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Cambridge · Form 4 · Syllabus 5090

Biology

5 topics5 with notes

ZIMSEC Form 4 Cambridge Form 4
Form 4Writing O Level finals this year?Revision mode: every Biology past paper by year, with marking schemes, and a checklist of the whole syllabus.
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  1. Human nutrition, transport and gas exchange Balanced diet; deficiency diseases (scurvy, rickets, kwashiorkor); the alimentary canal; mechanical and chemical digestion; enzymes (amylase, protease, lipase); bile emulsifies fats; hydrochloric acid kills microbes and gives the optimum pH for pepsin; absorption in the small intestine via villi; water absorption in the colon. Notes 1 PDF
  1. Diseases and immunity Pathogens (bacteria, viruses, fungi, protoctists) cause transmissible diseases spread by direct contact, contaminated food and water, air and vectors (e.g. Anopheles mosquitoes and malaria). Notes 1 PDF
  2. Excretion, homeostasis and coordination Removal of metabolic waste: carbon dioxide (lungs), urea (kidneys). Urea is made in the liver by deamination of excess amino acids. The kidney filters blood (glomerulus) and reabsorbs useful substances (glucose, water, some salts). Dialysis and transplants treat kidney failure. Notes 1 PDF
  3. Reproduction, inheritance and evolution Asexual (one parent, genetically identical offspring) and sexual (gametes fuse, variation). Flowering plants: pollination (insect and wind), fertilisation, seed and fruit formation, germination conditions. Humans: reproductive systems, menstrual cycle, fertilisation, pregnancy, placenta, birth; sexually transmitted infections. Notes 1 PDF
  1. Ecology and human influences on ecosystems Food chains and webs; producers, consumers and decomposers; trophic levels; pyramids of numbers, biomass and energy. Energy is lost at each level (respiration, heat, waste), so food chains are short. Notes 1 PDF