6.2 variation and gene technology

Question 1

variation, nature versus nurture

Answer 1

nature:
inherited. result of the combination of alleles inherited from parents.variation in phenotype arises as a result of mutations. many mutations don’t affect the phenotype becuase they do not change the structure of the protein that it is coded for, but some will affect phenotype
e.g. eye colour, blood t ype, dimples

nurture:
due to the conditions in which you developed (environment)
e.g. tattoos, scars, accent

combination:
weight, height, hair colour, skin colour

Question 2

selective bredding

Answer 2

the process by which humans breed plants and animals for particular genetic characteristics

1. select individuals with desired characteristics
   2, breed them
2. offspring show variation
3. choose the offspring with the desired characteristics
4. repeat this over many generations
5. until all offspring show the desired characteristics

can lead to inbreeding where some breeds are particularly prone to disease or inherited defects

Question 3

limitations of selective breeding

Answer 3

reduces genetic variation of the population
leads to inherited defects or an increased likelihood of developing certain diseases

Question 4

cloning plants

Answer 4

cuttings
tissue culture

Question 5

cuttings

Answer 5

cut a side branch from a parent plant below a node (meristem)
put in rooting hormone (auxin)
pot up in compost

Question 6

tissue culture

Answer 6

tissue samples are scraped from the parent plant
the cells are transferred to a sterile petri dish containing nutrients and auxins agar
hormones (e.g. auxins) are added to encourage plants to grow into small masses of tissue
tissue continues to grow and forms plantlets that can be transferred to potting trays and develop into plants

Question 7

cuttings vs tissue culture

Answer 7

cuttings
positives: much cheaper, doesn’t have to be in a sterile environment, more accessible (no specialist equipment needed, nayone can do it)
negatives: produces fewer plants, cuttings may damage the parent plant as large amount of tissue removed

tissue culture:
positives: produces large number of plants, more profitable
negatives: more expensive, needs to be in a sterile environment—difficult to achieve, needs specialist equipment

Question 8

embryo transplants

Answer 8

egg cells from the cow (with desired characteristics) are artificially fertilised using sperm cells taken from the bull (with desired characteristics) , which forms an embryo produced in vitro
the embryo is split apart many times into individual cells
the cells divide by mitosis to form many separate embryos that are genetically identical
the genetically identical embryos transferred into SURROGATE UTERUSES
the calves born are all genetically identical clone cows

Question 9

ads and dis of embryo cloning

Answer 9

advatages:
can produce many calves with desired characteristics
many calves produced rapidy

disadvantages:
ethical issues
low genetic variation so whole herd susceptible to same diseases

Question 10

adult cell cloning

Answer 10

1. remove a skin cell from the animal you wish to clone
2. remove an egg cell from a different animal and remoce its nucleus
3. place the nucleus from the skin cell into the empty egg
4. use an electric shock to stimulate mitosis
5. allow the cells to divide to form an embryo
6. insert the embryo into a surrogate uterus
7. the clone animal is born—genetically identical to the original animal that you take the skin cell from

Question 11

genome definition

Answer 11

all the dna that an organism possesses

Question 12

genetic engineering

Answer 12

process which involves modifying the genome of an organism by introducing a gene from another organism to give a desired characteristic

Question 13

genetic engineering how

Answer 13

1. desired gene cut out from donor genome
2. transferred/inserted into recipient genome
3. this is done using enzymes
4. all done at the EMBRYO STAGE

Question 14

genetically modifying bacteria to produce human insulin

Answer 14

a bacterial plasmid is cut open by a enzymes
enzymes are used to cut out the human insulin gene from donor genome
insert/join the human insulin gene into the plasmid
the genetically engineered plasmid is inserted into a bacterial cell
the bacteria reproduce, so the plasmids are copied as well
collect and purify the human insulin from the bacteria
so the insulin can then go on to be injected inot a patient

Question 15

uses of gm plants

Answer 15

increase nutrition in plants—purple tomato, golden rice
insecticides
can choose traits, predictable
weather/climate immmune plants
plants can be made immune to weed killers
terminator seeds
make certain plants immune to diseases
plants which fiz their own nitrogen
trees which can absorb more CO2
have the same amount of risk as non GMOs
plants that make their own pesticides

Question 16

GMOs +vs and -ves

Answer 16

+ves:
resistant to pests—>higher yields—>food security, and also less reliance on chemical pesticides
weather immune plants—>higher yields—>food security
provide additional nutrients, e.g. purple tomatos—>combats malnutrition
can make plants immune to diseases

-ves:
people are concerned about unknown long term health benefits/effects
negastive impact on wild plants and insects, e.g. interbreeding
GMOs could cross with non-GMOs (geneflow)