Biology revision notes

One chapter for each section of the 5090 syllabus, with worked examples. Read a chapter, then practise it with real past-paper questions.

1. 1Cells and OrganisationAnimal, plant and bacterial cells and the functions of their parts, using a microscope, specialised cells, tissues, organs and organ systems, and calculating magnification.6 min read
2. 2ClassificationClassifying organisms, species and the binomial system, dichotomous keys, the five kingdoms, the main groups of vertebrates and arthropods, ferns and flowering plants, and viruses.6 min read
3. 3Movement In and Out of CellsWater as a solvent, diffusion and the factors that affect it, osmosis and water potential, turgor and plasmolysis in plant cells, and active transport.7 min read
4. 4Biological MoleculesThe elements in carbohydrates, lipids, proteins and DNA, how large molecules are built from smaller ones, and the food tests for starch, reducing sugars, protein and lipids.3 min read
5. 5EnzymesCatalysts and enzymes, how enzymes work with their substrates (the lock and key hypothesis), and the effects of temperature and pH on enzyme activity.5 min read
6. 6Plant NutritionPhotosynthesis, its equation, uses of the carbohydrates made and the factors that limit its rate, the structure of a leaf, and the mineral ions that plants need.7 min read
7. 7Plant TransportWater and ion uptake by root hair cells, the path of water through the plant, transpiration and the factors that affect it, the transpiration stream, translocation, and the structure of xylem.6 min read
8. 8Human NutritionDiet and deficiency diseases, the human digestive system, teeth, enzymes and digestion, bile, peristalsis, and absorption and assimilation in the small intestine.9 min read
9. 9Human Gas ExchangeThe gas exchange system, alveoli and their adaptations, inspired and expired air, how breathing works, the effect of exercise on breathing, and how the airways protect against pathogens and particles.5 min read
10. 10RespirationRespiration and the uses of energy, aerobic respiration and its equation, anaerobic respiration in humans and yeast, lactic acid and the oxygen debt.4 min read
11. 11Human TransportThe double circulatory system, the structure and action of the heart, coronary heart disease, the blood vessels, and the components and functions of blood.8 min read
12. 12Disease and ImmunityPathogens and transmissible disease, malaria, HIV and AIDS, cholera, alcohol and tobacco, drugs and antibiotics, and active and passive immunity including vaccination.8 min read
13. 13ExcretionExcretion and its importance, the urinary system, the structure and function of the nephron, and the role of the liver in deamination and in making urea.4 min read
14. 14Coordination and HomeostasisThe nervous system, neurones, reflex arcs and synapses, the eye, hormones and adrenaline, homeostasis and negative feedback, temperature control in the skin, and blood glucose control and diabetes.10 min read
15. 15Coordination in PlantsGravitropism and phototropism, the role of auxin in controlling shoot growth, and investigating plant responses.3 min read
16. 16ReproductionChromosomes, mitosis and meiosis, stem cells and cancer, asexual and sexual reproduction, flowers, pollination, fertilisation, seeds and germination, and human reproduction including the menstrual cycle and the placenta.12 min read
17. 17Inheritance and VariationContinuous and discontinuous variation, the structure of DNA and genes, monohybrid crosses and Punnett squares, codominance, sex determination, mutation, and natural and artificial selection.9 min read
18. 18Biotechnology and Genetic ModificationThe use of yeast and bacteria, fermenters, enzymes in industry, genetic modification and its uses in bacteria and crop plants, and the advantages and risks.4 min read
19. 19Organisms and the EnvironmentEnergy flow, food chains and webs, pyramids, the carbon and nitrogen cycles, populations, communities and ecosystems, the effects of humans, and conservation.9 min read