Reproduction

Worked examples (12)extended set

• 1Describing asexual reproduction and sorting examples
• 2Gametes and variation in asexual reproduction (multiple choice)
• 3Identifying asexual reproduction in diagrams
• 4Plantlets on a Bryophyllum leaf
• 5A grass spreading across a sand dune
• 6Planting seed potatoes: asexual reproduction in crop production
• 7Binary fission: calculating bacterial numbers
• 8Duckweed practical: effect of temperature on asexual reproduction
• 9Budding in yeast: a sequence diagram
• 10Runners or seeds? Using data to compare two ways of reproducing
• 11Which one is not asexual? (multiple choice)
• 12Clones and a crop disease: interpreting a yield graph

Model answers (6)

• ✓Model answer — Paper 4 short-answer style
• ✓Model answer — Paper 4 short-answer style
• ✓Model answer — Paper 4 structured style
• ✓Model answer — Paper 4 (Extended) structured style
• ✓Model answer — Paper 4 (Extended) structured style
• ✓Model answer — Paper 4 (Extended) extended-response style

Worked examples (12)extended set

• 1Completing the description of sexual reproduction
• 2Which process is fertilisation? (multiple choice)
• 3Haploid or diploid? Four frog cells (multiple choice)
• 4Chromosome numbers through a chicken life cycle
• 5Stages of fertilisation: nuclei and chromosome sets
• 6A wheat breeder's view of sexual reproduction
• 7Variation in plants grown from seeds and from cuttings
• 8Mass spawning on a coral reef
• 9Measuring variation in seed mass: a practical
• 10Parasites in snails that reproduce sexually and asexually
• 11When a gamete is not haploid: chromosome calculations
• 12Water fleas that switch between asexual and sexual reproduction

Model answers (6)

• ✓Model answer — Paper 4 short-answer style
• ✓Model answer — Paper 4 short-answer style
• ✓Model answer — Paper 4 (Extended) structured style
• ✓Model answer — Paper 4 (Extended) structured style
• ✓Model answer — Paper 4 (Extended) structured style
• ✓Model answer — Paper 4 (Extended) extended-response style

Worked examples (12)extended set

• 1Labelling an insect-pollinated flower and stating functions
• 2Anthers and stigmas of a wind-pollinated flower
• 3Comparing pollen grains and calculating their actual size
• 4Self-pollination or cross-pollination? (multiple choice)
• 5Stigma and pollen of a wind-pollinated flower (multiple choice)
• 6The pollen tube and fertilisation in a carpel
• 7Suggesting why a plant self-pollinates
• 8Four tubes to test the conditions for germination
• 9Germination and the volume of water added
• 10Improving a drawing of a halved fruit and finding its magnification
• 11Effects of self- and cross-pollination on two plant populations
• 12Rate of pollen tube growth from a graph

Model answers (6)

• ✓Model answer — Paper 4 short-answer style
• ✓Model answer — Paper 4 short-answer style
• ✓Model answer — Paper 4 structured style
• ✓Model answer — Paper 4 (Extended) structured style
• ✓Model answer — Paper 4 (Extended) structured style
• ✓Model answer — Paper 4 (Extended) extended-response style

Worked examples (12)extended set

• 1Matching the parts of the male reproductive system to their functions
• 2The female reproductive system: parts, functions and where events happen
• 3Adaptive features of a sperm cell and its magnification
• 4Gametes and fertilisation (multiple choice)
• 5Comparing egg and sperm cells drawn to the same scale
• 6From fertilisation to implantation
• 7The fetus in the uterus: amniotic sac, amniotic fluid and umbilical cord
• 8Exchange of substances across the placenta
• 9How the mother's blood changes in the placenta (multiple choice)
• 10Blood data from the two vessels of the umbilical cord
• 11Smoking in pregnancy and birth mass
• 12Why the placenta is efficient, and why the bloods must not mix

Model answers (6)

• ✓Model answer — Paper 4 short-answer style
• ✓Model answer — Paper 4 short-answer style
• ✓Model answer — Paper 4 structured style
• ✓Model answer — Paper 4 (Extended) structured style
• ✓Model answer — Paper 4 (Extended) structured style
• ✓Model answer — Paper 4 (Extended) extended-response style

Worked examples (12)extended set

• 1Testosterone, oestrogen and secondary sexual characteristics
• 2Reading a graph of the uterus lining
• 3Identifying hormones from their graphs (multiple choice)
• 4Hormones and their roles in the cycle (multiple choice)
• 5Naming the hormones and where oestrogen and progesterone are made
• 6Why menstruation starts and a new egg develops
• 7Progesterone during pregnancy
• 8Mean cycle length and predicting ovulation
• 9Testosterone concentration during puberty
• 10A hormone that stops ovulation
• 11Low FSH and fertility treatment
• 12Detecting the LH surge with urine tests

Model answers (6)

• ✓Model answer — Paper 4 short-answer style
• ✓Model answer — Paper 4 short-answer style
• ✓Model answer — Paper 4 structured style
• ✓Model answer — Paper 4 (Extended) structured style
• ✓Model answer — Paper 4 (Extended) structured style
• ✓Model answer — Paper 4 (Extended) extended-response style

Worked examples (12)extended set

• 1What an STI is, and HIV and AIDS
• 2Ways HIV can and cannot be passed on (multiple choice)
• 3Four routes of HIV transmission
• 4Explaining how the spread of STIs is controlled
• 5New HIV diagnoses by route of transmission
• 6Effect of a control programme on new HIV infections
• 7Lymphocyte numbers after HIV infection
• 8Preventing HIV passing from mother to baby
• 9Statements about HIV (multiple choice)
• 10Why the number of people living with HIV can rise as new infections fall
• 11A model of a barrier method
• 12Evaluating an HIV education lesson

Model answers (6)

• ✓Model answer — Paper 4 short-answer style
• ✓Model answer — Paper 4 short-answer style
• ✓Model answer — Paper 4 structured style
• ✓Model answer — Paper 4 (Extended) structured style
• ✓Model answer — Paper 4 (Extended) structured style
• ✓Model answer — Paper 4 (Extended) extended-response style