Biology ATAR Units 3 and 4 connect heredity and evolution with homeostasis and infectious disease. These original ATARMAxxing resources follow the current SCSA syllabus. The platform is not affiliated with SCSA or TISC; original practice material is separate from linked official examinations.
Biology ATAR Year 12 syllabus — for teaching from January 2024 · guide last reviewed . Always check the current syllabus on the SCSA site ↗.
School assessment comprises Science inquiry 20%, Extended response 10%, Test 20% and Examination 50%. The external examination permits 10 minutes reading followed by 180 minutes working. Section One is 30 compulsory multiple-choice questions (30%); Section Two is 4–6 compulsory short-answer questions (50%); Section Three offers four 20-mark questions and requires one Unit 3 response plus one Unit 4 response (20%). The frozen model uses the 2025 raw structure: 30 + 100 + 40 = 170 candidate marks, while 210 marks are offered. Total 100 is the percentage column. Up to three calculators unable to create or store programs or text are permitted; no data or formula booklet is listed.
Past papers on this subject span more than one syllabus. Papers written under an older one still work as practice, but the units and content areas they test have changed — the index labels every paper with the syllabus it was set under.
Each area below lists the concepts named in the syllabus, what the SCSA exam asks of them, and the mistake that most often costs marks.
Cell division, DNA replication and expression, mutation, variation and inheritance patterns explain continuity and diversity.
Trace mechanisms, solve inheritance probabilities and justify genotypes from evidence.
Mitosis and meiosis have different products; probability is not certainty; epigenetics is not required.
PCR, electrophoresis, sequencing, profiling and recombinant DNA provide evidence and practical applications.
Interpret controls, bands and sequence evidence and evaluate benefits, limitations and risks.
PCR amplifies a target; gels separate fragments. A matching profile is evidence, not automatic proof of identity.
Evidence supports common ancestry; mutation, selection, drift, founder effect and gene flow alter gene pools.
Calculate frequencies and distinguish random from selective processes when explaining change and speciation.
Individuals do not evolve and organisms do not acquire mutations because they need them.
Negative feedback and structural, behavioural and physiological adaptations maintain variables within tolerance limits.
Trace stimulus, receptor, control, effector and response; compare water, salt and temperature adaptations.
Homeostasis maintains a range, not a fixed value; ectotherms also regulate behaviourally.
Pathogen structure, life cycles, transmission, host density, movement and climate shape outbreaks and control.
Analyse epidemic data and evaluate quarantine, herd immunity, physical controls and antimicrobials.
Phytophthora is treated as Protista in this syllabus; antibiotics do not treat viruses.
No. Choose one of two Unit 3 questions and one of two Unit 4 questions.
The raw candidate pathway is 30 + 100 + 40. The cover's total 100 is the sum of percentage weights.
No. Four are offered, but only two are attempted in fixed unit groups.
The current syllabus explicitly says epigenetics is not required.
No. Biology has course code BLY and distinct Unit 3 and Unit 4 content.
No. Practice papers are original; official SCSA papers and keys are linked separately.
Knowing the syllabus is the first half. The other half is seeing how SCSA actually asks it — every official paper for Biology is indexed by the same areas above.