Selective breeding, cloning and genetic engineering

Question 1

What is selective breeding

Answer 1

When humans artificially select the plants or animals that are going t breed so that particular genes for particular desireable characteristics remain in the population

Question 2

Examples of desireable characteristics

Answer 2

Animals/crops that produce a higher yield
Crops with disease resistance
Plants with big or unusual flowers

Question 3

What are the 4 steps of selective breeding

Answer 3

1. From you existing stock, select the ones which have desireable characteristics
2. Breed them together
3. Select the best of the offspring and breed them together
4. Continue this process over several generations, and the desireable trait gets stronger and stronger. Eventually the offspring will have that desireable characteristic.

Question 4

One problem with selective breeding

Answer 4

Reduces the gene pool which can cause health problems as there is more chance of organisms inheriting harmful genetic defects.

Question 5

What is genetic engineering

Answer 5

the transfer of the gene pool responsible for a desireable characteristic from one organisms genome into another organism so that it also has the desireable characteristic.

Question 6

How can genetic engineering be done

Answer 6

by cutting out the desired gene and transferring it into the cells of another organism.

Question 7

What are the three steps of genetic engineering

Answer 7

1. A useful gene is isolated (cut) from one organism’s genome using enzymes and is inserted into a vector.
2. The vector is usually a virus or a bacterial plasmid (a small ring of DNA), depending on the type of organism that the gene is beig transferred to.
3. When the vector is introduced to the target organism, the useful gene is incerted into its cells.

Question 8

Issues surrounding genetic engineering

Answer 8

Long term effects are unknown and changing someones genes may accidentally create unplanned problems which could be passed on to future generations

Question 9

Benefits of GM crops

Answer 9

Increased yield
GM crops can be engineered to provide a food a nutrient that it is missing

Question 10

Concerns over GM crops

Answer 10

May have a knock on effect to other species

They could cause health issues in the future if ingested

Transplanted genes may get out into the environment (herbicide resistance gene may be picked up by weeds)

Question 11

What is cloning

Answer 11

Making a genetically identical copy of an organism

Question 12

What are the two plant cloning methods

Answer 12

Tissue culture
Cuttings

Question 13

What is tissue culture

Answer 13

A few plant cells are put in a growth medium with hormones and they grow into new genetically identical plants

Question 14

Positives of tissue culture

Answer 14

Can be done quickly in very little space any time

Question 15

What is tissue culture used for

Answer 15

To preserve rare plants that are hard to reproduce naturally and by plant nurseries to produce lots of stock quickly

Question 16

How is tissue culture done

Answer 16

Tissue removed from the tip of the plant

Tissue placed on a medium containing growth hormones

Hundreds of clones can be made

Question 17

What are cuttings

Answer 17

Gardeners can take cuttings from good parent plants and then plant them to produce genetically identical copies of the parent plant

Question 18

Advantages of cuttings

Answer 18

Cheap
Plants produced quickly
More simple than tissue culture

Question 19

4 steps of embryo transplantation

Answer 19

1. Sperm cells are taken from a prize bull and egg cells are taken from prize cow. Thee sperm are then used to artificially fertilise an egg cell.
2. The embryo that develops is then split many times (to form clones) before any cell is specialised
3. These cloned embryos are then implanted into other cows
4. They then grow into calves which will all be genetically identical to eachother

Question 20

What are the steps of adult cell cloning

Answer 20

Firstly, a nucleus is removed from an unfertilised ovum.
The nucleus from an adult body cell, such as a skin cell, is inserted into the enucleated ovum.
An electric shock stimilates the ovum to divide by mitosis to form an embryo.
These embryo cells contain the same genetic information as the adult skin cell.
When the embryo is developed into a ball of cells, its inserted into the womb of an adult female (surrogate) to continue its development.
This animal produced will be genetically idnetical to the animal from which a nucleus was taken but will have no relation to the ovum donor or the surrogate.

Question 21

Benefits of cloning

Answer 21

Gets you lots of ‘ideal offspring’ with desireable characteristics

Can be used to help preserve endangered species

Question 22

Concerns of cloning

Answer 22

Moral, religious, ethical beliefs
Reduced gene pool
Cloned animals may not be as healthy as normal ones.