Biology > B14: Variation/Evolution > Flashcards

B14: Variation/Evolution Flashcards

(20 cards)

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1
Q

what does the phenotype of an organism depend on?

A

GENOTYPE: - genes inherited /passed from parents
- genetic variation unless twins

ENVIRONMENT: - conditions organism grows and develops affects appearance

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2
Q

define

evolution

A

change in inherited characteristics of a populaton over time through natural selection which may form a new species

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3
Q

what is the THEORY OF EVOLUTION?

A

All species have evolved from simple life forms that first developed 3 bill yr ago

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4
Q

process of natural selection?

A
  • Mutation occurs –> variation
  • if mutation helps survival , organism will survive to breed
  • mutation passed to offspring
  • over generations, mutation will become more common in population
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5
Q

what is speciation?

A

one population of species beocme so different that they can no longer produce fertile offspring - new species

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6
Q

what is selective breeding?

A

when humans choose whihc organisms to breed in order to produce offspirng with desirable characteristics

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7
Q

process of selective breeding?

A
  • parenst with desirable charateristcis bred tgt
  • offspring wth these characteristics are bred
  • repeat
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8
Q

problems with selective breeding?

A

INBREEDING –> breeding with similar characteristics mean its likely they are related closely - REDUCED GENE POOL (as no. different alleles reduce)
- means less genetic variation /can be affected by disease
- can also mean more chance of geentic defects

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9
Q

what is genetic engineering?

A

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

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10
Q

process of genetic engineering of bacteria to produce insulin?

A
  • human insulin genes from chromosomes are ‘cut out’ using RESTRICTION ENZYMES leaving stickey ends
  • a virus or bacterial plasmid is cut using same RESTRICTION ENYZYME to also create sticky ends
  • loop/gene sticky end are joined together by DNA ligase enzymes
  • genetically engineered (recombinant) plasmid is inserted into a bacterial cell
  • when bacteria reproduce, plasmids are copied as well / spread (the will all express human insulin gene)
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11
Q

why are plants, bacteria and crop genetically modified?

A

PLANTS : for disease resistance/larger fruits
BACTERIA: produce useful substacnes fro humans (human insulin)
CROPS: - resistance to insects/herbicides –> high yield

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12
Q

how is genetic modification used in medecine ?

A
  • to cure inherited disorders
    called GENE THERAPY
  • involves transfering normal genes into patients so correct proteins are produced
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13
Q

benefits of genetic engineering?

A
  • useful in medecine to mass produce hormones
  • improves yields in agriculture (improves growth rates/ allows plants to grown in different environs/can make own pestcides)
  • crops with extra vitamins can be produced in areas, where it is difficult
  • more yields –> solve world hunger
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14
Q

risk of genetic engineering?

A
  • GM crops can effect plants therefore insects : - GM crops are infertile , so these genes can spread to plants, leading to infertility in other species
  • dont undertant effect of GM crops on human health
  • can lead to rise in designer babies
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15
Q

methods of plant cloning?

A

tissue culture: plant cells are taken and placed in growth medium with nutrients/hormones(auxin)
- grow into new plants that are clones (genetically identcial to parent)

cuttings: taken from plant with desirbale feature , and planted
- produce clones

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16
Q

process of embryo transplant?

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A
  • sperm /egg cells obtained from parents with desirbale features
  • in lab, fertilised to form embryo
  • embryo divides many times/ implanted into host mother
  • offsprig born as clone
17
Q

process of adult cell cloning?

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A
  • nucleus removed from unfertilised egg cell
  • nucleus removed from adult body cell / placed in egg cell
  • electric shock to stimulate division , egg cells divides to form embryo
  • embryo implanted into womb / offspiring is born as clone of adult body cell
18
Q

risks of cloning?

Study These Flashcards
A
  • gene pool is reduced - less likely to survive if disease arises
  • clones have low surivival rate/have genetci problems
  • may lead to human cloning
19
Q

variation?

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A

difference in characteristics in a population
- caused by combination of genes inherited and environmental exposure

20
Q

why are bacteria good organisms for genetic engineering?

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A
  • can be grown on large scale
  • less ethical objections
  • divide rapidly so express gene better
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