3.1 Understand the differences between sexual and asexual reproduction.
In sexual reproduction two parents create non-identical offspring, inheriting characteristics from both parents.
In asexual reproduction a single parent creates genetically identical offspring.
In asexual reproduction a single parent creates genetically identical offspring.
3.2 Understand that fertilisation involves the fusion of a male and female gamete to produce a zygote that undergoes cell division and develops into an embryo.
- Gametes are sex cells:
- The male one being sperm;
- The female one being an egg.
- When they join together it is know as fertilisation.
- At this point the fused gametes become a zygote.
- The zygote then divides repeatedly,
- At this stage it becomes an embryo.
Flowering Plants
3.3 Describe the structures of an insect-pollinated and a wind-pollinated flower and explain how each is adapted for pollination.
3.4 Understand that the growth of the pollen tube followed by fertilisation leads to seed and fruit formation.
- A pollen will travel down the stigma through a pollen tube, in to the ovule in the carpel.
- Here the pollen will fertilise the ovule, forming a zygote (the seed).
- The carpel (reproductive organ) becomes a fruit.
3.7 Understand that plants can reproduce asexually by natural methods (illustrated by runners) and by artificial methods (illustrated by cuttings).
Asexual reproduction only involves one parent, this can be achieved in two ways by plants:
- Runners (natural method):
- A second stem extends.
- When it reaches the ground, cells specialise into root cells and a new plant develops.
- A second stem extends.
- Cuttings(artificial method):
- A cut is put in to plant hormones, encouraging the ends to become roots.
- When placed in soil it will then create another plant.
Humans
3.8 Describe the structure and explain the function of the male and female reproductive systems.
Male reproductive system
Female reproductive system
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Sources: WebMD
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3.9 Understand the roles of oestrogen and progesterone in the menstrual cycle.
The menstrual cycle
Oestrogen and progesterone are both hormones which effect the menstrual cycle.
Oestrogen and progesterone are both hormones which effect the menstrual cycle.
- Oestrogen:
- Produced in the ovaries.
- Thickens the womb lining.
- Prompts the release of LH (Luteinizing hormone).
- Produced in the ovaries.
- Progesterone:
- Produced in the corpus-lutiem.
- Maintains the lining of the womb.
- Produced in the corpus-lutiem.
3.12 Understand the roles of oestrogen and testosterone in the development of secondary sexual characteristics.
Testosterone (males)
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Oestrogen (females)
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