Everything from the 8 lessons of this topic on a few pages: the key idea of each lesson, the diagram to remember, the points to learn and the traps examiners set. Read it, cover it, test yourself.
Asexual reproduction is a process resulting in the production of genetically identical offspring from one parent. There are no gametes and no fertilisation, so the offspring (clones) have the same genes as the parent and as each other. Extended: it is fast and needs only one parent, but the lack of variation means a whole population can be wiped out by one change, such as a new disease.
Asexual offspring are not just similar to the parent: they are genetically identical. If you see variation between asexual offspring, it must be caused by the environment, not by their genes.
Do not just write "it is quicker" or "there is no variation". Say why it matters: for example, no variation means no individual is likely to be resistant, so the whole population or crop could be lost.
Sexual reproduction is a process involving the fusion of the nuclei of two gametes to form a zygote and the production of offspring that are genetically different from each other. Fertilisation is the fusion of the nuclei of gametes. Extended: the nuclei of gametes are haploid (one set of chromosomes) and the nucleus of a zygote is diploid (two sets).
Fertilisation is the fusion of the nuclei, not just the sperm touching or entering the egg. Write "the nucleus of the sperm fuses with the nucleus of the egg".
Variation is an advantage for the population, not a guarantee for each individual. Write that some individuals are likely to survive a change, so the species is less likely to die out.
Pollination is the transfer of pollen grains from an anther to a stigma. Insect-pollinated flowers have large, coloured, scented petals and nectar, with anthers and a sticky stigma inside the flower; wind-pollinated flowers have small or no petals, anthers hanging outside on long filaments and large feathery stigmas. Extended: self-pollination moves pollen to a stigma on the same plant; cross-pollination moves it to a flower on a different plant of the same species.
The stamen is the anther and filament together; the carpel is the stigma, style and ovary together. Do not label the whole carpel as the "ovary" or the anther as the "stamen".
A wind-pollinated flower has large feathery stigmas but small pollen grains. Students often swap these. A large surface catches pollen; small light grains travel far.
Two flowers on the same plant count as self-pollination, even though pollen has moved between flowers. Cross-pollination needs a different plant of the same species.
Fertilisation occurs when a pollen nucleus fuses with a nucleus in an ovule. Extended: after pollination a pollen tube grows out of the pollen grain, down through the style to an ovule, and enters it through the micropyle, carrying the pollen nucleus. Seeds need water, oxygen and a suitable temperature to germinate.
Pollination and fertilisation are different events. Pollination is pollen landing on the stigma; fertilisation happens later, inside the ovule, when the nuclei fuse. A pollen grain does not travel down the style: its tube grows down, carrying the nucleus.
Light is not one of the conditions needed for germination: the seed uses its food store, not photosynthesis. Do not add light, carbon dioxide or soil to your list.
Fertilisation is the fusion of the nuclei from a male gamete (sperm) and a female gamete (egg cell); in humans it happens in the oviduct. Sperm are small, numerous and swim using a flagellum; egg cells are large, few and cannot move by themselves. In early development the zygote forms an embryo, which is a ball of cells that implants into the lining of the uterus.
The sperm duct carries sperm; the urethra carries semen and urine out of the body. The oviduct (not the uterus) is where fertilisation normally happens. The bladder in the model is not part of the reproductive system.
Mitochondria give the sperm energy for swimming; they do not make it swim. The flagellum is what moves. Say "release energy by respiration", never "produce energy".
The embryo does not implant in the oviduct or the ovary. It implants in the lining of the uterus.
The placenta is attached to the wall of the uterus and the umbilical cord joins it to the fetus; the amniotic sac encloses the fetus in amniotic fluid, which protects it. Extended: in the placenta the blood of the mother and the blood of the fetus come very close but do not mix; dissolved nutrients and oxygen diffuse to the fetus and carbon dioxide and urea diffuse to the mother. Some pathogens and toxins can also cross the placenta and affect the fetus.
The umbilical cord carries the fetus's blood, not the mother's. The mother's blood stays in her own vessels in the placenta.
Do not write that the mother's blood flows into the fetus. Substances diffuse across the placenta; the two bloods never mix.
Testosterone (from the testes) and oestrogen (from the ovaries) cause the development of secondary sexual characteristics at puberty. In the menstrual cycle, of about 28 days, the uterus lining breaks down (menstruation), then repairs and thickens while an egg matures in a follicle; the egg is released at ovulation, about day 14, and the lining is kept thick ready for an embryo. Extended: FSH and LH come from the pituitary gland; oestrogen is made by the ovary (follicle), progesterone by the corpus luteum and, in pregnancy, by the placenta.
Secondary sexual characteristics develop at puberty. They are not the reproductive organs themselves, which are present from birth (primary sexual characteristics).
FSH and LH come from the pituitary gland, not the ovary. Oestrogen and progesterone come from the ovary (follicle and corpus luteum), and later in pregnancy from the placenta.
A sexually transmitted infection (STI) is an infection that is transmitted through sexual contact. The human immunodeficiency virus (HIV) is a pathogen that causes an STI, and HIV infection may lead to AIDS. HIV is passed on in body fluids: by unprotected sexual contact, sharing needles, infected blood and from mother to baby. The spread of STIs is controlled by using condoms, limiting sexual partners, testing and treatment, and education.
HIV is the virus; AIDS is the condition that may develop later when the immune system fails. Write "HIV infection may lead to AIDS", not "HIV is AIDS".
Antibiotics do not kill viruses, so they cannot cure HIV. Treatment with antiviral drugs controls HIV but does not remove it from the body.