Hello again, future biologists! 👋 If you’ve been revising hard for Paper 1, well done! But now it’s time to shift gears and look at Paper 2 (Biological Diversity) and Paper 3 (Unified Biology).
We know exam season is a marathon, not a sprint. It’s completely normal to feel a bit frazzled right now 🤯. Please remember to be kind to yourself. A walk in the park 🌳, a good night's sleep 😴, or a chat with a friend can do wonders for your focus. Your mental health matters just as much as your grades!
⚠️ Important Reminder
Before we dive into the predictions, please remember to review the entire specification. As much as we’d love to have a crystal ball 🔮, we haven't seen the 2026 exams. These predictions are based on careful analysis of past trends, but anything in the OCR-A (H420) specification could appear. Treat this list as your focus areas, not the only things you study!
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📚 Revision Guide: Top Predictions for 2026 (Paper 2 & 3)
MCQs on Any Topic! 🎲
Paper 2 Section A is always multiple choice. These questions can pick apart tiny details from the specification, so keep your knowledge sharp across topics 1, 2, 4 and 6!
🌿 Biological Diversity & Analysis (Modules 4 & 6)
Immune Response & Antibodies 🛡️
Know the difference between non-specific defences (skin, inflammation) and the specific immune response (T and B lymphocytes). You must be able to draw and label an antibody (variable region, constant region, hinge region, disulfide bridges). Understand opsonisation, agglutination, and how vaccines provide active immunity.
Biodiversity & Simpson's Index 🦜
Define biodiversity (habitat, species, and genetic). Be ready to calculate Simpson's Index of Diversity, a high value means a stable ecosystem.
Succession 🌲
Describe the process from pioneer species colonising bare rock (primary succession) to the formation of a climax community. Understand how species alter the abiotic conditions to make the environment less hostile for new species.
Classification 🦁
Know the taxonomic hierarchy (Kingdom, Phylum, Class, Order, Family, Genus, Species). Be familiar with the Five Kingdoms vs. the Three Domains (Archaea, Bacteria, Eukarya) and the evidence used in classification (cytochrome c, DNA sequences).
Genetic Diversity 🧬
How do we assess genetic diversity? Look at the proportion of polymorphic gene loci
Genetic Inheritance & Hardy-Weinberg 🧮
This is a big one! Be comfortable with monohybrid and dihybrid crosses, codominance, epistasis and sex linkage. You must know how to use the Hardy-Weinberg equations (p + q = 1 and p2 + 2pq + q2 = 1) to calculate allele frequencies. Remember the assumptions (large population, no migration, etc.).
Speciation 🌋
How do new species form? Compare allopatric speciation (geographical isolation) and sympatric speciation (reproductive isolation within the same area).
Cellular Control ⚙️
How are genes regulated? Revise the lac operon in E. coli (repressor protein, operator, promoter). Understand homeobox genes (Hox genes) in the control of body plan development and how apoptosis shapes tissues (like removing webbing between fingers).
Gel Electrophoresis ⚡
A key practical technique. Know how DNA fragments are separated by size using an electric current (DNA is negatively charged so moves to the anode).
Biotechnology (Food Production) 🧀
The use of microorganisms! Explain the benefits and risks of using microorganisms in industrial processes including food production.
Immobilised Enzymes 🔒
Why do we use them? They are more stable and the product isn't contaminated with the enzyme. Know the methods: adsorption, covalent bonding, entrapment, and membrane separation.
Bacterial Growth & Aseptic Technique 🧫
The standard growth curve: lag phase, log phase, stationary phase, death phase. Be able to explain aseptic techniques to prevent contamination during practicals (flaming necks of bottles, working near a Bunsen flame).
🧬 Core Topics (Likely in Any/All Papers)
These topics are fundamental and often bridge the gap between Paper 1 and Paper 2, or appear in the Unified Paper 3.
ATP Structure and Function 🔋
The universal energy currency. Adenine + Ribose + 3 Phosphates. Hydrolysis releases energy for metabolism.
Enzymes & Cofactors 🧩
Induced-fit model. Factors affecting rate (Temperature, pH). Cofactors (inorganic ions), Coenzymes (organic, e.g., NAD), and Prosthetic groups (tightly bound, e.g., Zn²⁺ in carbonic anhydrase).
Protein Synthesis 🏗️
transcription (nucleus) → mRNA → translation (ribosome/RER) → polypeptide.
Lipid Structure 🧈
Triglycerides (glycerol + 3 fatty acids) vs Phospholipids. Ester bonds. Saturated vs Unsaturated.
Mitosis & Cell Cycle 🔄
Interphase (G1, S, G2), Mitosis (PMAT), Cytokinesis. Role in growth and repair.
Meiosis 🎲
Production of haploid gametes. Sources of variation: Crossing over (Prophase I) and Independent Assortment.
Microscopes 🔬
Magnification vs Resolution. Light microscopes vs Electron microscopes (TEM/SEM). Calibration using a stage micrometer.
DNA Replication 🧬
Semi-conservative. Helicase unzips; Polymerase joins nucleotides. Watson and Crick model.
Cell Structure 🦠
Eukaryotic organelles (Golgi, Lysosomes, RER, SER, Mitochondria). Prokaryotic features (Plasmids, loop of DNA, cell wall).
Food Tests 🧪
Biuret (protein), Benedict's (sugars), Iodine (starch), Emulsion (lipids).
📝 Exam Structure Breakdown
Paper 2: Biological Diversity 🌿
Total Marks: 100
Time: 2 hours 15 minutes
Content: Focuses on Modules 1, 2, 4, and 6.
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Format:
Section A: 15 marks of Multiple Choice Questions (MCQs).
Section B: 85 marks of short answer and extended response questions.
Paper 3: Unified Biology 🌎
Total Marks: 70
Time: 1 hour 30 minutes
Content: All Modules (1 to 6). This paper tests your ability to make links between different topics (e.g., enzymes and evolution).
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Format:
Section A: Structured questions covering the whole specification.
Section B: Practical application questions (analysing data, experimental design, evaluating methods).