B15 Variation

Question 1

What is variation?

Answer 1

Differences in characteristics of individuals in a population

Question 2

What can cause variation?

Answer 2

Genetic causes
Environmental

Question 3

How do new phenotype variants occur?

Answer 3

Mutations

Question 4

What is selective breeding?

Answer 4

Breeding plants and animals for particular characteristics

Question 5

Describe the process of selective breeding

Answer 5

1. Choose parents with the desired characteristics
2.Breed them together
3.Choose offspring with desired traits and breed again
4. Continue over many generations until all offspring show this characteristic

Question 6

What are the consequences of inbreeding?

Answer 6

Inherited defects and disease

Question 7

What is genetic engineering?

Answer 7

Modifying the genome of an organism by introducing a gene from another organism to give a desired characteristic

Question 7

How have bacteria been genetically engineered?

Answer 7

To produce useful substances

e.g human insulin to treat diabetes

Question 7

How have plant crops been genetically engineered?

Answer 7

To be resistant to disease/herbicides/pesticides

To produce bigger fruits

To produce higher yields

Question 8

What are enzymes used for in genetic engineering?

Answer 8

To cut out the required gene

Question 9

What is used to transfer the required gene in to the new cell in genetic engineering?

Answer 9

Vectors
(such as bacterial plasmids or a virus)

Question 10

Describe the steps involved in adult cell cloning

Answer 10

1. Nucleus removed from unfertilised egg cell
2. Nucleus from adult body inserted in to egg cell
3. Electric shock stimulates egg cell to divide to form an embryo
4. Embryo develops and is inserted in to the womb

Question 11

What is tissue culture cloning?

Answer 11

Using small groups of cells from plants to grow new identical plants

Question 12

Why is tissue culture cloning of plants important?

Answer 12

to preserve rare species and for growing plants commercially in nurseries

Question 13

What is ‘cutting’ as a cloning method?

Answer 13

Simple method used by gardeners to produce many identical plants from a parent plant

Question 14

Describe cloning through using embryo transplants

Answer 14

Cells split apart from a developing animal embryo before they are specialised, then identical embryos are transplanted in to host mother

Question 15

What is selective breeding used for?
(examples)

Answer 15

Disease resistance in crops
Animals that produce more meat or milk
Larger or unusual flowers

Question 16

BENEFITS of cloning

Answer 16

Large number of identical offspring produced

Quick and economical

Desired traits guaranteed

Question 17

RISKS of Cloning

Answer 17

Limits variation and causes reduction in gene pool

May be more vulnerable to diseases and changes in the environment

Ethical considerations around cloning living organisms

Question 18

BENEFITS to Genetic engineering

Answer 18

Potential to overcome some inherited human diseases

Crops can be resistant to herbicides and make their own pesticides

Higher crop yields

Question 19

RISKS of Genetic engineering

Answer 19

Genes from GM plants may spread to other wildlife which could have a bad effect on ecosystems

Negative impact on population size of wild flowers and insects

Ethical concerns

We do not know the long term effect of eating GM crops

Question 20

What is a clone?

Answer 20

An individual that has been produced asexually and is genetically identical to its parent