KCSE Biology Paper 2 (231/2): Revision Guide and Questions

Last reviewed: 31 October 2026

Updated October 2026. KCSE Biology Paper 2 (231/2, Biology Paper 2 (Theory)) is a 2 hours paper. Section A has structured questions (about 40 marks); Section B has a compulsory graph question and one essay from a choice of two (about 40 marks). On the KNEC 2026 timetable it is on Thursday 12 November 2026, 8.00 to 10.00 am. Below: what the paper covers, how to answer for marks, original practice questions with answers, and a timed KCSE Biology Paper 2 challenge you can try free.

What is in KCSE Biology Paper 2?

Section A has structured questions (about 40 marks); Section B has a compulsory graph question and one essay from a choice of two (about 40 marks). Always follow the instructions printed on your own paper; layouts can change.

Topics that come up most in Biology Paper 2

• Genetics and evolution
• Reproduction and growth
• Response and coordination
• Support and movement
• Ecology data and graph work

How to answer Biology Paper 2 for marks

1. Practise plotting graphs from data: it is a compulsory question.
2. In essays, make many relevant points; marks are per point.
3. Use genetic diagrams with gametes clearly shown.
4. Read every question twice and underline the command word (state, explain, describe, calculate).
5. Budget time by marks: roughly one minute per mark, plus checking time.

Topic weighting: where the marks are in Biology Paper 2

Section A structured questions and Section B (graph plus one essay) carry about equal marks. Genetics and ecology data questions are common choices.

Common mistakes in KCSE Biology Paper 2

• Genetic crosses without showing gametes
• Graphs with the axes reversed or no title
• Essays written as short notes
• Choosing the essay you know least because it looks shorter

Examiner-style tips for Biology Paper 2

• Use a Punnett square and state the ratio at the end.
• In graph interpretation, quote values from your graph.
• Plan essays as a list of points first, then write each as a sentence.

KCSE Biology Paper 2 questions and answers (practice)

These are original practice questions written for revision, not KNEC papers.

Question 1

A heterozygous tall pea plant (Tt) is crossed with a short plant (tt). Give the ratio of offspring.

Answer: 1 tall : 1 short.

Question 2

Name the hormone that controls blood sugar after a meal.

Answer: Insulin.

Question 3

What is a test cross?

Answer: Crossing an organism showing the dominant trait with a homozygous recessive one to find its genotype.

Question 4

Give two functions of the skeleton in mammals.

Answer: Support and protection of internal organs.

Question 5

Name the hormone that causes fruit ripening.

Answer: Ethylene.

Biology Paper 2 revision checklist

Tick each line only when you can do it from memory, under time:

• I can answer an exam-style question on genetics and evolution without notes.
• I can answer an exam-style question on reproduction and growth without notes.
• I can answer an exam-style question on response and coordination without notes.
• I can answer an exam-style question on support and movement without notes.
• I can answer an exam-style question on ecology data and graph work without notes.
• I have done at least one full 2 hours practice paper and marked it.
• I have listed my last five mistakes and redone them correctly.

On the day of Biology Paper 2

Thursday 12 November 2026, 8.00 to 10.00 am. Be seated 15 minutes early. Carry blue or black pens, a pencil, a ruler and a rubber, a mathematical set and an approved non-programmable calculator. Read the whole paper in the first five minutes and mark the questions you will answer first. Leave the last ten minutes to check your answers and that your index number is on every page you hand in.

Three-day plan for Biology Paper 2

Practise Biology Paper 2 online

The KCSE Biology Paper 2 challenge gives timed questions with a score, a leaderboard rank and a share card. For full papers with worked answers see KCSE practice papers, the KCSE Biology revision quiz and this related guide. Check dates in the KCSE 2026 timetable and use the last-minute revision plan.

How this guide differs from past-paper sites

The top Google results for KCSE Biology Paper 2 are mostly PDF downloads of old papers and marking schemes. Those are useful, but they rarely explain where the marks sit, what candidates get wrong or how to practise under time. This guide adds that, with original questions and a timed online challenge with instant marking.

Frequently asked questions

Is there a graph in KCSE Biology Paper 2?

Yes, recent papers include a compulsory question with data to plot and interpret.

Where can I get the KCSE Biology Paper 2 marking scheme?

Official marking schemes are not published by KNEC for sale. Use practice papers with worked answers and the answers on this page, and be wary of anyone selling ‘marking schemes’ for the coming exam.

Are KCSE Biology Paper 2 leaked papers real?

No. Papers sold online before the exam are scams, and holding them is an exam irregularity that can lead to cancelled results (see KCSE exam rules).

How long is KCSE Biology Paper 2?

2 hours on the 2026 timetable.

Can I download the KCSE Biology Paper 2 2025 PDF here?

We do not host KNEC papers. Practise with original papers in the same format, with worked answers, in KCSE practice papers; schools keep past KNEC papers for their candidates.

Is there a KCSE Biology Paper 2 prediction for 2026?

Prediction papers are teachers’ practice papers, not the real exam. Use them like any past paper and focus on the topics listed above.

Want marked practice? Try the first questions free. A Day Pass (KSh 20) or Weekly Pass unlocks full papers with worked answers, paid once by M-Pesa, no auto-renewal. See all passes.

Keep revising with these: KCSE 2026 Paper-by-Paper Revision Challenges.