4.6 Selective breeding and genetic engineering

Question 1

Selective breeding can also be called…

Answer 1

artificial selection

Question 2

Give examples of organisms that have been selectively bred.

Answer 2

1. Animals that produce more meat or milk.
2. Crops with disease resistance.
3. Dogs with a good, gentle temperament.
4. Decorative plants with big or unusual flowers.

Question 3

Describe the basic process of selective breeding.

Answer 3

1. Select individuals from your existing stock that have desirable characteristics.
2. Breed these individuals together.
3. Select the best offspring and breed them together.
4. Continue this process of several generations until the trait gets stronger and stronger.

Question 4

Another word for characteristics is…

Answer 4

traits

Question 5

What is meant by ‘yield’?

Answer 5

Amount of product made e.g. yield of wheat or meat produced.

Question 6

How many years have we been doing selective breeding for?

Answer 6

thousands

Question 7

What is meant by agriculture?

Answer 7

Farming

Question 8

What is the main draw back of selective breeding?

Answer 8

1. A reduction in the gene pool.

2. This could make a population vulnerable to disease.

Question 9

What is meant by the ‘gene pool’?

Answer 9

The number of alleles present in a species population.

Question 10

What is ‘inbreeding’?

Answer 10

Where closely related plants are bred.

Question 11

What is the negative consequence of inbreeding?

Answer 11

There is an increased risk of offspring developing health problems e.g. genetic diseases.

Question 12

What is genetic engineering?

Answer 12

Where genes responsible for a desirable characteristic are transferred from one organism to another.

Question 13

An organism that has received a gene from another organism is called a…

Answer 13

transgenic organism

Question 14

Describe the basic process of genetic engineering.

Answer 14

1. A useful gene is isolated from one organism’s genome enzymes.
2. The gene is inserted into a vector (a virus or bacterial plasmid).
3. The vector is introduced into the cells of the organism that you are modifying at an early stage of development (embryo).

Question 15

When should new genes be added to an organism during genetic engineering?

Answer 15

At an early stage of the organisms development e.g. when it is an embryo.

Question 16

How are genes cut from DNA?

Answer 16

Using enzymes

Question 17

The vectors that are used in genetic engineering can be…

Answer 17

viruses or bacteria

Question 18

List 3 examples of organisms that have been genetically engineered.

Answer 18

1. Bacteria produce human insulin to treat diabetes.
2. Genetically modified crops that produce large amounts of fruit, are disease and insect resistant.
3. Sheep that produce drugs in their milk.

Question 19

The idea of inserting working genes into people with genetic disorders is called…

Answer 19

gene therapy

Question 20

What are the pros of genetically modified (GM) crops?

Answer 20

1. Increased crop yields so more/cheaper food.
2. Crops can be engineered to produce more nutrients.
3. GM crops are already being grown without any problems.

Question 21

What are the cons of genetically modified (GM) crops?

Answer 21

1. GM crops may affect the number of wildflowers due to competition.
2. If fewer wild flowers, insect biodiversity could be reduced.
3. Herbicide resistant genes may ‘escape’ into other plants e.g. weeds, which would result in ‘super weeds’.
4. Some people think they might be unsafe and have bad effects on human health e.g. allergies.