Cloning

Question 1

What is a clone?

Answer 1

A genetically identical copy, derived from the same genetic material as an original organism, cell or gene.
Produced naturally or artificially.

Question 2

What are the two main processes of natural cloning in plants?

Answer 2

Asexual reproduction. (eukaryotic)

Vegetative propagation.

Question 3

How is asexual reproduction an example of natural cloning in plants?

Answer 3

Mitosis provides the mechanism by which cells are cloned.

Mitosis is responsible for asexual reproduction.

Question 4

What is vegetative propagation?

Answer 4

The production of structures in a plant that can grow into new individuals, which are clones of the parent.

Question 5

What are some examples of vegetative propagation?

Answer 5

Strawberry plants form runners.
Tubers and bulbs can grow new buds producing genetically identical plants.
Leaflets drop to the ground, producing new genetically identical plants.

Question 6

What is the name of the process of artificial cloning in plants?

Answer 6

Micropropagation by tissue culture.

Question 7

What is micropropagation?

Answer 7

The process of making large numbers of clones from a single parent plant using tissue culture techniques.

Question 8

In what situations is artificial cloning of plants useful? (5)

Answer 8

Propagating an infertile plant.
Propagating rare or endangered plants.
Propagating plants that are difficult to selectively breed.
Propagating plants that have been genetically modified.
If the plantlets need to be transported.

Question 9

What are the 4 stages in the micropropagation of a plant?

Answer 9

Explant
Callus
Plantlet
Young Plant

Question 10

What must be done to an explant to form a callus?

Answer 10

The explants are sterilised and grown on agar jelly containing nutrients and plant growth hormones, forming a totipotent callus.

Question 11

What is done to a callus to form plantlets?

Answer 11

The callus is subdivided and differentiated using plant growth regulators forming plantlets.

Question 12

What is done to a plantlet to form a young plant?

Answer 12

Plantlets are grown in sterile soil in a greenhouse.

Question 13

What are the advantages to the cloning of plants? (4)

Answer 13

Clones inherit good genes from the parent plant.
Allows an area to be populated very quickly.
Can occur if sexual reproduction not possible.
Plants can be produced external of environmental influences (seasons). (artificial)

Question 14

What are the disadvantages to the cloning of plants?

Answer 14

There is no genetic variation between clones, so cloning reduces the genetic diversity of the population.

• prevents the species from adapting via natural selection to a changing environment.
• leaves the population vulnerable to disease.

Question 15

What is the process of natural cloning of animals?

Answer 15

Identical twins (monozygotic twins).
This happens when the blastocyst naturally cleaves in two (embryo splitting).

Question 16

What are the two processes of artificial cloning of animals?

Answer 16

Somatic Cell Nuclear Transfer (SCNT)

Embryo splitting

Question 17

Describe the process of SCNT.

Answer 17

Egg cell (gamete) taken from donor and enucleated using a micropipette.
Nucleus taken from a somatic cell of the individual to be cloned and inserted into the enucleated egg cell.
The process of electrofusion allows this.
The young embryo completes its development in a surrogate mother.

Question 18

Why are electric shocks required in SCNT?

Answer 18

To insert the somatic nucleus into the enucleated egg cell and to cause the cell to begin development as if it had been fertilised.

Question 19

Describe the process of embryo splitting.

Answer 19

Sperm and eggs (gametes) taken from donor organisms with desirable genes.
In vitro fertilisation.
The embryo is split into several fragments.
The fragments are implanted into multiple surrogate mothers.

Question 20

What is the main difference between the result of embryo splitting as opposed to SCNT?

Answer 20

In embryo splitting, the offspring are not clones of a known organism, but clones of one another.

Question 21

What are the uses of embryo splitting?

Answer 21

Useful for research as different treatments can be compared without having to allow for differences in genotype.
Production of desirable animals for agriculture.
Allows embryos to be frozen and transported after the success of the offspring is asserted.

Question 22

What are the uses of SCNT?

Answer 22

Pharming.

• production of therapeutic human proteins.
• GMO’s to grow organisms for human transplant.
• production of animal models for research.

Question 23

What are some positives (ethical) of animal cloning?

Answer 23

Cloning can be useful in preventing the extinction of highly endangered species.
Cloning is very important in clinical trials for new therapies and pharmaceuticals, especially when using transgenic animals.
Cloning can be used to increase the yield of farmstock, accelerating the traditional process of selective breeding. -high value herds can be created quickly

Question 24

What are some negatives (ethical) of animal cloning?

Answer 24

SCNT is highly inefficient and the vast majority of cloned embryos fail to develop properly.
Most cloning procedures cause the suffering of animals.
There is evidence that clones have a higher mortality rate, even once fully developed.