ZIMSEC · Form 5 · Lower 6 · Syllabus 6030
Biology
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- Biological molecules Triglycerides: glycerol + three fatty acids joined by ester bonds. Saturated fatty acids have no C=C. Phospholipids have a hydrophilic phosphate head and hydrophobic tails, forming bilayers. Functions: energy store, insulation, membranes, waterproofing.
- Cell structure and membranes Light microscopes resolve about 200 nm; electron microscopes about 0.5–1 nm (TEM for internal detail, SEM for surfaces). Magnification = image size ÷ actual size.
- Enzymes Enzymes are globular proteins that lower the activation energy of reactions. The substrate binds to the complementary active site, forming an enzyme–substrate complex.
- Nucleic acids, protein synthesis and cell division Semi-conservative: the helix unwinds (helicase), each strand acts as a template, free nucleotides pair up, and DNA polymerase joins them. Each new molecule has one old and one new strand (shown by Meselson and Stahl).
- Transport in mammals and plants Mammals The cardiac cycle: atrial systole, ventricular systole, diastole. The sinoatrial node (pacemaker) starts the heartbeat; the atrioventricular…
- Ecology, biodiversity and immunity Ecology Energy flow: producers fix about 1–3% of light energy (gross primary productivity); net primary productivity = GPP…