cloning

Question 1

what is micropropagation

Answer 1

a method of cloning plants by growing small pieces of plant tissue (called explants) in sterile conditions on a nutrient medium to produce genetically identical plants.

Question 2

steps of micropropagation

Answer 2

1- explants (small pieces of a plant) are taken from parent plant

2- they are sterilised to kill any microorganisms

3- explants are placed in sterile nutrient agar in a petri dish ( in vito= out of the body)

4- cells divide and form s callus (mass of identical cells)

5- callus is transferred to a new growth medium with plant growth hormones

6- plantlets planted in soil to grow into fully developed plants

Question 3

why use micropropagation (2)

Answer 3

produces many clones quickly

useful for rare, endangered species or genetically modified plants

Question 4

advantages of micropropagation (commercial) (5)

Answer 4

• can be grown all year round
• produces clones with desirable traits
• large numbers of plants produced cheaply
• useful in producing disease resitant plants
• helps conserve areas and endangered plants

Question 5

disadvantages of micropropagation (commercial) (3)

Answer 5

• requires sterile lad conditions and expert staff
• all clones genetically equal so vulnerable to same diseases and pests
• no genetic variation so no adaptation to changes

Question 6

embryo cloning

Answer 6

• best egg and sperm cell are artificially fertilised from the parents with desired characteristics
• single embryo formed
• embryo is split into smaller groups of cells BEFORE they specialise
• each cell group forms a genetically identical embryo
• these embryos are implanted into host mothers
• all offspring born are clones

Question 7

adult cell cloning

Answer 7

• nucleus is removed from an unfertilised egg cell
• nucleus from adult body cells is inserted into the egg
• a tiny electric shock stimulates the egg to divide by mitosis to form an embryo
• these embryo cells contain the same genetic information as adult cell
• when the embryo has developed into a ball of cells, it’s inserted into a host mother to continue the development until birth

Question 8

benefits of cloning (3)

Answer 8

• can be used to preserve endangered species and resurect extinct animals
• quick and cheap for commercial production and high quality products all year (plants)
• allows farmers to increase yields by using high quality livestock and plants

Question 9

risks of cloning (3)

Answer 9

• lack of genetic diversity
• some evidence that cloned animals may be less healthy than normal ones
• ethical concerns

Question 10

cloning to produce human proteins

Answer 10

• a transgenic animal has a foreign gene inserted into its DNA
• this gene causes animal to produce useful human protein (usually in its milk)
• once successful, animals os cloned, creating a herd which all produce the same protein
• PROCESS CALLED PHARMING

Question 11

example of cloning to produce human proteins

Answer 11

antibodies for cancer treatment