QCE Biology most tested topics
Across the 12 QCAA Biology external papers from 2020 to 2025, Genetics and heredity leads on 27.5% and Biodiversity and populations trails on 21.4%, with the rest between them. At dot-point level 3.1.6 and 3.1.7 carry 5.2% of paper marks each, and four of the 56 dot points that the board assesses externally have not appeared in one of these papers. Every percentage below covers the 93.2% of marks that map to a syllabus dot point.
Computed from 12 QCAA Biology external papers, 2020 to 2025: 230 questions, 319 question parts and 556 marks.
Unit, topic and dot-point shares below are of the 518 marks that map to a dot point, so each of those tables adds to 100%. 25 of the 319 parts are assessed against more than one dot point, and their 60 marks are divided evenly between the dot points they cover.
What these papers are
| Year | Paper | Questions | Marks |
|---|---|---|---|
| 2025 | Paper 1 | 26 | 49 |
| 2025 | Paper 2 | 11 | 52 |
| 2024 | Paper 1 | 27 | 47 |
| 2024 | Paper 2 | 11 | 50 |
| 2023 | Paper 1 | 27 | 46 |
| 2023 | Paper 2 | 9 | 43 |
| 2022 | Paper 1 | 28 | 42 |
| 2022 | Paper 2 | 11 | 45 |
| 2021 | Paper 1 | 28 | 50 |
| 2021 | Paper 2 | 13 | 42 |
| 2020 | Paper 1 | 28 | 45 |
| 2020 | Paper 2 | 11 | 45 |
Marks by unit
| Unit | Share of marks |
|---|---|
| Unit 4: Heredity and continuity of life | 53.1% |
| Unit 3: Biodiversity and the interconnectedness of life | 46.9% |
Marks by topic
| Topic | Share of marks | Papers it appears in | Years |
|---|---|---|---|
| Genetics and heredity | 27.5% | 12 of 12 | 6 of 6 |
| Continuity of life on Earth | 25.6% | 12 of 12 | 6 of 6 |
| Functioning ecosystems and succession | 25.5% | 12 of 12 | 6 of 6 |
| Biodiversity and populations | 21.4% | 12 of 12 | 6 of 6 |
Marks by dot point
Dot-point numbers and wording are QCAA's own. Where a dot point is written as a list, its items run together here separated by semicolons.
| Dot point | Content | Topic | Share of marks | Papers |
|---|---|---|---|---|
| 3.1.6 | Determine the diversity of species using measures such as species richness, evenness (relative species abundance), percentage cover, percentage frequency and Simpson's diversity index, | Biodiversity and populations | 5.2% | 10 of 12 |
| 3.1.7 | Describe how sampling can be used to investigate the species diversity of a given area, considering the most appropriate sampling method: random, systematic, stratified; sampling technique: quadrats, line transect, belt-transect, capture-recapture; strategies to minimise bias: size and number of samples, random-number generators, counting criteria, calibrating equipment and noting associated precision; measure/s of diversity | Biodiversity and populations | 5.2% | 7 of 12 |
| 4.1.1 | Describe the structure and function of DNA, genes and chromosomes in prokaryotes and eukaryotes, including helical structure, nucleotide composition (nitrogenous base + sugar + phosphate), complementary base pairing, hydrogen bonds; introns and exons, promoter region; homologous chromosomes (i.e. sister chromatids, centromeres, telomeres, gene loci, alleles), role of histones; circular chromosomes (i.e. prokaryotes, mitochondria, chloroplasts) and plasmids | Genetics and heredity | 4.2% | 9 of 12 |
| 4.1.13 | Infer patterns of inheritance and predict frequencies of genotypes and phenotypes from genetic data, including histograms (polygenic inheritance); pedigrees (dominant/recessive, autosomal/sex-linked); Punnett squares (dominant/recessive, autosomal/sex-linked and multiple-allele inheritance) | Genetics and heredity | 4.2% | 6 of 12 |
| 4.2.7 | Explain how geographic, temporal and spatial isolation influence gene flow and may lead to allopatric, sympatric and parapatric speciation | Continuity of life on Earth | 4.1% | 8 of 12 |
| 4.2.10 | Infer species relatedness from cladograms, phylograms and molecular sequence data | Continuity of life on Earth | 3.9% | 8 of 12 |
| 3.2.2 | Analyse food chains, energy flow diagrams and ecological pyramids to determine efficiencies of energy and biomass transfer; gross and net productivity; loss of energy through radiation, reflection and absorption | Functioning ecosystems and succession | 3.7% | 7 of 12 |
| 3.2.10 | Explain how the carrying capacity of an ecosystem can be impacted by changes to biotic and abiotic factors, including climatic events | Functioning ecosystems and succession | 3.5% | 8 of 12 |
| 4.2.3 | Explain natural selection and identify the three main types of phenotypic selection: stabilising, directional and disruptive | Continuity of life on Earth | 3.5% | 8 of 12 |
| 4.1.2 | Describe the process of DNA replication with reference to helicase, DNA polymerase and the joining of Okazaki fragments | Genetics and heredity | 3.1% | 6 of 12 |
| 4.1.8 | Explain the process of protein synthesis in terms of transcription of a gene into messenger RNA in the nucleus; RNA processing (5' cap, RNA splicing, poly-A tail); translation of mRNA into an amino acid sequence at the ribosome, referring to transfer RNA, codons and anticodons | Genetics and heredity | 2.9% | 6 of 12 |
| 4.2.5 | Analyse data to determine the effect of a selection pressure on a population, recognising that selection for an allele can be positive or negative | Continuity of life on Earth | 2.9% | 8 of 12 |
| 4.1.4 | Describe the process of meiosis and explain how crossing over, independent assortment and random fertilisation produce variation in the genotypes of offspring | Genetics and heredity | 2.7% | 4 of 12 |
| 3.1.12 | Identify and explain different modes of population growth, including exponential growth (J-curve); logistic growth (S-curve) | Biodiversity and populations | 2.5% | 7 of 12 |
| 4.2.2 | Explain microevolutionary change through the main processes of mutation, gene flow and genetic drift | Continuity of life on Earth | 2.4% | 7 of 12 |
| 4.2.6 | Describe how macroevolutionary changes result from the accumulation of microevolutionary changes using examples of divergent, convergent, parallel and coevolution | Continuity of life on Earth | 2.4% | 6 of 12 |
| 4.1.10 | Explain how gene expression is regulated in response to environmental signals and to allow for cell differentiation, including chemical tags that affect chromatin structure (heterochromatin vs. euchromatin); proteins that bind to the promoter region of a gene (transcription factors) | Genetics and heredity | 2.1% | 5 of 12 |
| 3.2.12 | Distinguish between primary and secondary succession | Functioning ecosystems and succession | 2.0% | 6 of 12 |
These 18 dot points carry 60.5% of the paper marks between them. Another 34 assessed dot points share the rest, and 4 of the 56 externally assessable dot points have not been assessed in any of these 12 papers. Content that has not appeared is still examinable.
What has moved between papers
No topic's share moved by more than 3.0 percentage points between the 2020 to 2022 papers and the 2023 to 2025 papers. The largest movement was 1.6 points, which is inside the range two papers a year produce by chance, so nothing here is a trend to revise around.
How the papers are built
Short answer carries 78.4% of the marks across these 12 papers.
| Question type | Share of marks | Marks | Parts |
|---|---|---|---|
| Short answer | 78.4% | 436 | 199 |
| Multiple choice | 21.6% | 120 | 120 |
| Verb | Share of marks | Marks | Parts |
|---|---|---|---|
| explain | 28.6% | 159 | 63 |
| describe | 15.8% | 88 | 34 |
| identify | 14.7% | 82 | 40 |
| predict | 5.4% | 30 | 12 |
| justify | 5.2% | 29 | 12 |
| infer | 4.9% | 27 | 12 |
| determine | 4.5% | 25 | 14 |
| compare | 3.4% | 19 | 6 |
What these percentages do not tell you
Where to practise
Every topic above links to its own page of real QCAA questions with marking criteria and average scores attached: Genetics and heredity, Continuity of life on Earth, Functioning ecosystems and succession and Biodiversity and populations. For how students actually score on this content, read QCE Biology hardest topics, and for the full question bank start at QCE Biology.
Frequently asked questions
Which topic carries the most marks in the QCE Biology external exam?
Genetics and heredity carries 27.5% of the marks across the 12 QCAA papers from 2020 to 2025, ahead of Continuity of life on Earth on 25.6%.
How are marks split between question types in the QCE Biology exam?
Short answer carries 78.4% of the marks and multiple choice carries 21.6% of the marks, measured across 12 papers and 556 marks from 2020 to 2025.
Has the topic balance changed in recent QCE Biology papers?
No. Comparing the 2020 to 2022 papers with the 2023 to 2025 papers, the largest movement in any topic's share was 1.6 percentage points, which is too small to plan revision around.
How many past papers is this QCE Biology analysis based on?
12 QCAA external papers from 2020 to 2025, covering 230 questions and 556 marks. 6.8% of those marks carry no dot-point mapping and sit outside the percentages.
Sources
- Biology External Assessment, QCAA, 2025. 12 papers, 2020 to 2025, covering 230 questions and 556 marks. Listed individually in the table at the top of this guide. Dot-point numbering follows the current QCAA Biology syllabus.
Syllabus and assessment material referenced in this guide is © State of Queensland (Queensland Curriculum and Assessment Authority), licensed under CC BY 4.0. See our QCAA licensing notice. AusGrader is an independent study tool and is not affiliated with, endorsed by, or operated by the QCAA.
Keep reading
Practise what you just read
Work through real QCAA Biology questions and get your written answers marked against the official criteria, instantly.