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module 6 biology > patterns of inheritance > Flashcards

patterns of inheritance Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

what is a locus

A

specific position of a gene on a chromosome

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2
Q

what is co-dominance

A

pairs of alleles which are both expressed when present red flower + white flower = pink flower

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3
Q

what 2 processes cause genetic mutation?

A
  • random mutation
  • meiosis/sexual reproduction
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4
Q

what are physical agents of creating mutagens

A

ionising radiation e.g. X-rays

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5
Q

what is polyploidy

A

cell has extra set of chromosome

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6
Q

what is non-disjunction in cell division?

A

separation fails to occur causing both sister chromatids to be pulled to one side of the cell

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7
Q

environmental variation examples

A

hair length, accent

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8
Q

environmental and genetic variation examples

A

skin colour, height, weight

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9
Q

what is chlorosis and why is it an example of variation?

A

less chlorophyll = causing yellow leaves - it is an example of variation as the plant all have correct genes, chlorosis is affected by lack of light, and mineral deficiencies.

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10
Q

which form of data has a higher range of intermediates?

A

continuous

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11
Q

what do F2 ratios tell us?

A

if recessive allele is found in F2, both F1 parents must be heterozygous.

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12
Q

what are the steps of working out a Punnett square / dihybrid cross?

A
  1. find parent genotype
  2. use foil to work out gamete genotype
  3. set out 4 x 4 Punnett square
  4. combine possible gametes
  5. determine phenotype ratio
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13
Q

why are males described as hemizygous?

A

because they are haploid for X-linked gene.

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14
Q

features of haemophilia

A
  • unable to clot blot fast
  • gene found on non-homologous region of X-chromosome.
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15
Q

why can males never be a carrier?

A

if they inherit the faulty gene on chromosome X then they are bound to have the disease.

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16
Q

what is the relevance of “inactivation of X chromosomes in females?’

A

to avoid females expressing double number of genes from X chromosome, one is inactivated in every nucleus.
Happens randomly during embryonic development.

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17
Q

what is an autosome?

A

non sex chromosome

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18
Q

what is autosomal linkage?

A

two genes on the same non sex chromosome

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19
Q

which type of autosome can undergo independent assortment?

A

non linked because each one can move to one side where as linked can’t split

20
Q

what is meant by autosomal ‘linkage’

A

genes are on the same chromosome so likely to be inherited together and do not undergo independent assortment.

21
Q

what is recombinant gamete

A

combination of alleles

22
Q

hypostatic gene

A

the second gene loci that is masked by the epistatic gene

22
Q

what is epistasis?

A

the interaction of non-linked gene (independent assortment) loci where one masks the expression of the other gene.

23
Q

what is meant by complimentary gene action?

A

genes work together to code for two enzymes that work in succession e.g. catalysing sub sequential steps of the metabolic pathway.

24
Q

describe what is meant by recessive antagonistic epistasis

A

homozygous presence of a recessive allele at the first locus that prevents the expression of another allele at a second locus.

25
Q

describe what is meant by dominant antagonistic epistasis

A

if the epistatic allele is dominant, then having at least one copy of it will mask the expression of other gene = working antagonistically.

26
Q

what are the three types of selection

A
  • stabilising
  • directional
  • disruptive selection
26
Q

what ratio does recessive epistasis suggest?

A

9:3:4

27
Q

what ratio does dominant epistasis suggest?

A

12:3:1

28
Q

list the key words of natural selection

A

random mutation
migration
variation
selection pressures
selective advantage
beneficial allele
allele frequencies

29
Q

when does directional selection occur?

A

when there is a change in environment, and species with alleles form an extreme phenotype are more likely to survive + reproduction. Over many generations there is a gradual shift in the optimum value for trait.

30
Q

what is genetic drift

A

change in allele frequency in a population due to chance

30
Q

when does disruptive selection occur?

A

a type of natural selection where the extreme values are selected over the intermediate.

31
Q

what is a genetic bottle neck

A

when former population shrinks then new population rises again with advantageous alleles.

31
Q

how can gene pool be narrowed?

A
  • bottle neck
  • founder effect
32
Q

similarities between founder effect and genetic bottle neck

A
  • involve inbreeding
  • result in new population that carries alleles that are different from original group.
32
Q

what is the founder effect?

A

new population is established from a very small number of individuals who originate from a larger population.
This new population is likely to be less genetically varied.

33
Q

difference between founder effect and genetic bottle neck

A

bottle neck populations are killed, whereas founder effect occurs when populations are geographically separated.

34
Q

give three impacts of a small populations

A
  • loss of genetic diversity
  • inbreeding
  • rise in genetic disorders
35
Q

what factors affect the genetic diversity within a gene pool

A
  • population size
  • mutation rate
  • migration
  • natural selection
  • genetic drift
  • isolation of species (founder)
36
Q

what is allopatric speciation? (geographical)

A

formation of two different species from one original species due to geographical isolation.

37
Q

what is sympatric speciation? (reproductive)

A

formation of two different species from one original species, due to reproductive isolation, while the populations inhabit the same location.

38
Q

what is artificial selection?

A

selective breeding of organism involving humans choosing desired characteristics

39
Q

how can genetic diversity be increased in a population (by what process?)

A

hybrid vigour -> crossing over 2 varieties who are likely to reproduce heterozygous individuals, lowering the chance of recessive disorders.

40
Q

what are the ethical issues of artificial selection?

A
  • unfamiliar environment for species can lead to both psychological and physical distress
  • violation of animal rights
41
Q

what are the counter points to the unethical nature of artificial selection?

A
  • increases crop yield = boosts economy
  • greater breeding in plants and animals to allow their groups to survive which helps endangered species
  • quicker and efficient, get desirable characteristics e.g. size, milk yield.

module 6 biology (7 decks)

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