Reproduction

  • Created by: Pablos
  • Created on: 13-04-18 12:04
What is sexual reporduction?
Involves the fusion of male and female gamates. Because there are TWO parents, the offspring contain a mixture of their genes.
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What is a gamate in humans?
Contains 23 chromosomes in humans -half the number of a normal cell.
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4 stages of sexual reproduction?
1. sperm/ova re produced 2. sperm is transferred to ovum 3. fertilastion occurs 4. zygote formed develops into a new individual
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Role of oestrogen and progesterone?
Oestrogen-develop femal secondary sexual characteristics Progesterone-develops lining of menstral cycle.
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Why is embryo developed in the placenta?
To allow embryo to obstain material such as oxygen and nutrients from mother's blood. It alos allows embyo to get ride of waste products such as urea and co2
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How is embryo protected by amniotic fluid?
During pregancy, a memebrane amnion encloses the developing embryo, Amnion secretes a fluid called amniotic fluid.
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Difference between sexual/asexual reproduction?
sexual-special sex cell(gamates), meiosis, fertilisation asexual- no specialised gamates, no fertilisation, one body divides by mitosis, roduces identical offspring
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Describe function of fertilisation?
Fusion of male and female gamates to produce a zygote that undergoes cell division and develops into an embryo
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Structures of insect-pollinted flower?
Stamens enclosed within flower so insect make contact, large petals to attract insects, larger sticky pollen grains to stick to insect bodies, bright petals to attract inscects, nectaries present, stigma enclosed within flower
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Structure of wind-pollinated flower?
stamens exposed so wind can easily blow pollen away, stigma exposed, stigma is feathery, small not bright petal, absent nectaries, smaller/smoother inflated grians of pollen grains.
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Fertilisation in plants?
The growth of the pollen tube followed by fertilisation lead to seed and fruit formation
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Conditons needed for seed germination?
Warm temperatures-so enzymes can act efficiently, water-for chemical reactions to occur in solution, oxygen-for respiration
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How geminating seeds utilise food reserves until seedling can carry out photosynthesis|?
Nutrients allow radicle and plumule to grow. Radicle grows down to soil which absorbs water and minerals ions. Plumule grows up towards light hwere photosyntesis occurs.
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How can plants reproduce asexually by natural methods?
Illustrated by runners and by artifical methods illustrated by cutting
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Other cards in this set

Card 2

Front

What is a gamate in humans?

Back

Contains 23 chromosomes in humans -half the number of a normal cell.

Card 3

Front

4 stages of sexual reproduction?

Back

Preview of the front of card 3

Card 4

Front

Role of oestrogen and progesterone?

Back

Preview of the front of card 4

Card 5

Front

Why is embryo developed in the placenta?

Back

Preview of the front of card 5
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