reproduction and inheritance Flashcards

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1
Q

what type of cells are human cells

A

diploid

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2
Q

what does diploid mean

A

2 comes of each chromosome arranged in pairs

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3
Q

how many chromosomes does a human cell have

A

46

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4
Q

where are chromosomes found

A

nucleus of the cell

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5
Q

what are chromosomes

A

long lengths of DNA coiled up

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6
Q

what is a gene

A

a short section of DNA

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7
Q

what is each separate gene

A

a chemical instruction that codes for a particular protein

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8
Q

what are different versions of the same gene called

A

alleles

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9
Q

what I the structure of DNA

A

double helix

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10
Q

four different bases

A

adenine
cytosine
guanine
thymine

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11
Q

what compliments A

A

T

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12
Q

what compliments C

A

G

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13
Q

what are the two strands of DNA held together by

A

bases

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14
Q

what are proteins made up of

A

chains of amino acids

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15
Q

how does each protein have a different function

A

the chains fold up to give each protein a different, specific shape, therefore the enzymes have different active sites

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16
Q

what is a codon

A

each amino acid is coded by a sequence of 3 bases in the gene

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17
Q

how Manu possible codons are there

A

64

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18
Q

how many amino acids are there

A

20

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19
Q

what stages are proteins made in

A

transcription
translation

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20
Q

where are proteins made

A

ribosomes

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21
Q

why can’t DNA move to the ribosome

A

it is found in the nucleus and is too big to move out

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22
Q

what is used to get info from the DNA to the ribosomes

A

messenger RNA (mRNA)

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23
Q

what is different about the bases in mRNA than in DNA

A

uses uracil (U) instead of thymine (T)

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24
Q

what enzyme joins together the base sequence to make mRNA

A

RNA polymerase

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25
Q

4 stages of transcription

A
  • RNA polymerase binds to a region of non-coding DNA in front of a gene
  • the 2 DNA strands unzip and the RNA polymerase moves along one of the strands in the DNA
  • It uses the coding DNA in the gene as a template to make the mRNA. Base pairing between the DNA and RNA ensures that mRNA is complimentary to the gene
  • Once made, the mRNA molecule moves out of the nucleus and joins with a ribosome in the cytoplasm
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26
Q

what is it called when the protein is assembled in protein synthesis

A

translation

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27
Q

4 stages of translation

A
  • amino acids are brought to the ribosome by another RNA molecule called tRNA
  • the order in which the amino acids are brought to the ribosome matches the order of the codons in mRNA
  • part of the tRNA’s structure is called an anticodon as it is complimentary to the codon for the amino acid. the pairing of the codon and anticodon makes sure that the amino acids are brought to the ribosome in the correct order
  • the amino acids are joined together by the ribosome making a protein
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28
Q

what type of reproduction involves mitosis

A

asexual reproduction

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29
Q

what is asexual reproduction

A

asexual reproduction involves only one parent. the offspring have identical genes to the parent so there is no variation between parent and offspring

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30
Q

what is mitosis

A

when a cell reproduces itself by splitting to form 2 cells with identical sets of chromosomes

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31
Q

what organisms reproduce asexually

A

bacteria and plants

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32
Q

process of mitosis

A
  • the DNA duplicates, forming X-shaped chromosomes, each arm a duplicate of the other
  • the chromosomes line up at the centre of the cell and cell fibres pull them apart, each arm of the chromosomes go to opposite ends
  • membranes form around each of the sets of chromosomes becoming nuclei of each cell
  • cytoplasm divides leaving 2 identical cells
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33
Q

what type of reproduction involves meiosis

A

sexual reproduction

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34
Q

what is sexual reproduction

A

the fusion of male and female gametes. Because there are 2 parents, the offspring contain a mixture of their parent’s genes

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35
Q

what is meiosis

A

meiosis produces 4 hapolosid cells whose chromosomes are not identical

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36
Q

process of division 1 meiosis

A
  • DNA duplicates and forms x-shaped chromosomes, each arm is an exact copy of the other
  • chromosomes line up I pairs in the centre of the cell, one chromosome in each pair is from the mother and one from the father
  • pairs are pulled apart, so each cell has only one copy of each chromosome
  • each new cell has a mixture of the mother’s and father’s
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37
Q

process of division 2 meiosis

A
  • chromosomes line up in the centre of the cell, the arms of the chromosomes are pulled apart
  • this results in 4 haploid gametes, genetically different
38
Q

male reproductive part of a plant

A

stamen

39
Q

female reproductive part of a plant

A

carpel

40
Q

what does the stamen consist of

A

anther and filament

41
Q

what does the carpel consist of

A

ovary, style and stigma

42
Q

what is the anther

A

contains pollen grains, which produce male gametes

43
Q

what is the filament

A

the stalk which supports the anther

44
Q

what is the stigma

A

the end part which pollen grains attach to

45
Q

what is the style

A

rod-like section that supports the stigma

46
Q

what is the ovary

A

contains the female gametes inside ovules

47
Q

what is pollination

A

the transfer of pollen from an anther to a stigma so that the male gametes can fertile the female gametes

48
Q

what is cross pollination

A

where pollen is transferred from the anther of one plant to the stigma of another

49
Q

what do plants that cross-pollinate rely on

A

insects or the wind

50
Q

how are some plants adapted for insect pollination

A
  • brightly coloured petals
  • scented flowers
  • big sticky pollen grains
  • sticky stigma
51
Q

how are some plants adapted for wind pollination

A
  • small dull petals
  • no strong scents
  • lots of small light pollen grains
  • long filaments that hang outside the flower
  • large feathery stigma
52
Q

what happens during plant fertilisation

A
  • pollen grains lands on stigma
  • pollen tube grows out of the pollen grain and down through the style to the ovary and into the ovule
  • nucleus from the male gamete moves down the tube to join with the female gamete in the ovule
  • nuclei fuse together to make a zygote, dividing by mitosis to form an embryo
53
Q

what is fertilisation

A

the fusion of gametes

54
Q

what is germination

A

when the seed starts to grow

55
Q

what conditions do a seed need to grow

A

water
oxygen
suitable temp for enzymes

56
Q

what are runners

A

fast-growing stems that grow out sideways just above the ground, they take root at various distances away for new plants to grow

57
Q

when is stage 1 of the menstrual cycle

A

days 1-4

58
Q

when is stage 2 of the menstrual cycle

A

days 4-14

59
Q

when is stage 3 of the menstrual cycle

A

day 14

60
Q

when is stage 4 of the menstrual cycle

A

days 14-28

61
Q

what happens in stage 1 of the menstrual cycle

A

uterus lining breaks down

62
Q

what happens in stage 2 of the menstrual cycle

A

uterus lining builds up again into a thick spongy layer ready for a fertilised egg

63
Q

what happens in stage 3 of the menstrual cycle

A

an egg develops and is released from the ovary, ovulation

64
Q

what happens in stage 4 of the menstrual cycle

A

wall is maintained for about 14 days, if no fertilised egg implants the cycle starts again

65
Q

4 hormones in menstrual cycle

A

FSH
oestrogen
LH
progesterone

66
Q

where is FSH produced

A

pituitary gland

67
Q

what does FSH do

A

causes an egg to mature in one of the ovaries
stimulates the ovaries to produce oestrogen

68
Q

where is oestrogen produced

A

ovaries

69
Q

what does oestrogen do

A

causes the lining of the uterus to grow
stimulates release of LH

70
Q

where is LH produced

A

pituitary gland

71
Q

what does LH do

A

stimulates release of an egg at day 14

72
Q

where is progesterone produced

A

ovaries

73
Q

what does progesterone do

A

maintains the lining of the uterus in the second half of the cycle

74
Q

what is the purpose of the placenta

A

lets blood of the embryo and mother get very close to allow the exchange of food, oxygen and waste

75
Q

what is the amnion membrane

A

surrounds the embryo and is full of amniotic fluid

76
Q

what is amniotic fluid

A

protects the embryo against knocks and bumps

77
Q

what are most characteristics controlled by

A

several genes interacting

78
Q

how many copies of each gene do you have

A

2

79
Q

what is an allele

A

different versions of the same gene

80
Q

what is a genotype

A

the allele that you have

81
Q

what is a phenotype

A

the characteristics the alleles produce

82
Q

what does homozygous mean

A

two of the same allele

83
Q

what does heterozygous mean

A

two different alleles

84
Q

what does co-dominant mean

A

neither allele is recessive so you show characteristics from both alleles

85
Q

how do you show genetic diagrams

A

Punnett square

86
Q

what is variation in animals due to

A

genes and environment

87
Q

what are plants characteristics due to

A
  • sunlight
  • moisture level
  • temp
  • mineral content
88
Q

what is the theory of evolution

A

life began as simple organisms from which more complex organisms evolved

89
Q

what does a mutation do

A

changes the sequence of the DNA bases in a gene, producing a genetic variant

90
Q

how do mutations affect protein

A

mutations change the code for amino acids that make proteins leading to changes in the protein it codes for

91
Q

what increases the chances of mutation

A

ionising radiation and mutagens