paper 1 specification 7

Question 1

Describe how genetic analysis has led to the suggestion of the three domains rather than the five kingdoms classification method

Answer 1

led scientists to rethink that members of the prokaryote kingdom were not closely related as first thought so this kingdom should be split into two groups called (archaea and bacteria). Woese suggested that all organisms should be divided into 3 groups

Question 2

what are the five kingdoms

Answer 2

animals
plants
fungi
prokaryotes-(single-celled organisms with no nucleus)
protists-(eukaryotic single-celled organisms)

Question 3

what are the three domains

Answer 3

archaea-found in extreme places and look similar to bacteria
bacteria-contains true bacteria like e.coli
eukarya-fungi,plants,animals and protists

Question 4

what is selective breeding

Answer 4

humans artificially select a plant/animal they’re going to breed so that the favoured genes remain in the population e.g crops with disease resistance

Question 5

what is the process for selective breeding

Answer 5

from your existing stock select the ones which have the favoured characteristics and breed them. Pick the best offspring and breed them together.Continue process over several generations and the desirable traits will get stronger

Question 6

how is selective breeding used in research

Answer 6

investigating alcoholism, rats have been bred with either a strong preference or a weak preference for alcohol so researchers can compare their differences in behaviour and cognitive function

Question 7

what are disadvantages of selective breeding

Answer 7

-reduces the gene pool and makes animals inbred which causes genetic defects and health problems
-ethically bad if animals are deliberately bred to have negative characteristics

Question 8

what is genetic engineering

Answer 8

modifying the genome of an organism to introduce desirable characteristics

Question 9

how does genetic engineering work

Answer 9

-cut open the plasmid DNA with a restriction enzyme which creates two sticky ends
-use the same restriction enzyme to cut open the gene that will have two base pairs.
-insert the gene into the plasmid DNA using a ligase enzyme. These will combine due to complementary base strands.
-insert the genetically modified plasmid DNA into the bacterial cell.

Question 10

Explain the advantages of genetic engineering to produce GM organisms including the modification of crop plants

Answer 10

-herbicide resistance to kill weeds
-increase crop yield/quality
-insect and pest resistance

Question 11

Explain the advantages and disadvantages of biological control

Answer 11

alternative to using pesticides. By releasing a natural predator into the crop-growing area, the number of pests can be reduced.
- can have consequences as the numbers of different organisms in the food web are changed.
-slow process

Question 12

Explain the disadvantages of genetic engineering to produce GM organisms including the modification of crop plants

Answer 12

-GMO crops could have harmful toxins and be consumed/allergic reactions
-unethical (give health problems to animal)
-transplanted genes may get into the environment.
-affect food chains