Biology Subject Content Knowledge
The Biology subject content knowledge domain tests your grasp of the SHS biology syllabus and your ability to apply it to unfamiliar scenarios, not just recall definitions. Questions range across cell biology, genetics, physiology, ecology, evolution and classification, often asking you to interpret data or predict outcomes.
Core content anchors
- Cell biology: membranes, osmosis, diffusion and active transport; enzyme action and denaturation; photosynthesis and respiration as complementary processes.
- Genetics: mitosis versus meiosis; monohybrid crosses; codominance and multiple alleles; sex-linked inheritance; mutation and variation.
- Physiology: homeostasis, gas exchange, transport, excretion, and nervous and hormonal coordination.
- Ecology and evolution: trophic levels, energy flow, nutrient cycles, natural selection and adaptation.
- Classification: binomial nomenclature, hierarchical taxa and distinguishing features of major groups.
Worked example
A woman with blood group A (genotype I^A i) and a man with blood group B (I^B i) have children. What blood groups are possible?
Reasoning: each parent produces two gamete types - I^A or i, and I^B or i. Combining them gives I^A I^B (AB), I^A i (A), I^B i (B) and ii (O). The expected ratio is 1 AB : 1 A : 1 B : 1 O. This is a multiple-allele, codominance problem: A and B alleles are codominant, and both are dominant to i. The answer is not “only AB” because each parent can pass the recessive i allele.
Traps that cost marks
- Treating dominance as “more common” or “stronger”; dominance describes expression in the heterozygote.
- Saying osmosis moves “water and solutes”; osmosis is water movement across a partially permeable membrane.
- Mixing mitosis and meiosis: mitosis gives two genetically identical diploid cells; meiosis gives four genetically varied haploid cells.
- Writing species names incorrectly: genus capitalised, species lower case, both italicised or underlined.
- Claiming that a correlation in an ecology graph proves causation.
Command words
“Describe” needs features; “explain” needs a mechanism; “evaluate” needs a judgement supported by evidence. Match the length and structure of your answer to the command word.