Biology (AM syllabus content)
Domain overview
MATSEC AM Biology tests advanced understanding of molecules, cells, whole organisms and populations, and your ability to move between those scales. Questions often combine recall with explanation, data interpretation and experimental design, so a definition alone rarely earns full marks. Expect to compare structures, explain processes in sequence, interpret graphs and tables, and justify conclusions.
Core rules and concepts
- Structure–function links: relate membrane phospholipid arrangement to selective permeability; protein tertiary structure to active-site specificity; leaf anatomy to gas exchange and light capture.
- Energy and control: trace respiration and photosynthesis through electron transport and chemiosmosis; explain homeostasis as negative feedback with receptors, effectors and set points.
- Information flow: link DNA replication, transcription and translation to phenotype; use meiosis and fertilisation to explain genetic variation.
- Inheritance and statistics: apply Mendelian ratios, recognise linkage and epistasis, and test observed ratios with chi-square.
- Ecology and evolution: explain population growth, succession, nutrient cycling and natural selection as processes with evidence.
Worked example
Two heterozygous tall pea plants (Tt × Tt) are crossed. What proportion of the tall offspring is expected to be heterozygous? Reasoning: a Punnett square gives 1 TT : 2 Tt : 1 tt. Tall offspring are TT or Tt, so there are 3 tall parts. Two of those are Tt. The answer is therefore 2/3, not 1/2. The phrase ‘of the tall offspring’ changes the denominator; if the question asked for heterozygous plants among all offspring, the answer would be 1/2.
Traps that cost marks
Do not confuse competitive and non-competitive inhibition; state whether the inhibitor binds the active site or elsewhere. In ecology, separate observations from inferences. In genetics, distinguish genotype from phenotype. Always name the controlled variables and a suitable control when describing an experiment, and use units on graph axes.