AQA GCSE Biology Paper 2 Revision Checklist

4.5 Homeostasis and response

16 sub-topics · 2 required practicals · 3 Higher-only.

• Homeostasis — Define homeostasis; give examples (blood glucose, body temperature, water balance).
• Negative feedback — Describe the components of a control system: receptor, coordination centre, effector.
• The nervous system — CNS vs peripheral; describe sensory, relay and motor neurones and synapses.
• Reflex actions — Describe the reflex arc and explain why it is rapid and automatic.
• Required practical: reaction timeRequired practical — Ruler-drop test; control variables, calculate mean and discuss the effect of caffeine.
• The brain (Biology only)Triple only — Label cerebrum, cerebellum, medulla; explain methods of investigation and difficulties of treatment.
• The eye (Biology only)Triple only — Structure and function; accommodation; long/short sight and corrections.
• Control of body temperature (Biology only)HigherTriple only — Vasodilation, vasoconstriction, sweating, shivering.
• The endocrine system — Label major glands; compare hormonal vs nervous communication.
• Control of blood glucose — Roles of insulin and (Higher) glucagon; type 1 vs type 2 diabetes.
• Hormones in reproduction — Roles of FSH, LH, oestrogen, progesterone; describe the menstrual cycle.
• Contraception — Compare hormonal and non-hormonal methods; evaluate ethical and reliability issues.
• Infertility treatments (Higher)Higher — Describe use of FSH/LH and the stages of IVF; discuss benefits and risks.
• Negative feedback — thyroxine and adrenaline (Higher)Higher
• Plant hormones (Biology only)Triple only — Auxins, gibberellins, ethene; phototropism and gravitropism in shoots and roots.
• Required practical: effect of light on seedlingsRequired practicalTriple only

4.6 Inheritance, variation and evolution

18 sub-topics · 2 Higher-only.

• Sexual vs asexual reproduction — Compare advantages and disadvantages; meiosis vs mitosis.
• Meiosis — Describe how meiosis produces four genetically different haploid gametes.
• DNA and the genome — Define gene, chromosome, genome; outline the Human Genome Project benefits.
• DNA structure (Higher)Higher — Describe the double helix, base-pairing (A–T, C–G) and complementary strands.
• Protein synthesis (Higher)Higher — Outline transcription and translation; explain effect of mutations.
• Genetic inheritance — Use Punnett squares for monohybrid crosses; define alleles, genotype, phenotype, homo/heterozygous.
• Inherited disorders — Polydactyly (dominant) and cystic fibrosis (recessive); evaluate embryonic screening.
• Sex determination — Use a Punnett square to show the inheritance of XX and XY.
• Variation — Distinguish genetic, environmental and combined causes of variation.
• Evolution by natural selection — Outline Darwin's theory; link mutation, selection pressure and reproductive success.
• Selective breeding — Process and examples; risks of inbreeding.
• Genetic engineering — Process; benefits and concerns; introduction to GM crops.
• Cloning (Biology only)Triple only — Tissue culture, cuttings, embryo transplants, adult cell cloning.
• Theory of evolution — Compare Darwin and Lamarck; describe the development of the modern theory.
• Speciation (Biology only)Triple only — Wallace and Darwin; isolation → genetic variation → speciation.
• Fossils and extinction — How fossils form; causes of extinction.
• Resistant bacteria — How MRSA arises and how to reduce antibiotic resistance.
• Classification — Linnaean system; binomial naming; three-domain system; evolutionary trees.

4.7 Ecology

13 sub-topics · 2 required practicals · 1 Higher-only.

• Communities — Define population, community, ecosystem, biotic and abiotic factors.
• Adaptations — Structural, behavioural and functional; examples in extreme environments.
• Levels of organisation in an ecosystem
• Required practical: sampling with quadratsRequired practical — Estimate population size; use transects for distribution along a gradient.
• Feeding relationships — Producer, consumer, predator, prey; interpret predator-prey graphs.
• Water cycle — Describe evaporation, transpiration, condensation, precipitation.
• Carbon cycle — Roles of photosynthesis, respiration, combustion and decomposition.
• Required practical: decay (Biology only)Required practicalTriple only — Effect of temperature on rate of milk decay using lipase or pH change.
• Biodiversity — Define biodiversity; explain how a high level supports ecosystem stability.
• Human impact — Pollution of water, land and air; effect of waste, deforestation and global warming.
• Maintaining ecosystems — Conservation, reforestation, breeding programmes, hedgerow/field margin schemes.
• Trophic levels (Biology only, Higher)HigherTriple only — Pyramids of biomass; calculate efficiency of biomass transfer.
• Food security (Biology only)Triple only — Biological factors affecting food security; sustainable fisheries; role of biotechnology.

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