HSC Biology · Year 12
HSC Biology: what actually gets examined
Every question from 4 official NESA papers, coded by module, topic and marks — so you can decide what to revise from evidence rather than a feeling.
4 NESA papers, 2022–2025 · 176 questions · 400 marks
12 of the 17 topics in HSC Biology were examined in every paper on file, and the 4 modules carry almost identical weight. There is nothing here you can safely skip — the question is what order you revise in.
Counted from 4 official NESA Biology papers (2022–2025). 176 questions, 400 marks. Nothing estimated.
The key words that carry the paper
Share of written-response questions by NESA key word. Revising the content without revising the directive is how marks get lost. The lower / middle / higher grouping is ours — NESA publishes the glossary but does not band it. Based on the 52% of written responses that open with a glossary key word; the rest open with wording outside it, such as “State” or a direct question.
Lower orderMiddle orderHigher order
Each tile is one key word; its size is that key word's share of written-response questions that open with one. The smallest 2 are grouped as Other: Discuss 2% · 1q, Evaluate 4% · 2q.
Where the marks sit
Each module with its topics underneath. The bar is that topic's share of its own module, and the chip says how many of the papers on file examined it.
Module 5: Heredity
103 marks25% indicative weighting, quoted from the syllabus
11 questions · 26% of this module
15 questions · 26% of this module
11 questions · 25% of this module
10 questions · 14% of this module
4 questions · 9% of this module
Concept pages in this module:
Module 6: Genetic Change
100 marks25% indicative weighting, quoted from the syllabus
21 questions · 48% of this module
14 questions · 31% of this module
7 questions · 21% of this module
Concept pages in this module:
Module 7: Infectious Disease
101 marks25% indicative weighting, quoted from the syllabus
18 questions · 35% of this module
16 questions · 35% of this module
8 questions · 21% of this module
6 questions · 10% of this module
Concept pages in this module:
Module 8: Non-infectious Disease and Disorders
97 marks25% indicative weighting, quoted from the syllabus
10 questions · 28% of this module
12 questions · 22% of this module
10 questions · 22% of this module
8 questions · 16% of this module
3 questions · 12% of this module
Concept pages in this module:
Across 4 papers the modules carried 103, 100, 101, 97 marks — against a 25% indicative weighting each, quoted from the NESA Biology Stage 6 Syllabus (2017). The counted share and the published weighting are two different measures.
How each topic gets asked
The 6 biggest topics, by the shape of the questions actually set on them. Revising the content without revising the directive is how marks get lost — the key words below are NESA's own, counted from the papers.
Mutation
Module 6: Genetic Change · 48 marks across 21 questions
Asked as Multiple choice ×11 · Short answer ×8 · Extended response ×2
NESA key words Evaluate ×2 · Describe ×1 · Explain ×1 · Outline ×1 · Identify ×1
Causes of Infectious Disease
Module 7: Infectious Disease · 35 marks across 18 questions
Asked as Multiple choice ×8 · Short answer ×7 · Extended response ×3
NESA key words Describe ×2 · Outline ×2
Prevention, Treatment and Control
Module 7: Infectious Disease · 35 marks across 16 questions
Asked as Multiple choice ×7 · Short answer ×5 · Extended response ×4
NESA key words Explain ×2 · Identify ×1 · Justify ×1
Genetic Technologies
Module 6: Genetic Change · 31 marks across 14 questions
Asked as Multiple choice ×6 · Short answer ×6 · Extended response ×2
NESA key words Describe ×2 · Compare ×1 · Outline ×1 · Explain ×1
Reproduction
Module 5: Heredity · 27 marks across 11 questions
Asked as Multiple choice ×4 · Short answer ×5 · Extended response ×2
NESA key words Identify ×1 · Outline ×1 · Explain ×1
Genetic Variation
Module 5: Heredity · 27 marks across 15 questions
Asked as Multiple choice ×8 · Short answer ×6 · Extended response ×1
NESA key words Compare ×1 · Outline ×1 · Analyse ×1
How the paper is built
Marks by question format across the same 4 papers.
Multiple choice is exactly 20 marks in every paper. The rest moves around: short answer ran 44, 56, 51, 60 marks and extended response ran 36, 24, 29, 20 marks. 4 papers is not enough to call that a trend.
The papers this is counted from
NSW Education Standards Authority publishes every paper and its marking guidelines. These links go to NESA's own copies — read the questions there.
These are the external examination papers. They are not the whole subject: Biology is also assessed by school-based assessment set and marked by your school, which NESA does not publish — so nothing on this page covers that part of your result.
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Frequently Asked Questions
Which HSC Biology topics come up every year?
12 of the 17. Every topic marked "Every paper" above was examined in all 4 papers on file. That describes the papers analysed, not a prediction — examiners set each paper fresh.
Which HSC Biology module is worth the most marks?
Module 5: Heredity 103, Module 7: Infectious Disease 101, Module 6: Genetic Change 100, Module 8: Non-infectious Disease and Disorders 97 marks across the 4 papers analysed. The syllabus publishes an indicative weighting for each; the counted share and the published weighting are two different measures.
What is the biggest single topic in HSC Biology?
Mutation, with 48 of the 400 marks counted across 4 papers.
How was this analysed?
Every question in 4 official NESA HSC Biology papers (2022–2025) was counted against the NESA Biology Stage 6 Syllabus (2017): its mark value, its format and its key word, and the module and topic it assesses. Marks are reconciled against each paper's own stated total.
Are the exam questions reproduced here?
No. NSW Education Standards Authority owns the papers. This page publishes counts and links to NESA's own copy of each paper so you can read the questions at the source. The analysis is ours; the papers stay with NESA.
Does this predict what will be in my exam?
No, and it is not meant to. It describes what has been set. Examiners write each paper fresh and can weight a neglected topic heavily, which is why every topic is listed here, including the ones examined least.
Coded against the NESA Biology Stage 6 Syllabus (2017). Where a question is coded to more than one topic its marks are split evenly, so topic totals within a module can round a mark or two above the module total. A topic is marked "Every paper" when it appears in all 4, "Most papers" when it is missing from one, and "Comes and goes" when it is missing from more — the one-paper tolerance absorbs a single coding miss rather than publishing it. Last updated 2026-08-30 · Exam papers © NSW Education Standards Authority, linked at source.