B14

Question 1

What is variation?

Answer 1

Differences in the characteristics of individuals in a population

Question 2

What are the two causes of variation within a species?

Answer 2

Genetics

Enviroment

Question 3

What is evolution?

Answer 3

Gradual change in the inherited traits within a population over time

Question 4

Outline the thoery of natural selection?

Answer 4

1) genetic variation exists due to mutations
2) random mutation gives an organism a selective advantage
3) organism is better adapated to the enviroment
4) organism reproduces passing alleles onto the next generation

Question 5

How do two populations become different species?

Answer 5

When their phenotypes become different to the extent that they can no longer interbreed to produce fertile offspring

Question 6

What is selective breeding?

Answer 6

Process by which humans select organisms with desirbale charcateristics and breed them to produce offspring with simalir phenotypes

Question 7

Outline the main steps involved in selective vreeding

Answer 7

1) identify a desired characteristic
2) select parentd that show the desired traits and breed them
3) select offspring with the desired traits and breed them
4) process repeated until all offspring have the desired traits

Question 8

What is the mainadvantage of selective breeding?

Answer 8

Crops produce a higher yield of grain
Plants produce larger fruit
Animals with gentle nature.

Question 9

Outline the disadvantages of selective breeding?

Answer 9

Reduces the gene pool
Inbreeding resultd in genetic disorders
More likely to get harmful recessive alleles

Question 10

What is genetic engineering?

Answer 10

The modification of the genome of an organism by the insertion of a desired gene from another organism

Question 11

Examples of uses for GM plants?

Answer 11

Disease resistance

Produce larger fruits

Question 12

What is a use for genetically modified bacteria cells?

Answer 12

To produce human insulin to treat diabetes

Question 13

Describe the benefits of genetic engineering?

Answer 13

Increases crop yields
Useful in medicine
GM crops produce scarce resources

Question 14

Describe the risks of genetic engineering?

Answer 14

Negative environmental impacts

GM seeds are exspensive

Question 15

What are benefits of bt crops?

Answer 15

Increased crop yields

Bt toxin is specific to certain insects so is not harmful to other organisms

Question 16

Describe the process of genetic engineering?

Answer 16

1) DNA is cut at specific base sequences
2) enzymes are used to isolate the required gene, this gene is inserted into a vector(usually a bacterial plasmid or virus)
3) genes are transferred to the microorganisms Cells, they develop with the desired characteristics

Question 17

What is a vector?

Answer 17

Structure that delivers the desired gene into the recipient cells

Question 18

How can plants be cloned?

Answer 18

Taking plant culture

Tissue culture

Question 19

Describe how plants are grown using tissue culture?

Answer 19

1) select a plant that shows desired characteristics
2) cut multiple sample pieces from the meristem tissue
3) grow in a Petri dish containing growth medium

Question 20

What must be ensured when preparing tissue culture?

Answer 20

Ensure aseptic conditions to prevent contamination of organisms

Question 21

What does the growth hormone cobtain?

Answer 21

Nutrients and growth hormones

Question 22

What are the advantages of growing plants by tissue culture?

Answer 22

Fast and simple process
Requires little space
Enables the growth of many plant clones
Useful in preserving endangered plant species

Question 23

What are the disadvantages of growing plants by tissue culture?

Answer 23

Reduction in the gene pool
Plant clones have a low survival rate/life expectancy
Could increase the prescribe of harmful recessive alleles

Question 24

Detail the process of the plant cuttings method of plant cloning?

Answer 24

1) branch is cut off the parent plant
2) stem is planted
3) plant hormones are used to encourage new root development
4) plastic bag is used to cover the plant to keep it warm and moist
5) new roots and plants is formed

Question 25

Describe how adult cell cloning is performed?

Answer 25

1) the nucleus is removed from an unfertilised egg cell
2) the nucleus from an adult body cell is inserted into the egg cell
3) an electrical shock stimulates the egg cell to divid and it forms an embryo
4) the embryo contains the same genetic information as the adult body cell
5) the embryo is inserted into the uterus of an adult female to continue developing