GuidesBiologyPaper 2 · last-minute revision
3 days to go

GCSE Biology OCR A Paper 2: last-minute revision

Three days left. Paper 2 covers B4 to B6: ecosystems, genetics and global health challenges, plus 15 multiple choice questions that can draw on B1-B3 material too. Disease, immunity and evolution carry the most marks here.

OCR Gateway Science A, J247
The plan

Your 3-day plan

One focus per day, building to a timed run. Work it in order.

3
3 days to go

Community level systems (B4): ecosystems and decomposition

  • Revise ecosystems: food chains, food webs, and how to construct and interpret a pyramid of biomass. Know why energy is lost between trophic levels and why food chains rarely have more than five links.
  • Go through competition and adaptation, including predator-prey population cycles, then revise the carbon cycle so you can redraw it from memory.
  • Learn the role of decomposers and the factors that affect the rate of decomposition, including temperature, oxygen and moisture.
2
2 days to go

Genes, inheritance and selection (B5)

  • Practise Punnett square questions until predicting genotype and phenotype ratios is automatic. Know the difference between a gene, an allele and a chromosome.
  • Revise Darwin's theory of evolution by natural selection and apply it to an unfamiliar organism using the same three steps every time: variation, survival advantage, reproduction.
  • Go through antibiotic resistance as a real-world example of natural selection, since it links B5 directly to the disease content in B6.
1
1 day to go

Global challenges (B6): disease, vaccination and food security, plus a full past paper

  • Revise how the body defends against pathogens: physical barriers, phagocytosis, and the specific immune response with lymphocytes and antibodies. Learn how vaccination works and why herd immunity matters.
  • Go through the heart and circulatory system again in the context of cardiovascular disease and risk factors, then revise plant disease identification and defences.
  • Sit one full past paper under timed conditions and mark it against the scheme. Remember the multiple choice section can still test B1-B3 content, so don't assume this paper is only B4-B6.
Priority order

The topics that come up most

Ranked from analysed past papers. Start at the top: if you run out of time, you will have covered the most-tested ground.

1

Ecosystems, food webs and pyramids of biomass

Constructing and interpreting food webs and biomass pyramids is core B4 content that appears in almost every paper, often combined with an energy transfer calculation.

2

Genetic inheritance and Punnett squares

Genetic diagrams are a guaranteed calculation-style question on this paper. Practise them until working out ratios is automatic.

3

Evolution and natural selection

Almost always tested using an unfamiliar example organism. You need to apply Darwin's theory step by step to the specific example given, not just define natural selection.

4

Pathogens, disease and vaccination

How the body defends itself against pathogens, and how vaccination triggers memory cell production, regularly appears as an extended response worth several marks in the B6 global challenges content.

5

Vaccination and herd immunity

Vaccine mechanism and herd immunity questions are a reliable source of marks, and often link into an evaluate-style question about vaccination programmes.

6

Carbon cycle and decomposition

Redrawing the carbon cycle from memory and explaining the role of decomposers and the factors affecting decay rate are dependable sources of marks that are easy to lose through vague answers.

7

Biodiversity and human impacts

Human impacts on biodiversity, including habitat destruction and pollution, come up as both recall and evaluate-style questions on this paper.

8

Heart, circulation and cardiovascular disease

Applied heart and circulation questions in a disease-risk context are a signature OCR A question style that reappears across multiple papers.

Your Knowledge Organisers

PrepWise has a one-page Knowledge Organiser for every topic above. In your final 3 days, use them the same way each time: cover the page, try to recall everything from memory, uncover and check what you missed, then repeat that topic again tomorrow.

Open the Biology Knowledge Organisers
Cheat sheet

Exam technique

Rules specific to Paper 2. On this paper, structure earns as many marks as knowledge.

1

The multiple choice section is not limited to B4-B6

OCR A explicitly assesses B1-B3 content synoptically on this paper alongside B4-B6. Don't assume cell biology, respiration or the nervous system are 'done' just because you sat Paper 1 already; keep a quick recap of Paper 1 topics in your final 3 days.

2

Biomass pyramid and food web questions reward precise vocabulary

Use 'producer', 'primary consumer', 'trophic level' and 'biomass' correctly and consistently. A vague answer like 'the energy goes down' loses marks compared with 'energy is lost as heat through respiration at each trophic level'.

3

Apply natural selection to the exact organism in the question

Your answer must reference that specific organism's variation and advantage, in order: variation exists, it gives a survival advantage, more individuals with that allele survive to reproduce. A generic definition alone loses marks.

4

The Level of Response question can be anywhere on this paper

The single asterisked 6-mark question rotates topic every year and has covered ecology, immunity and genetics in past series. Write in connected paragraphs and cover the process logically rather than as disconnected bullet points.

Avoid these

5 mistakes that cost marks

The errors examiners see most on this paper. Each one is an easy mark you already know how to keep.

Forgetting energy is lost at every trophic level, not just from producer to consumerEnergy is lost through respiration, movement and heat at every single step of a food chain, which is why food chains rarely have more than four or five links. State this explicitly rather than assuming the examiner will infer it.

Writing 'survival of the fittest' as the whole answer on natural selectionThat phrase alone earns no marks. You need the full chain: variation exists in a population, some variants have an advantage, those individuals are more likely to survive and reproduce, so the allele becomes more common over generations.

Confusing vaccination with treatmentA vaccine prevents disease by training the immune system to produce antibodies and memory cells before infection happens. It doesn't cure an existing infection. Keep prevention and treatment language separate in your answer.

Saying antibiotics work on virusesAntibiotics only work on bacteria because they target processes bacterial cells have that human and viral cells don't. Viruses reproduce inside host cells, so antibiotics have nothing to target.

Not explaining WHY decomposition speeds up, only that it doesWarmer temperature, more oxygen and more moisture all increase the activity of decomposer microorganisms, which is why decay rate increases. State the mechanism, not just the trend.

Exam day

The morning of the exam

The 60 minutes before you walk in. Review what you know and settle your nerves.

  • Redraw the carbon cycle from memory one final time.
  • Say the natural selection chain out loud once: variation, advantage, survival, reproduction, more common allele.
  • Check you have a black pen, a spare pen, and a ruler for drawing genetic diagrams.
  • Do not attempt new topics this morning. Only review what you already know.
  • Remind yourself that the multiple choice section can still test B1-B3, so don't skip your Paper 1 topics entirely.
  • Eat something before you go in. A blood glucose crash mid-exam is avoidable.

Now test yourself

Reading this plan is not the same as being able to do it. Answer exam-style Biology questions in PrepWise, get them marked in seconds, and find the gaps while you still have time to fix them.

Practise Biology questions

Start the 3-day plan now

Open the Biology Knowledge Organisers, quiz every priority topic and walk in ready. Free during alpha.

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