Biology

• Bacteria and plants can reproduce asexually to produce genetically identical individuals
• Sexual reproduction, involving the fusion of gametes introduces variety into animal and plant species.
• Asexual reproduction does not involve sex cells or fertilisation. Only one parent is required, unlike sexual reproduction which needs two parents.
• Pollination is the transfer of pollen from the anther to the stigma.
• During sexual intercourse sperm are transferred from the penis of the male into the vagina of the female. They then swim through the uterus to the oviduct and can fertilise an egg cell if one is present.
• Step 1 : Once every 28 days an egg cell is released from the ovary and moves into the oviduct (ovulation).
• Step two: During sexual intercourse sperm is ejaculated into the vagina. Sperm moves through the vagina, cervix, uterus and along the oviduct.
• Step three: It is in the oviduct that fertilisation takes place. The nucleus of one sperm fuses with the nucleus of an egg forming a zygote that contains genetic material from both parents. This random combination of parental gametes leads to variation within the species.
• In flowering plants, male and female reproductive structures can be found in the same individual plant. The organ of sexual reproduction is the flower.
• Male gametes are found in pollen grains and produced in the anthers of the flower.
• Female gametes are found in ovules and produced in the ovary of the flower.
• Sepals - Protect the unopened flower bud
• Petals - May be brightly coloured and scented to attract insects
• Stamens - The male parts of the flower consisting of the anther held up on the filament
• Anthers - Produce male gametes (in pollen grains)
• Stigma - The top of the female part of the flower which collects pollen grains
• Ovary - The bottom of the female part of the flower, produces the female gametes (in ovules)
• Nectary - May be present to produce sugary nectar to attract insects
• Reproduction - when organisms produce new living things
• Plants and animals reproduce to make new

  individuals of the same species.
• In asexual reproduction there is only one parent.

  The new individual is genetically identical to its

  parent.
• Most animals reproduce sexually.

  In sexual reproduction there are two parents.

  The parents have sex organs which produce sex

  cells or gametes.

  The offspring of sexual reproduction are

  genetically quite different to their parents.
• In males the sex cells are called sperm. Sperm are

  produced in sex organs called testes