chap 9- genetic changes in a population over time Flashcards

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1
Q

what is a gene

A

section of DNA that transmits genetic information

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2
Q

what is an allele

A

different forms of a gene

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3
Q

what is a genotype

A

the alleles present in an individual

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4
Q

what is a phenotype

A

observable physical traits

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5
Q

what are the types of variation

A

structural, biochemical, behavioural, developmental, physiological and geographic

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6
Q

what are allele frequencies

A

a measure of how common a particular allele is in the gene pool of a population

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7
Q

what are mutations

A

random/unpredictable changes in DNA. creates new alleles, genes and chromosomes

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8
Q

what are spontaneous mutations

A

copying errors during DNA replication

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9
Q

what are mutagens

A

factors that induce mutation

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10
Q

what are somatic mutations

A

occur in body cells and only affect that individual

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11
Q

what are germline mutations

A

are heritable because they affect gametes and can be passed on to offspring

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12
Q

what are point mutations

A

a mutation that alters, adds or removes a single nucleotide from a sequence of DNA or RNA is called a point mutation. typically affect a single gene

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13
Q

what are substitution mutations

A

a point mutation in which one nucleotide is replaced by another type of nucleotide.
can be silent mutations, missense mutations, or nonsense mutations

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14
Q

what are silent mutations

A

the new codon still codes for the same amino acid

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15
Q

what is a missense mutation

A

the new codon codes for a different amino acid

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16
Q

what are nonsense mutations

A

the new codon is a stop codon and shortens the amino acid chain (which may have severe affects)

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17
Q

what is a frameshift mutation

A

one nucleotide being either added or removed from a nucleotide sequence. alters every codon in that sequence from that point onwards

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18
Q

what are block mutations

A

mutations that affect large sections of a chromosome (multiple genes)

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19
Q

when do block mutations occur

A

in eukaryotic cells during meiosis

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20
Q

what are the types of block mutations

A

duplication, inversion, deletion, insertion, translocation

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21
Q

what is a duplication mutation

A

results in multiple repetitions of a sequence of DNA

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22
Q

what is an inversion mutation

A

mutations involve a broken section of the sequence rotating 180 degrees before reattaching.

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23
Q

what is a deletion mutation

A

involves the loss of large sequences of DNA from the chromosome

24
Q

what is an insertion mutation

A

involves a sequence breaking off one chromosome and attaching to another

25
Q

what is a translocation mutation

A

can involve two different chromosomes exchanging segments

26
Q

what is a chromosomal abnormality

A

when a mutation involves whole chromosomes or the number of chromosomes

27
Q

how is chromosomal abnormality detected

A

through karyotypes

28
Q

what are the two types of chromosomal abnormality

A

aneuploidy and polyploidy

29
Q

what is aneuploidy

A

abnormal number of a particular chromosome, either an extra chromosome or a missing chromosome

30
Q

how can aneuploidy be caused

A

non-disjunction during meiosis

31
Q

what is polyploidy

A

cells and organisms that have more than 2 copies of every chromosome

32
Q

what is natural selection

A

the influence of environmental pressures on allele frequencies of a population. occurs because of genetic variation between individuals.

33
Q

what is gene flow

A

the movement of alleles into and out of a gene pool

34
Q

how can gene flow occur

A

when different populations interbreed or individuals migrate between populations

35
Q

what is genetic drift

A

the change in allele frequencies in a population due to random events

36
Q

how can genetic drift occur

A

the bottleneck effect and the founder effect

37
Q

what is the bottleneck effect

A

when an event (often a natural disaster) significantly reduces the size of a population and thus its genetic diversity

38
Q

what is the founder effect

A

when a small group of individuals breaks away from the main population and colonises a new habitat

39
Q

what is selective breeding

A

where individuals with desirable traits are deliberately interbred to produce offspring with those desired traits

40
Q

why do people selectively breed plants

A

to produce higher quality food

41
Q

why do people selectively breed animals

A

meat, milk quality. wool quantity/quality etc

42
Q

how is selective breeding done

A

1- determine desired trait
2- interbreed parents who show desired trait
3- select the offspring with the best form of the trait and interbreed these offspring
4- continue this process until the population reliably reproduces the desired trait

43
Q

what are advantages of selective breeding

A

allows for higher quality products for consumption/use
increase yields from plants/animals
produce fitter/stronger animals, more viable plants

44
Q

what are disadvantages of selective breeding

A

can reduce resistance to environmental change
can increase genetic abnormalities
can lower genetic diversity

45
Q

what is antibiotic resistance

A

when bacteria become resistant to antibiotic

46
Q

what are antibiotics

A

chemicals that are toxic to bacteria

47
Q

what is a superbug

A

when a bacterium becomes resistant to 2 or mor antibiotics

48
Q

why are bacteria ideally suited to develop antibiotic resistance

A

they are vastly numerous, small in size, have compact genomes, reproduce rapidly

49
Q

how do new genes for antibiotic resistance arise

A

by a combination of gene duplication and mutation

50
Q

what are some strategies to reduce antibiotic resistance

A

prohibiting sale of over the counter antibiotics
delaying prescription of antibiotics
enforcing tighter management/use of antibiotics
discovering/developing new antibiotics

51
Q

what is antigen drift

A

change in the surface of a virus due to gradual accumulation of mutations in the genes that code for virus surface proteins. mutations are small and new antigen is only slightly different

52
Q

what is antigen shift

A

a sudden change in the antigen of a virus resulting in the combination of genetic material from 2 or more strains/subtypes of the virus. antigens will be substantially different

53
Q

how can antigen shift occur

A

when different host animals live close together, increasing the chances that the two different subtypes will meet in a common host

54
Q

what is the value of vaccination

A

prevents outbreaks of new virus strains/subtypes.

55
Q

how many subtypes of influenza can vaccinations normally protect against

A

can normally protect against 3-4 subtypes of influenza