Unit 2 exam Flashcards

1
Q

what are genes

A

sequences of bases located on chromosomes that code for specific proteins (ATCG)

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2
Q

what do proteins from genes control

A

traits or characteristics of the organism

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3
Q

what are alleles

A

different forms of a particular gene

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4
Q

what is an example of a gene and a kind of allele

A

a gene would be eye colour and an allele of that gene is to have blue eyes

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5
Q

what is a genome

A

the complete set of genetic instructions for an organism (the total DNA)

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6
Q

how is a genome expressed

A

as the base sequence of the haploid set of chromosomes

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7
Q

how many chromosomes in a human

A

46, 23 pairs

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8
Q

how many autosomes in a human

A

44, 22 pairs

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8
Q

how many sex chromosomes in a human

A

2

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9
Q

Where do your 46 chromosomes come from

A

23 from father, 23 from mother

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10
Q

What are homologous chromosomes

A

matching pairs of chromosomes that have the same genes in the same places (same size)

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11
Q

what is the loci

A

the position of the gene on a chromosome

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12
Q

what is non-homologous

A

non-matching chromosomes

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13
Q

what are the 2 types of chromosomes

A

sex chromosomes and autosomes

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14
Q

how can autosomes be distinguished

A

the size, position of centromere and patterns of light and dark bands when stained

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15
Q

what is a karyotype

A

an image of chromosomes from a cell arranged in an organised manner

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16
Q

What do karyotypes do

A

allow us to see all the chromosomes and see if there is a wrong amount (diseases)

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17
Q

What are the 3 chromosome abnormalities

A

changes in the number of chromosomes, changes in a part of a chromosome, changed arrangements of chromosomes

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18
Q

what is trisomy

A

when an organism has an extra in a pair of chromosomes

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19
Q

what it monosomy

A

when an organism has one chromosome in a pair

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20
Q

what is a genotype

A

the combination of the particular alleles of a gene or genes that are present and active in a cell or in an organism

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21
Q

what is a homozygous genotype

A

when a particular gene comprises of two identical alleles, eg AA or aa

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22
Q

what is a heterozygous genotype

A

when a particular gene comprises of two different alleles, eg Aa

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23
Q

what is a phenotype

A

A phenotype is the observable or measurable characteristics of an organism. It is a product of the genotype and the environment.

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24
Q

what does codominance mean

A

when a heterozygote expresses both the dominant and the recessive trait of a gene in its phenotype

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24
Q

what does codominance normally entail

A

showing both phenotypes or both colours (not mixed)

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24
Q

what is incomplete dominance

A

appearance in a heterozygote of a trait that is between either of the trait’s homozygous phenotypes

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24
Q

what does incomplete dominance entail

A

merging of phenotypes or colours together

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25
Q

what are the factors of an autosomal dominant trait (3)

A

both sexes are featured, all affected people have at least one affected parent, cant reappear after having 2 non affected people

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26
Q

what are the factors of autosomal recessive traits (3)

A

trait can skip generations, parents that are not affected can have affected kids, if both parents are affected then all children will be as well,

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27
Q

what are some features of X-linked dominant traits (3)

A

a male with the trait only passes it to all daughters, it disappears if no one is affected, in large pedigrees more females are affected

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28
Q

what are some features of x-linked recessive traits (3)

A

affected mothers have affected sons, daughters of affected fathers are carriers, across a large pedigree more males will be affected

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29
Q

what is meiosis

A

sexual reproduction which halves the chromosome number to produce gametes

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30
Q

what are the stages of meiosis

A

PMAT i PMAT ii

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31
Q

what happens in interphase of meiosis

A

the DNA is replicated forming 4 chromosomes

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32
Q

what happens in prophase i

A

the chromosomes condense and nuclear envelope degrades, starting crossing over

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33
Q

what is crossing over (prophase i)

A

the chromosomes get tangled up and change/combine certain alleles that are random to cause genetic variation

34
Q

what happens in metaphase i

A

the new crossed over chromosomes line up down the equator of the cell

35
Q

what happens in anaphase i

A

the 4 chromosomes are separated by from each other when the spindle fibres pull them apart via the centromere

36
Q

what happens in telophase i

A

a nuclear envelope reforms around each new set of chromosomes (then cytokinesis occurs)

36
Q

what happens in prophase ii

A

chromosomes may re-condense again and the nuclear envelope breaks down again

36
Q

what happens in metaphase ii

A

the chromosomes line up down the equator of the cell

36
Q

what happens in anaphase ii

A

the chromosomes are spilt apart into single stranded ones by pulling from the spindle fibres on the sister chromatids

36
Q

what happens at telophase ii

A

a new envelope forms around each set of chromosomes

37
Q

at the end of meiosis how many haploid daughter cells are made

A

4 haploid daughter cells are made

38
Q

what are the causes of genetic variation

A

crossing over (prophase i) and independent assortment

39
Q

what is independent assortment

A

the formation of random chromosome combinations during meiosis that contributes towards producing variation

40
Q

what are 3 advantages of asexual reproduction?

A

can reproduce quickly, no energy used to find a mate, and able to colonise areas quickly

41
Q

what are 3 disadvantages of asexual reproduction?

A

if conditions change entire population can be lost, no genetic diversity, and pressure on availability of resources

42
Q

what are 3 advantages of sexual reproduction?

A

gives genetic diversity, variation means increased survival changes if conditions change, and variation between members of the same family due to crossing over and independent assortment during meiosis

43
Q

what are the 2 types of cloning techniques?

A

embryo splitting and somatic nuclear cell transfer

44
Q

what is embryo splitting?

A

process of separating the totipotent cells of a very early embryo, so that the resultant cells are each able to form a complete embryo

45
Q

what is somatic nuclear transfer?

A

a cloning technique that involves the nucleus of a somatic cell being transferred into the cytoplasm of an enucleated cell that is then stimulated to divide

46
Q

4

why is genetic diversity so important in a population?

A
  • increases species survival following environmental change
  • increases the number of individuals that can survive and reproduce
  • increases biodiversity in ecosystems
  • means natural selection can act, as there are many alleles to select from.
47
Q

what are abiotic factors?

A

Factors affecting a population that are environmental factors

48
Q

what are 3 examples of abiotic factors?

A

temperature, dessication (drying out) and weather

49
Q

what are biotic factors?

A

factors affecting a population that is a living factor

50
Q

What are 2 examples of biotic factors?

A

predators and diseases

51
Q

what are producers?

A

A members of an ecosystem community that bring energy from an external source into the ecosystem

52
Q

what are the main producers?

A

plants

53
Q

what is another name for producers?

A

autotrophic

54
Q

what is another name for consumers?

A

heterotrophs

55
Q

what are consumers?

A

organisms that obtain their energy and organic matter by eating or ingesting the organic matter of other organisms

56
Q

what are the 4 subcategories of consumers/heterotrophs?

A

herbivores, carnivores, omnivores and detritivores

57
Q

what are detritivores?

A

which eat decomposing organic matter such as rotting leaves, dung or decaying animal remains

58
Q

what are decomposers?

A

organisms, such as fungi, that can break down and absorb the organic matter of dead organisms or their products

58
Q

what is an example of detritivores?

A

earthworms

59
Q

what is the difference between decomposers and detritivores?

A

decomposers first break down the organic matter outside their bodies by releasing enzymes, and then they absorb some of the products, whereas detritivores don’t

60
Q

what are the levels of the food chain?

A
  1. energy
  2. producer
  3. primary consumer
  4. secondary consumer
  5. tertiary consumer
61
Q

what are trophic levels?

A

a different name for the levels of the food chain

62
Q

what are keystone species?

A

species whose presence in an ecosystem is essential for the maintenance of that ecosystem

63
Q

what is a behavioural adaptation?

A

Activities that an organism performs in response to internal and external stimuli

64
Q

what is a structural adaptation?

A

Physical features of an organism that enable them to survive in a given environment

65
Q

what is a physiological adaptation?

A

Internal and/or cellular features of an organism that enable them to survive in a given environment

66
Q

what is an intraspecific relationship?

A

Competition for resources between members of the same species

67
Q

what is an interspecific relationship?

A

competition for resources between members of different species

68
Q

what is an amensalism relationship?

A

one organism is inhibited or destroyed, the other is unaffected

69
Q

what is a predator-prey relationship?

A

one species kills and eats the other

70
Q

what is an herbivore-plant relationship?

A

an animal eats a plant

70
Q

what is a parasitism relationship?

A

an organism living on or within another organism to derive a benefit, whilst harming the host

71
Q

what is a mutualism relationship?

A

a beneficial relationship between two species

71
Q

what is a commensalism relationship?

A

one member gains a benefit and the other is unaffected

72
Q

what is symbiosis?

A

competition for resources in an ecosystem involving members of the same species

73
Q

what are the 8 types of relationships?

A

intraspecific, interspecific, amensalism, predator-prey, herbivore-plant, parasitism, mutualism and commensalism

74
Q

what are the 5 bioethical concepts?

A

integrity, justice, Beneficence, non-maleficence and respect

75
Q

what is integrity?

A

doing the right thing even if no one is looking

76
Q

what is justice?

A

equal distribution of benefits, rights, costs, and resources

77
Q

what is beneficence?

A

aiming to improve conditions for others through generosity and kindness

78
Q

what is non-maleficence?

A

avioding actions which led to harmful consequences

79
Q

what is respect?

A

considering the wellbeing, freedom, independence, values and beliefs of all people