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Biology Mine > reproduction and inheritance > Flashcards

reproduction and inheritance Flashcards

1
Q

where is all genetic material in the form of chromosomes

A

in the nucleus

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2
Q

what is a chromosome

A

long length of DNA coiled up

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3
Q

what is a gene

A

a short section of DNA

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4
Q

what does diploid mean and where are they found

A

have two copies of each chromosome and are arranged in pairs. these occur in human cells

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5
Q

how many chromosomes does a healthy human have

A

46 23 pairs

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6
Q

what are genes

A

chemical instructions

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7
Q

what is DNA

A

a long list of instructions on how to put an organism together and make it work

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8
Q

why are proteins important

A

control most processes in the body

they determine inherited characteristics e.g eye colour, blood type

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9
Q

what controls the production of proteins

A

genes (so they also control are inherited characteristics)

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10
Q

what does DNA appear as

A

a double helix (two spirals)

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11
Q

what hold two strands together in DNA

A

Bases

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12
Q

what are the four different bases

A

(A) adenine (C) cytosine (G) guanine (T) thymine

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13
Q

what are the two pairs of bases

A

A-T C-G
adenine + thymine
cytosine + guanine

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14
Q

why do genes always come in pairs

A

one is from farther and the other is from the mother

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15
Q

what are the two ways an organism can reproduce

A

sexually and asexual

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16
Q

definition of asexual reproduction

A

involves only one parent. The offspring have identical genes to the parent - so there’s no variation between parent and offspring.

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17
Q

name a form of asexual reproduction

A

mitosis (involves two cells dividing in two and forming an extra cell genetically the same to the other)

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18
Q

give a definition of mitosis

A

is when a cell reproduces itself by splitting to form two cells with identical sets of chromosones

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19
Q

list the steps of mitosis

A

in a cell that’s not dividing, the DNA is all spread out in long strings
1. if the cell gets a signal to divide, it needs to duplicate its DNA so there’s only one copy for each new cell.
The DNA forms X-shaped chromosoms. Each ‘arm’ of the chromosome is an exact duplicate of the other.

  1. The chromosomes then line up at the centre of the cell and cell fibres pall them apath
  2. membranes form aound each of the sets of chromosomes these become nuceli of the new cells
  3. lastly cytoplasm divides
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20
Q

how is mitosis used in the human body

A

for growth and repair

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21
Q

give a definition of sexual reproduction

A

sexual reproduction involves the fusion of the male and female gametes.
Because there are TWO parents, the offspring contain a mixture of their parents’ genes

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22
Q

what is the difference between meiosis and mitosis

A

Meiosis produces four haploid cells whose chromosomes are NOT identical

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23
Q

list the steps of meiosis

A

step 1
same as start of mitosis

step 2
chromosomes in both cells line up and then split again and left with 4 haploid cells

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24
Q

what is the name of the male reproductive part of the plant

A

staMEN

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25
Q

what is the name of the female reproductive part of the plant

A

carpel

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26
Q

what does the stamen consist of

A

anther and filament

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27
Q

what does the carpel consist of

A

ovary, style and stigma

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28
Q

what does the anther contain

A

pollen (male gamete)

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29
Q

what is the filament

A

is the stalk that supports the anther

30
Q

what is the stigma

A

the end bit that the pollen grains attach to

31
Q

what is the style

A

rod like section that supports the stigma

32
Q

what is the ovary

A

contains the female gamete inside ovules

33
Q

what is pollination

A

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

34
Q

what is cross pollination

A

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

plants which cross pollinated rely on wind and insects

35
Q

how are some plants adapted for insect pollination

A

brightly coloured petals
scented flowers
big sticky pollen grains
stigma is sticky so pollen can be picked up from insects

36
Q

how are some plants adapted for wind pollination

A 
small dull petals 
no strong scent
lots of pollen grains 
long filaments that hang from the anther 
large feathery stigma to catch pollen
37
Q

what is fertilisation

A

the fusion of gametes

38
Q

list the stages of fertilisation in a plant

A
  1. pollen grains land on the stigma
  2. pollen tube grows out of the pollen grain and down through the style to the ovary and into the ovule
  3. nucleus from the male gamete moves down the tube to join with a female gamete in the ovule
  4. each fertilised female gamete forms a seed. The ovary develop into a fruit around the seed.
39
Q

what is germination

A

when a seed starts to grow

40
Q

what 3 thing does a plant need for germination

A
  1. Water - to activate the enzymes that break down the food reserves in the seed
  2. oxygen - for respiration, which provides the energy for growth
  3. a suitabl temperature - for enzymes inside the seed to work
41
Q

what does a developed seed contain

A

an embryo and a store of food reserves

42
Q

name two methods of natural asexual reproduction in plants

A
  1. runners

2. tubers

43
Q

give an example of runners and describe how they work

A

strawberry plants

  1. The parent strawberry plant sends out runners - fast growing stems that grow out sideways, just above the ground
  2. The runners take root at various points and new plants start to grow
  3. The new plants are clones of the parent strawberry plant, so there’s no genetic variation between them.
44
Q

name a method of artificial asexual reproduction in plants

A

cuttings

45
Q

how are cuttings taken from a plant

A
  1. cuttings are taken each with a new bud on
  2. The cuttings are kept in most conditions until they are ready to plat
  3. cloned plant produced
46
Q

learn both diagrams on page 57

A

learn 57

47
Q

what is the male hormone called

A

testosterone

48
Q

what do hormones do

A

promote sexual characteristics at puberty

49
Q

what does testosterone do

A

1) extra hair on face and body
2) muscles develop
3) Penis and testicles enlarge
4) sperm production
5) deepening voice

50
Q

what is the female hormone

A

oestrogen

51
Q

what are the effects of oestrogen

A

1) extra hair on underarms and pubic area
2) hips to widen
3) ovum releases and start of periods

52
Q

what happens at each stage in the menstrual cycle

A

stage 1) bleeding starts, the uterus lining breaks down for about for days
stage 2) the uterus lining builds up again
from day 4 to 14
stage 3) an ovum develop[s and is released from the ovary at day 14
stage 4) the wall is then maintained for about 14 days
days 14-28 if no fertilisation lining will begin to break down again

53
Q

what controls the menstrual cycle

A

oestrogen

progesterone

54
Q

what does oestrogen do (menstrual cycle)

A
  1. causes the lining of he uterus to thicken and grow

2. stimulates the release of an ovum at day 14

55
Q

what does progesterone do (menstrual cycle)

A

maintains the lining of the uterus. When the level of progesterone falls the lining breaks down

56
Q

what is the role of the placenta

A

to have blood pass very close to the mothers blood to exchange food, oxygen and waste

57
Q

what are Alleles

A

different versions of the same Gene

58
Q

what does homozygous mean

A

for a trait you have two alleles which are the same

59
Q

what is a genotype

A

the alleles you have

60
Q

what is your phenotype

A

characteristics the alleles produce

61
Q

what is codominance

A

when Neither allele is recessive so you show both characteristics, e.g blood

62
Q

do men have the xx chromosome or XY

A

Xy

63
Q

which parent has the y chromosome

A

dad

64
Q

What causes Genetic Variation is caused by

A

Genes

65
Q

name another factor which can cause variation in animals

A

The environment

66
Q

list 4 factors in a human which isn’t effected by the environment

A

1) Eye colour
2) Hair colour (in most humans)
3) Inherited disorders
4) blood group

67
Q

what is the theory of evolution

A

Life began as simple organisms from which more complex organisms evolved

68
Q

alist the steps of natural selection

A
  1. living things show variation
  2. the resources living things need to survive are limited individuals need
  3. some varieties of a species have a better chance of survival so have an increased chance of breeding
  4. next generation have a grater proportion of individuals in the next generation will have better alleles
  5. over many generations, the species becomes better and better able to survie
69
Q

what is a mutation

A

a rare random change in an organisms DNA that can be inherited

70
Q

how can a mutation be caused

A

when a chromosome doesn’t quite copy itself properly

71
Q

what can cause cancer

A

a mutation may start to multiply in a uncontrollable way

Biology Mine (7 decks)

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