small pieces of tissue are cut from that plant(usually from root or shoot tips)
3. Small pieces of tissue are grown in test tubes or dishes containing a growth medium and at suitable conditions. This is done under aseptic(sterile) conditions to prevent growth of microbes that could harm the plants

Question 10

Why is cloning plants easier than cloning animals

Answer 10

Many plant cells retain the ability to differentiate, while animal cells usually lose this ability at an early stage