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Cambridge O Level

Biology 5090

Living organisms from cell to ecosystem, with emphasis on human physiology, plants and inheritance.

Syllabus version: 2026–2028 syllabusChecked against the Cambridge syllabusExam year 2027 is covered by the 2026–2028 syllabus.
Subject review complete (21 Oct 2026). All 40 Biology questions were re-solved and checked against the syllabus and Cambridge mark-scheme conventions, and their auto-marking was tested with correct and incorrect answers: 27 approved as written, 13 corrected.

Weighting by paper. Some papers are alternatives (for example Core or Extended, or practical or alternative to practical), so the figures add up to more than 100%.

  • Paper 1 Multiple Choice30%
  • Paper 2 Theory50%
  • Paper 3 Practical Test20%
  • Paper 4 Alternative to Practical20%
Original questions40
Topics covered19/19
Papers4
Mock papers3

What is assessed

4 components. Question formats: multiple choice, short answer, structured, data response, practical, alternative to practical.

Paper 1 Multiple Choice
1 h40 marksWeighting 30%

Forty compulsory four-option multiple-choice items across the whole syllabus, testing AO1 and AO2.

What the paper looks like

Forty one-mark items with four options (A–D) in 1 hour, covering all 19 topics roughly in syllabus order. Many items are built on a diagram, table, key, graph or genetic diagram; a few need a quick calculation (magnification, percentage, energy transfer). Distractors are based on common confusions, so read every option before choosing.

Multiple choiceCalculator permitted; multiple-choice answer sheet
Checked against the Cambridge syllabus
Paper 2 Theory
1 h 45 min80 marksWeighting 50%

Compulsory short-answer and structured questions answered on the question paper, testing AO1 and AO2.

What the paper looks like

Six or seven compulsory structured questions totalling 80 marks in 1 hour 45 minutes, usually 10–17 marks each. Each question has a theme and mixes recall (State, Name, Identify) with data handling (graphs, tables, photomicrographs, percentage change, unit conversion) and Explain/Describe/Suggest parts of 2–4 marks; there is often a longer answer of about 6 marks that rewards several distinct, well-organised points.

Short answerStructuredData responseCalculator permitted
Checked against the Cambridge syllabus
Paper 3 Practical Test
1 h 30 min40 marksWeighting 20%

Compulsory laboratory-based questions testing AO3 experimental skills; taken as an alternative to Paper 4.

What the paper looks like

Usually three compulsory questions totalling 40 marks in 1 hour 30 minutes, carried out in the laboratory: food tests, enzyme or osmosis investigations, timing and measuring, recording results in a table with headings and units, drawing a specimen in pencil, magnification, plotting a graph or bar chart, and evaluating or planning an investigation.

PracticalLaboratory apparatus and materials set out in the Confidential Instructions; calculator permitted
Checked against the Cambridge syllabusNo questions for this paper yet
Paper 4 Alternative to Practical
1 h40 marksWeighting 20%

Compulsory written questions on the same experimental skills and contexts as Paper 3 (AO3); no experiments are carried out.

What the paper looks like

Usually three compulsory questions totalling 40 marks in 1 hour, on the same experimental contexts as Paper 3 but with results supplied. Expect reading scales from diagrams, completing tables (quantity / unit headings, consistent decimal places), plotting graphs with the independent variable on the x-axis, drawing and measuring from photographs, identifying variables and anomalies, suggesting controls and improvements, and planning short investigations.

Alternative to practicalCalculator permitted
Checked against the Cambridge syllabus

Assessment overview

From the 2026–2028 syllabus. Checked against the Cambridge syllabus

All candidates
Paper 1Paper 2Paper 3Paper 4
Paper 1 and Paper 2, plus either Paper 3 (Practical Test) or Paper 4 (Alternative to Practical); grades A* to E available.
Assessment objectiveO Level weighting
AO1 Knowledge with understanding50%
AO2 Handling information and problem-solving30%
AO3 Experimental skills and investigations20%
Changes in this syllabus version
  • No significant changes affecting teaching compared with the 2023–2025 syllabus: the same 19 topics, three papers taken per candidate, timings, marks and weightings.
  • Version 2 (December 2024) clarified that Paper 2 lasts 1 hour 45 minutes and made a minor typographical correction to the metric units list.
  • Version 3 (January 2025) amended the wording of the command words table; version 4 (December 2025) updated a weblink.
  • Textbooks endorsed for examination from 2023 remain suitable.
Command words used in Biology papers (18)
Assess
make an informed judgement
Calculate
work out an answer from the facts, figures or information given
Comment
give an opinion based on evidence
Compare
say how things are similar and/or different
Contrast
say how things are different
Define
give the exact meaning
Describe
state the points of a topic or give its characteristics and main features
Determine
reach an answer using the information provided
Discuss
write about an issue or topic in depth, in an organised way
Evaluate
judge or work out the quality, importance, amount or value of something
Explain
give reasons or purposes, make relationships clear, say why and/or how, with supporting evidence
Give
produce an answer from a source provided or from memory
Identify
name, select or recognise
Outline
set out the main points briefly
Predict
say what may happen, using the information available
Sketch
make a simple freehand drawing showing the key features, with sensible proportions
State
express clearly and briefly
Suggest
apply knowledge to an unfamiliar situation where several answers are valid, putting forward ideas
Examiner guidance from recent reports (14)
Cells. Magnification questions are often lost on units, not on the formula. Convert the image size and the actual size to the same unit first (1 mm = 1000 µm), and give magnification as a number with × and no unit.
Classification. Define a species precisely: organisms that can reproduce to produce fertile offspring. “Organisms that look alike” or “share features” earns nothing. In a binomial name the first word is the genus and the second the species.
Movement into and out of cells. Explain osmosis using water potential and a partially permeable membrane, and say which way the water moves. Write “water molecules”, never “molecules of solution”. In plasmolysis it is the membrane and cytoplasm that pull away from the cell wall.
Biological molecules. Food-test answers need the reagent, any heating (Benedict’s needs a hot water bath) and the colour change from start to finish, e.g. blue to brick red. A negative result is recorded as the reagent’s own colour, not “no change” on its own.
Enzymes. At high temperature or the wrong pH, say the active site changes shape so the substrate no longer fits and fewer enzyme–substrate complexes form. Enzymes are denatured, not “killed”. Below the optimum, refer to lower kinetic energy and fewer effective collisions.
Plant nutrition. A limiting factor is the factor in shortest supply: if raising light intensity no longer raises the rate, light is no longer limiting. Read the graph carefully before naming the factor, and link magnesium to chlorophyll and nitrate to amino acids and proteins.
Transport in flowering plants. Transpiration is evaporation from the surfaces of mesophyll cells followed by diffusion of water vapour out through the stomata. Wind and low humidity work by keeping the water vapour concentration gradient steep; say so explicitly.
Human nutrition. Bile emulsifies fat into small droplets to increase the surface area for lipase; it does not digest or break down fat chemically. Maltose is digested by maltase, not by amylase, and fibre is not digested at all: it is egested.
Human gas exchange. In breathing questions, link each muscle action to the volume change and then the pressure change: volume of thorax increases, pressure falls below atmospheric pressure, air moves in. Do not mix up goblet cells (make mucus) and ciliated cells (move mucus).
Transport in humans. When explaining tissue fluid, say that plasma is forced out of capillaries under pressure. For the heart, the left ventricle wall is thicker because it pumps blood at higher pressure all round the body, not because it “pumps more blood”.
Excretion. Do not confuse urea with urine. Give the direction of movement in the nephron: glucose is filtered from the glomerulus into the Bowman’s capsule and then all of it is reabsorbed back into the blood. Proteins stay in the blood because they are too large to be filtered.
Coordination and response in plants. In phototropism, light is detected at the shoot tip and auxin moves to the shaded side; it is not destroyed by light. More auxin on the shaded side causes more cell elongation there, so the shoot bends towards the light.
Disease and immunity. Antibodies are specific because their shape is complementary to one antigen. A faster, larger response to a second exposure is due to memory cells made after the first exposure; passive immunity gives no memory cells.
Relationships of organisms with one another and with the environment. Longer ecology answers need cause and consequence, not general statements. For eutrophication, give the sequence in order: more nitrate, algae grow, algae die, decomposers increase, aerobic respiration by decomposers uses up dissolved oxygen, fish die. Plan before writing to avoid repetition.

Topic map

Practice types

Free sample questions

Which structures are found in both a bacterial cell and a palisade mesophyll cell?
Which structures are found in both a bacterial cell and a palisade mesophyll cell?
  1. cell wall, cell membrane and ribosomes
  2. cell wall, nucleus and ribosomes
  3. chloroplasts, cell membrane and cytoplasm
  4. plasmids, cytoplasm and cell wall

Answer: A. cell wall, cell membrane and ribosomes

Both cells have a cell wall (cellulose in the plant cell), a cell membrane and ribosomes for protein synthesis. Bacteria have no nucleus and no chloroplasts, and plasmids are found in bacteria but not in plant cells.

The scientific name of the lion is Panthera leo and the scientific name of the tiger is Panthera tigris. What…
The scientific name of the lion is Panthera leo and the scientific name of the tiger is Panthera tigris.
What do these names show?
  1. They belong to the same species but to different genera.
  2. They can reproduce together to produce fertile offspring.
  3. They belong to the same genus but are different species.
  4. They belong to different genera and different species.

Answer: C. They belong to the same genus but are different species.

In the binomial system the first part of the name is the genus and the second is the species. Both animals are in the genus Panthera but have different species names, so they are different species. The names alone give no information about interbreeding.

FAQs

Are these official 5090 past-paper questions?

No. They are original questions written to match the Biology syllabus topics. Official past papers are available to schools through Cambridge.

Why choose an exam year?

Cambridge updates syllabuses periodically. Your exam year selects the matching configuration so topics and components follow the right version.

Is a calculator allowed?

In this configuration a scientific calculator is permitted for the listed papers. Check your syllabus for the exact rule.