Reproduction Flashcards

1
Q

Definition of sexual reproduction

A

The joining of two sex cells or gametes during during fertilisation

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2
Q

Two characters of sexual reproduction

A
  • two parents needed

- offspring produced are genetically different to the parent

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3
Q

Two characteristics of asexual reproduction

A
  • One parent needed

- offspring produced are genetically identical to the parent (eg bacteria, production of spores by fungi)

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4
Q

Three advantages of sexual reproduction

A
  • introduces variation into a population
  • species can adapt to new environments
  • disease is less likely to affect all the individuals in a population
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5
Q

Two advantages of asexual reproduction

A
  • population can increase rapidly

- can exploit a suitable habitat quickly

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6
Q

Two disadvantages of sexual reproduction

A
  • time and energy needed to find a mate

- not possible for an isolated individual

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7
Q

Three disadvantages of asexual reproduction

A
  • does not lead to variation in a species
  • species may only be suited to one habitat
  • disease may affect all the individuals in a population
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8
Q

Name a natural method for the reproduction of plants

A

Runners

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9
Q

Name an artificial method for the reproduction of plants

A

Cuttings

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10
Q

Explain how runners can be used in the asexual reproduction of plants.

A
  • cells split off from the parent plant to grow a radicle (side branch) which forms plantlets
  • this forms a plant that is genetically identical to the parent plant via asexual reproduction (cloning)
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11
Q

Explain how cuttings can be used in the asexual reproduction of plants.

A
  • specific plant tissue is selected and sterilised
  • tissue sample is taken and grown in a petri dish containing sterile nutrient agar gel
  • the explant is treated with auxins to stimulate shoot + root development
  • once root and shoot are developed, the cloned plant is then transferred to soil
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12
Q

define fertilisation

A

the fusion of a male and female gamete to produce a zygote that undergoes cell division and develops into an embryo

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13
Q

Describe the process of fertilisation in plants

A
  1. Digestive enzymes are produced by the tip of the pollen tube, enabling it to grow through the style and ovary tissues and reach the ovule.
  2. The pollen grain enters the ovule through a small gap, the micropyle , to reach the egg cell (the female gamete).
  3. The male nucleus/gamete is then able to travel down the pollen tube into the ovule, so that it can fuse with the egg cell (fertilisation).
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14
Q

The plant zygote becomes…

A

The seed

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15
Q

Petals (wind pollinated)

A

Scentless, inconspicuous or absent (replaced by another structure)

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16
Q

Nectar and scent (wind pollinated)

A

None

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17
Q

Stamen (wind pollinated)

A

Long filaments so anthers hang outside flower when ripe.

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18
Q

Pollen (wind pollinated)

A

Grains with smooth surface to help float through the air. Produced in large quantities.

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19
Q

Stigma (wind pollinated)

A

Often feathery and hangs outside flower to increase chance of catching pollen in the air.

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20
Q

petals (insect pollinated)

A

Often scented and brightly coloured

21
Q

Nectar and scent (insect pollinated)

A

Insects feed on nectar (a sticky solution) and are attracted by scent.

22
Q

stamen (insect pollinated)

A

Enclosed in flower

23
Q

Pollen (insect pollinated)

A

Grains with surface features that help to stick to insects and stigma. Produced in small quantities

24
Q

Stigma (insect pollinated)

A

Enclosed in flower so that the insect brushes past it when entering flower. Top surface yellow to hold pollen.

25
Q

what is the plumule

A

the first emerging shoot

26
Q

what is the radicle

A

the first emerging root

27
Q

what is the cotyledon ?

A
  • contain food reserves that supply the young seedling with food when it starts to germinate
  • the cotyledons fulfil this role until the young plant grows its own leaves and becomes capable of making its own food via photosynthesis
28
Q

describe the order of hormones in the menstrual cycle

A

(day 1) FSH -> oestrogen -> LH -> progesterone (day 28)

29
Q

where is FSH released?

A

in the pituitary gland

30
Q

what are the roles of FSH in the menstrual cycle?

A
  • causes an egg to develop in the ovaries

- stimulates production of oestrogen

31
Q

where is oestrogen released?

A

oestrogen is produced in the ovaries

32
Q

what are the roles of oestrogen in the menstrual cycle?

A
  • inhibits production of FSH
  • causes the uterus lining to thicken and grow
  • stimulates the production of LH
33
Q

where is LH released?

A

pituitary gland

34
Q

what are the roles of LH in the menstrual cycle?

A
  • inhibits the production of oestrogen
  • stimulates. the release of an egg at day 14 (ovulation)
  • stimulates the production of progesterone
35
Q

where is progesterone released?

A

ovaries

36
Q

what are the roles of progesterone in the menstrual cycle?

A
  • inhibits the production of LH

- maintains the lining of the uterus

37
Q

give 3 adaptations of the placenta

A
  • large SA
  • villi
  • rich supply of maternal blood vessels
38
Q

mother -> foetus

A

water, amino acids, fatty acids, glycerol, glucose, antibodies

39
Q

foetus -> mother

A

CO2, urea

40
Q

what is the role of the placenta?

A

allows substances to diffuse from the mother’s blood to the foetus and vice versa

41
Q

what is the role of the amniotic sac?

A

a membrane that forms around the embryo (made up of mostly foetal urine) which protects the embryo by cushioning impacts.

42
Q

describe 5 effects of testosterone on males?

A
  • voice breaks
  • testes start to produce sperm cells
  • hair grows on face and body
  • body becomes more muscular
  • sexual organs grow and develop
43
Q

describe 5 effects of oestrogen on females?

A
  • hips get wider
  • breasts develop
  • ovaries start to release egg cells and menstruation starts
  • sexual organs grow and develop
  • pubic hair grows
44
Q

state the functions of the testes

A
  • to produce sperm (the male gametes or sex cells)

- to make testosterone

44
Q

state the functions of the testes

A
  • to produce sperm

- to make testosterone

45
Q

state the function of the scrotum

A

the bag of skin that protects the testicles and keeps them at optimum temperature.

46
Q

give the function of the sperm ducts

A

carry sperm from the testicles to the seminal vesicles.

47
Q

give the function of the seminal vesicles

A

where sperm is mixed with semen.