selective breeding, cloning and genetic engineering (paper 2) TOPIC 6 Flashcards

1
Q

what else is selective breeding known as

A

artificial selection

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2
Q

define selective breeding

A

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

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3
Q

what does selective breeding ensure

A

that the genes for the chosen specific characteristic remain in the population

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4
Q

how long have humans been doing selective breeding

A

thousands of years

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5
Q

give some examples of desired characteristics

A
  • disease resistant crops
  • animals that produce more meat or milk
  • domestic animals with a gentle temperment
  • large or unusual flowers
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6
Q

what does selective breeding provide evidence for

A

evolution - shows how significant variation is in a (relatively) short period

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7
Q

describe the process of selective breeding

A
  • select parents with desirable characteristics
  • breed together
  • select offspring with desirable traits and breed again
  • over many generations
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8
Q

what are the three main problems with selective breeding

A
  • leads to reduction in the gene pool
  • inbreeding results in health problems
  • new diseases and defects can occur
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9
Q

explain how reduction of the gene pool is an issue from selective breeding

A
  • reduces the number of alleles in the population as chacateristics aren’t chosen
  • if conditions change and new characteristics are needed = problem from lack of variation, cannot cope with change
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10
Q

explain how inbreeding is an issue from selective breeding

A
  • results in very little variation in the population
  • can cause inherited defects to be passedd through to offspring
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11
Q

explain how new dieases and defects can occur from selective breeding

A
  • due to reduced genetic variation in a population
  • certain disadvantageous alleles are more common
  • organisms struggle to cope with diseases
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12
Q

what is meant by the term genetic engineering

A

the process involving modifying the genome of an organism by introducing a gene from another organism to give it a desried characteristc

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13
Q

how have plant crops been genetically engineered

A

to be resistant to diseases or to produce bigger better fruits

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14
Q

how have bacterial cells been genetically engineered

A

to produce useful substances such as human insulin to treat diabetes

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15
Q

what are organisms which have been given genes from other organisms called

A

transgenic

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16
Q

descirbe the process of genetic engineering

A
  • enzymes are used to isolate and ‘cut out’ the required gene from an organism
  • the gene is then inserted into a vector (plasmid or vector) using more enzymes
  • the vector is then used to insert the gene into the required cells
  • genes are transferred to the cell at an early stage of development
  • as the organism grows it developes with the new desired characteristics from the other organism
17
Q

give an example of genetic engineering

A
  • jellyfish gene to make crop glow when lacking water
  • GM plants are more resistant to herbicides
18
Q

what are the benefits of genetically modified organisms

A
  • nutritional value of crops are improved
  • increased crop yield helps global food security
  • crops have longer shelf life
  • crops are resistant to herbicides so fields can be treated
19
Q

what are the risks and issues with genetically modified organisms

A
  • new trains could cause health reactions
  • concerns in decreasing biodiversity
  • cross polination with non-GM crops = weeds
  • we do not know the long term effects
  • risk increase in allergies
  • infertility can spread to wild crops
20
Q

what is a clone

A

an individual that has been produced asexually and is genetically identical to the parent

21
Q

how do you clone plants

A

taking cuttings

22
Q

what is cutting in cloning plants

A

a form of asexual reproduction that has been carried out for hundreds of years

23
Q

what is a more modern version of cuttings from plants

A

tissue culture, it is more expensive but allows you to make thousands of new plants from one small tissue

24
Q

explain how plant cloning works (tissue culture)

A
  • use a mixture of plant hormones to make a small group of cells from the plant you want to clone
  • they then go on to produce a big mass of identical plant cells called a callus
  • then useing a different mixtur eof hormones or conditions, you can stimulate each of these cells to form a small new plant
  • guarenteing thousands of offspring with the desired characteristics
25
explain how plant cloning works (cuttings)
- small tissue sample taken from parent plant - tissue is grown in agar with nutrients and plant hormones - tiny identicle plantlets are formed - plantlets grow on
26
describe embryo cloning in animals
- give fertility hormones to a top-quality cow so she produces many eggs - fertilise these eggs using sperm from a really good bull - these zygotes are then split into several embryos - each embryo is transplanted into a host surrogate mothers - the calves are born and genetically identical to their parents (not the surrogate mother)
27
what is adult cell cloning
when a whole new whole animal is produced from the cells of one singular other adult animal
28
describe adult cell cloning
- the nucleus is removed from an unfertilised egg cell (enucleated) - at the same time the nucleus is taken from the adult body cell (eg skin cell) of the same species - the nucleus from the adult cell is inserted into the empty egg cell - the new egg cell is given a small electric shock to stimulate the dividing to form an embryo - when the embryo has developed it is inserted into the uterus of an adult female and continues to develope - when born it is genetically identical to the animal which nucleus was used
29
what is the name of the first large mammel to be adult cell cloned
dolly the sheep in 1996
30
what is the controversy around cloning - positive and negative
+ rare plants might be saved + allows mass production of genetically identicle offspring + can be quick - reduction in gene pool - morally wrong, organisms cannot consent - may be used to clone humans
31
give two examples how genetic engineering has been use to treat human diseases
- insulin has been developed to treat diabetes - engineer organisms to ave diseases so we learn how to treat them