OCR A Level Biology B (H422) Past Papers 2026

Fundamentals of Biology

Duration: 2h 15m

Scientific Literacy in Biology

Duration: 2h 15m

Practical Skills in Biology

Duration: 1h 30m

Common Practical Assessment Criteria (CPAC)

Duration: Pass/fail — assessed throughout the course by the centre

Immunity — clonal selection, clonal expansion, and differentiation of lymphocytes

H422/02 2023 Q1(d) LoR: candidates limited to Level 2 due to lack of scientific detail or omission of clonal selection, clonal expansion, or differentiation. Misconception box explicitly flags that clonal expansion (mitotic proliferation of activated lymphocytes) and differentiation (forming plasma cells and memory cells) are confused as a single process. Many candidates also failed to link antigen-presenting cells at the start of the primary immune response.

H422/02

Water potential — correct terminology, direction of movement, and osmosis vs diffusion

H422/02 2024 Q3(b)(ii): candidates incorrectly stated water moved from cytosol to tissue fluid (reversed direction), or used 'concentration of water' instead of 'water potential'. Assessment for learning note explicitly states: 'Candidates at this level should be encouraged in the use of the correct terminology. Some candidates still describe water potential in terms of concentration of water.'

H422/02

Light-dependent and light-independent reactions — NADP vs NAD, and GP to TP pathway

H422/03 2023 Q2(c)(i): reduced NAD written instead of reduced NADP in light-dependent reactions — flagged as a common misconception. H422/02 2024 Q7(c): many candidates could not state that glycerol for triglyceride synthesis comes from TP, or that GP is converted to acetyl CoA and then to fatty acids. Candidates could order molecules but could not explain the biochemical transformations between them.

H422/02, H422/03

Statistical tests — degrees of freedom, p-value interpretation, and null hypothesis language

H422/03 2023 Q4(b)(ii): many candidates unable to deduce correct degrees of freedom; several drew incorrect conclusions and rejected the null hypothesis when they should have accepted it. H422/02 2024 Q4(c)(ii): most candidates could not reference statistical significance correctly — they interpreted p as a critical value rather than a probability. Correct comparison: p 0.002 is much less than 0.05 (significant); p 0.515 is much greater than 0.05 (not significant).

H422/02, H422/03

Stem cell potency — distinguishing totipotent, pluripotent, and multipotent in context

H422/03 2023 Q1(c): despite knowing the terms, many candidates still struggle to distinguish between pluripotent and multipotent in context — this had also been flagged in the H422/01 June 2022 report. Candidates correctly identified totipotent but confused which stem cell types are present in adult vs embryo. Many also used hybrid tick-and-cross answers in tables, which examiners do not credit.

H422/03

Control variables in practical investigations — explaining why each variable must be controlled, not just naming it

H422/02 2024 Q3(c)(i): most candidates identified a control variable (e.g. temperature) but few went on to explain why it should be controlled, limiting them to 1 mark. H422/03 2023 Q2(b)(i): many candidates wrote 'same light intensity' and 'same volume of indicator' without explaining why these were necessary. Naming the variable earns the first mark; explaining the biological reason for controlling it earns the second.

H422/02, H422/03

Homeostasis and diabetes — defining the effector response in Type 2 and gestational diabetes

H422/01 2023 Q35(c)(iii): most candidates incorrectly described gestational diabetes in terms of beta cells under-producing insulin (a Type 1 pattern). The misconception note makes clear that Type 2 and gestational diabetes are characterised by effector cells becoming less responsive to insulin, not by reduced insulin production.

H422/01

Ecology — transects vs random sampling, and calculating Simpson's Diversity Index correctly

H422/03 2024 Q5(a)(ii): few candidates gained full marks; many described random sampling rather than a transect across the wetland gradient. Using random quadrats could result in all samples from one area — a transect ensures sampling across the gradient. H422/03 2024 Q5(b)(i): common error was giving the sum of n(n-1)/N(N-1) values as the final answer without subtracting from 1 to calculate D.

H422/03