Verbatim quotes from 4 official Cambridge examiner reports (2023–2025). Every quote is attributable to a specific paper and session — these are the things Cambridge markers flag year after year.

Describing antibiotic resistance using Lamarckism…

Very few candidates could give a coherent description of how antibiotic use has led to the spread of antibiotic-resistant bacteria. Answers often invoked Lamarckism by stating the antibiotics cause a change in the bacteria and that this change is inherited.

— Cambridge examiner, 5090 Paper 2/21, May/June 2023

Confusing global warming with ozone depletion

There is still some confusion between global warming and the destruction of the ozone layer. Very few appreciated that removing trees would remove minerals from the system.

— Cambridge examiner, 5090 Paper 2/21, May/June 2023

Describing osmosis using vague concentration language…

When explaining osmosis, the best answers referred to the differences in water potential inside and outside the cell. Candidates should be encouraged to use this terminology, as stated in the syllabus. If they describe concentration differences, it is often unclear whether they are referring to water or solute concentration.

— Cambridge examiner, 5090 Paper 2/21, May/June 2023

See how to avoid these in the Biology 5090 exam guide

Avoid these

Most Common Mistakes — Biology (5090)

Based on analysis of 4 official Cambridge examiner reports (2023, 2024, 2025). Avoid these errors to maximise your marks.

Describing antibiotic resistance using Lamarckism instead of natural selection

Paper 2 · Widespread in Paper 2, 2023

Confusing global warming with ozone depletion — attributing wrong causes and effects

Paper 1, Paper 2 · Common across Paper 1 and Paper 2, 2023

Describing osmosis using vague concentration language instead of water potential

Paper 2, Paper 3, Paper 4 · Recurring in Papers 2, 3, and 4, 2023

Explaining accommodation incorrectly — confusing iris circular muscles with ciliary muscles

Paper 2 · Common in Paper 2, 2023

Phototropism explained with incorrect auxin mechanism — auxin 'destroyed by light'

Paper 2 · Common in Paper 2, 2023

Focus your revision

Topics Students Struggle With Most

Antibiotic resistance by natural selection

Very few candidates could describe how antibiotic use leads to resistant bacteria. Answers invoked Lamarckism, confused immunity with resistance, and failed to mention alleles being passed to offspring.

Paper 2

Accommodation in the eye

Many candidates confused ciliary muscles with iris muscles. Despite being tested previously, the details of how ciliary muscles, suspensory ligaments, and lens shape interact were poorly understood.

Paper 2

Phototropism mechanism

Candidates incorrectly stated auxin is destroyed or burnt by light. Many linked auxin to growth without specifying cell elongation as the mechanism.

Paper 2

Phloem transport (translocation)

Candidates mentioned 'food' generically instead of naming sucrose and amino acids. Glucose and starch were frequently given as incorrect substances transported in phloem.

Paper 2

Data analysis and graph interpretation

Candidates described differences between groups instead of trends over time, confused percentages with numbers, and struggled to interpret limiting factor graphs correctly.

Paper 2, Paper 4

Eutrophication process

Candidates were too vague when describing oxygen balance and which organisms die. Many confused 'marine' with 'aquatic' and forgot that decomposers are living organisms.

Paper 2

Unit conversions (mm to micrometres, percentage change)

About two-thirds of candidates could not convert millimetres to micrometres. Many divided by the wrong value in percentage change calculations or forgot to multiply by 100.

Paper 2, Paper 3, Paper 4

Osmosis terminology

Candidates described concentration differences without specifying whether they meant water or solute concentration, losing marks for not using the syllabus term 'water potential'.

Paper 2, Paper 3, Paper 4

DNA function and protein synthesis

Candidates described DNA structure (double helix, base pairing) accurately but struggled to explain how the base sequence codes for the amino acid sequence and hence for specific proteins/enzymes. Many simply repeated the question by stating that DNA 'regulates cell function'.

Paper 2

Tissue fluid formation

Very few candidates could name liquids exchanged between capillaries and tissues or explain how tissue fluid is formed by pressure-driven filtration from blood plasma. Confusion with lymph and plasma terminology was common.

Paper 2

Dominant allele definition and genetic terminology

Candidates wrote vague answers such as 'the strongest allele' or 'the one with capital letters' rather than explaining that a dominant allele is expressed in the phenotype whenever present, including the heterozygous state. The distinction between gene, allele, genotype, and phenotype was frequently muddled.

Paper 2

Accuracy, reliability, and validity in experimental design

Candidates routinely conflated these three terms when justifying repeats or evaluating procedures. Repeats were incorrectly claimed to improve accuracy or remove errors, when they actually improve reliability and help identify anomalies.

Paper 3, Paper 4

About

Biology (5090) — Cambridge O Level Full Archive 2002–2026

This page contains all 753 available papers for Cambridge O Level Biology (5090) — 48 exam sessions from 2002 to 2026. Each session includes question papers, mark schemes, and where available, examiner reports and grade threshold documents. All files are free to download as PDF — no account required.

Cambridge O Level Biology (5090) is examined through multiple paper components. Question papers are available in two or three variants per session (v1, v2, v3) — each variant is sat in a different time zone but covers the same syllabus content and is equivalent in difficulty. The paper number in the filename indicates which component: for example, 5090_qp_12 is Paper 1, Variant 2.

Mark schemes for 5090 show the exact marking points accepted by Cambridge examiners. Many questions have multiple acceptable phrasings — look for 'accept', 'allow', and 'credit' in the mark scheme to understand the full range of valid responses. Examiner reports (where available) reveal the most common errors made by the cohort and what top-band answers looked like, making them essential reading before the actual exam.

The most effective way to use this archive is to attempt past papers under timed exam conditions, then analyse your mark scheme results by component. Track which paper components and question types you score lowest on — this tells you exactly where to focus revision. Grade threshold documents show the minimum mark needed for each grade in that specific session, which helps calibrate how your practice scores translate to actual grades.

Same subject

Biology 5090 at other levels

Cambridge IGCSE Biology

Subject code: 0610

Cambridge AS & A Level Biology

Subject code: 9700

FAQs

Questions, answered.

You can download all Cambridge Biology 5090 past papers right here on PapersDaddy. We have 48 exam sessions from 2002–2026 — including question papers, mark schemes, examiner reports, and grade thresholds for 5090. Click any session below to view and download PDFs.

Yes! Every Cambridge O Level Biology (5090) exam session includes the corresponding mark scheme alongside the question paper. Mark schemes show exactly how marks are allocated, helping you understand what examiners look for in top-scoring answers.

Start with recent 5090 papers (2025–2023) to understand current trends. Practice under timed conditions, then mark yourself using the mark scheme. Read examiner reports to learn common mistakes. For targeted revision, use Biology 5090 topical past papers to focus on specific topics.

We have Cambridge O Level Biology (5090) papers from May/June, October/November, and March sessions (where applicable), covering 2002–2026. That's 48 exam sessions in total.