GAMSAT Biology Topics 2026 — High-Yield Section III Biology Content

Replication fork mechanics (helicase, primase, DNA polymerase III, ligase), leading vs lagging strand, Okazaki fragments, telomere replication, proofreading (3' to 5' exonuclease), mismatch repair, nucleotide excision repair, double-strand break repair (NHEJ vs homologous recombination).

Study tip: GAMSAT stimuli often present an unfamiliar repair mechanism or a mutant polymerase. Focus on understanding the logic of each step rather than memorising enzyme names — the passage will provide specific details.

RNA polymerase II, promoter recognition, transcription factors, mRNA processing (5' cap, 3' poly-A tail, splicing via spliceosome), alternative splicing, gene regulation in prokaryotes (lac operon, trp operon) and eukaryotes (enhancers, silencers, chromatin remodelling, histone acetylation, DNA methylation), miRNA and siRNA post-transcriptional regulation.

Study tip: Gene regulation is a passage-driving topic — expect stimuli describing an unfamiliar operon or regulatory element. Know the general principles (positive vs negative regulation, cis vs trans elements) so you can reason about novel systems.

Ribosome structure (40S/60S in eukaryotes, 30S/50S in prokaryotes), initiation (Shine-Dalgarno in prokaryotes, Kozak in eukaryotes), elongation, termination, tRNA charging and wobble hypothesis, post-translational modifications (phosphorylation, glycosylation, ubiquitination), protein folding and chaperones, proteasome degradation.

Study tip: Know the differences between prokaryotic and eukaryotic translation — GAMSAT can present antibiotic mechanisms that target specific ribosomal subunits as stimulus passages.

Michaelis-Menten equation (Vmax, Km), Lineweaver-Burk double-reciprocal plots, competitive vs non-competitive vs uncompetitive inhibition (graphical identification), allosteric regulation, cooperativity and Hill coefficient, covalent modification (phosphorylation), zymogen activation, feedback inhibition.

Study tip: This topic straddles the biology-chemistry boundary. Be able to read and interpret Lineweaver-Burk plots from stimulus data — GAMSAT frequently provides unfamiliar enzyme data and asks you to identify the inhibition type.

Glycolysis (10 steps, regulated enzymes: hexokinase, PFK-1, pyruvate kinase), pyruvate dehydrogenase complex, citric acid cycle (inputs, outputs, regulation), electron transport chain (Complexes I-IV, ubiquinone, cytochrome c), chemiosmotic coupling (ATP synthase mechanism), substrate-level vs oxidative phosphorylation, ATP yield accounting, anaerobic fermentation (lactate and ethanol pathways), gluconeogenesis.

Study tip: Know the net ATP yield and the regulated steps. GAMSAT stimuli often present metabolic poisons (rotenone, cyanide, oligomycin, 2,4-DNP) and ask you to predict the effect on ATP production. Understand each complex so you can reason about novel inhibitors.

Autosomal dominant/recessive inheritance, X-linked inheritance, codominance, incomplete dominance, epistasis, polygenic inheritance, pedigree analysis, Hardy-Weinberg equilibrium (assumptions, equation, application), linkage and recombination, genetic mapping, chi-square test for genetic ratios.

Study tip: GAMSAT genetics questions often present a pedigree or cross data and ask you to determine the inheritance pattern. Practice quickly identifying autosomal vs X-linked from pedigree structure. Hardy-Weinberg is straightforward marks if you know the formula and its assumptions.

Phospholipid bilayer structure, integral vs peripheral proteins, simple diffusion, facilitated diffusion (channels and carriers), primary active transport (Na/K ATPase, Ca ATPase), secondary active transport (symporters and antiporters), osmosis and tonicity, endocytosis and exocytosis. Cell signalling: G-protein-coupled receptors, receptor tyrosine kinases, second messengers (cAMP, IP3, DAG, Ca2+), MAPK cascade, cell cycle checkpoints, cyclins and CDKs.

Study tip: Membrane transport questions often combine biology with chemistry (concentration gradients, electrochemical potential). Cell signalling passages may present an unfamiliar receptor or pathway — focus on understanding the general logic of signal transduction cascades.

Heart anatomy and blood flow, cardiac cycle (systole/diastole), pressure-volume relationship, electrical conduction system (SA node, AV node, bundle of His, Purkinje fibres), ECG interpretation, blood pressure regulation (baroreceptor reflex, RAAS), oxygen-haemoglobin dissociation curve (Bohr effect, 2,3-BPG), blood vessel structure and function.

Study tip: The oxygen-haemoglobin dissociation curve is a GAMSAT favourite — know how pH, temperature, CO2, and 2,3-BPG shift the curve and why. Stimuli may present a clinical scenario with abnormal blood gases.

Nephron anatomy (glomerulus, PCT, loop of Henle, DCT, collecting duct), glomerular filtration (GFR, filtration fraction), tubular reabsorption and secretion, counter-current multiplier system (loop of Henle), ADH and water reabsorption, aldosterone and sodium reabsorption, RAAS pathway, acid-base regulation (bicarbonate reabsorption, H+ secretion, ammonium excretion), clearance calculations.

Study tip: Renal passages are common and tend to involve data interpretation — clearance calculations, GFR estimation from inulin or creatinine data. Practice working through these quantitatively.

Lung mechanics (inspiration/expiration, diaphragm and intercostals), lung volumes and capacities (tidal volume, vital capacity, residual volume, FRC, TLC), alveolar gas exchange (partial pressures, Dalton's law, Henry's law), oxygen and CO2 transport in blood, ventilation-perfusion matching, central and peripheral chemoreceptors.

Study tip: Gas exchange questions often require you to apply Dalton's law or understand partial pressure gradients. Know the difference between ventilation and perfusion and what happens when they are mismatched.

Hypothalamic-pituitary axes (HPA, HPT, HPG), negative feedback mechanisms, peptide vs steroid hormone signalling pathways, insulin and glucagon (glucose homeostasis), cortisol stress response, thyroid hormones (T3/T4 synthesis and regulation), adrenal medulla (adrenaline/noradrenaline), growth hormone, calcium homeostasis (PTH, calcitonin, vitamin D).

Study tip: GAMSAT endocrine questions typically present a clinical scenario with hormone level data and ask you to identify the dysfunction. Know the feedback loops well enough to predict what happens when a gland is overactive or underactive.

Resting membrane potential (Nernst equation, Goldman equation), action potential generation and propagation, voltage-gated Na+ and K+ channels, refractory periods, saltatory conduction in myelinated neurons, synaptic transmission (chemical synapse, neurotransmitter release, receptor types), neuromuscular junction, autonomic nervous system (sympathetic vs parasympathetic).

Study tip: Action potential mechanics are well-suited to stimulus-based questions — expect passages presenting novel channel mutations or drug effects and asking you to predict the electrophysiological consequence.

Innate immunity (physical barriers, phagocytes, complement system, inflammation), adaptive immunity (B cells and antibody-mediated immunity, T cells and cell-mediated immunity), antibody structure and classes (IgM, IgG, IgA, IgE, IgD), MHC class I vs class II antigen presentation, clonal selection, immunological memory, vaccines, hypersensitivity reactions, autoimmunity basics.

Study tip: Immunology passages may describe an unfamiliar immune response or a vaccine mechanism. Know the distinction between innate and adaptive, and between humoral (B cell) and cell-mediated (T cell) immunity.

Amino acid classification (nonpolar, polar, charged), pKa and isoelectric point calculations, peptide bond formation and properties, protein structure levels (primary through quaternary), alpha helix and beta sheet, disulphide bonds, hydrophobic interactions, denaturation and renaturation, protein folding diseases (prion diseases, amyloidosis).

Study tip: Amino acid chemistry straddles biology and chemistry. Be confident with pKa calculations and predicting charge state at a given pH — this is a frequently tested quantitative skill on GAMSAT.

Fatty acid structure (saturated, unsaturated, essential), beta-oxidation (cycle, ATP yield per fatty acid), ketogenesis and ketone body metabolism, triglyceride synthesis and storage, cholesterol synthesis pathway (HMG-CoA reductase), lipoproteins (chylomicrons, VLDL, LDL, HDL), phospholipid and membrane structure.

Study tip: Beta-oxidation ATP yield calculations occasionally appear. Know the general cycle and be able to calculate ATP yield for a given fatty acid chain length.

Restriction enzymes and restriction mapping, plasmid vectors and cloning, PCR (primers, Taq polymerase, thermal cycling), gel electrophoresis (agarose for DNA, SDS-PAGE for proteins), Southern blot, Northern blot, Western blot, DNA sequencing (Sanger method), CRISPR-Cas9 genome editing, gene expression analysis (RT-PCR, microarray, RNA-seq).

Study tip: Experimental techniques are common stimulus material — expect a passage describing a cloning experiment or a gel result and asking you to interpret the data. Know what each technique tells you and its limitations.

Natural selection (directional, stabilising, disruptive), genetic drift, gene flow, speciation (allopatric, sympatric), adaptive radiation, evidence for evolution (comparative anatomy, molecular phylogenetics, fossil record), phylogenetic tree interpretation.

Study tip: Evolution questions are less frequent but can appear as multi-question stimulus passages about population genetics or phylogenetic data. Hardy-Weinberg is the highest-yield sub-topic within evolution.

Population growth models (exponential, logistic), carrying capacity, r-selected vs K-selected species, predator-prey dynamics (Lotka-Volterra), competition (competitive exclusion), food webs and trophic levels, energy flow through ecosystems, biogeochemical cycles (carbon, nitrogen, phosphorus).

Study tip: Ecology is the lowest-yield biology domain for GAMSAT. Cover population growth models and trophic-level energy transfer at a basic level. Do not invest significant time unless all higher-yield topics are mastered.

Photosynthesis (light reactions, Calvin cycle, C3/C4/CAM plants), plant hormones (auxin, cytokinin, gibberellin, ethylene, abscisic acid), plant structure (roots, stems, leaves), water transport (transpiration, cohesion-tension theory), mineral nutrition.

Study tip: Photosynthesis chemistry (light reactions and Calvin cycle) is the only consistently tested plant topic. Skip detailed plant anatomy and reproduction unless you have completed all higher-yield domains.

Bacterial cell structure (cell wall, capsule, flagella, plasmid), binary fission, horizontal gene transfer (conjugation, transduction, transformation), viral structure and replication cycles (lytic vs lysogenic), bacteriophages, antibiotic mechanisms and resistance.

Study tip: Microbiology stimuli on GAMSAT often involve antibiotic resistance mechanisms or viral replication — understand the principles well enough to reason about novel scenarios presented in the passage.