Edexcel GCSE Biology Paper 2 practice questions

What is on Paper 2?

• Paper 2 covers bioenergetics, homeostasis, inheritance and ecosystems.
• It is a written paper of 1 hour 45 minutes, worth 100 marks — 50% of the GCSE.
• Questions are a mix of multiple choice, short answer, calculations and extended writing.
• Core practicals and maths skills from across the course can be examined on either paper.

Paper 2 practice questions with answers

14 original questions across the 7 Paper 2 topics. Try each one before reading the answer.

1. Photosynthesis

   1. Write the word equation for photosynthesis.

   Answer: Carbon dioxide + water → glucose + oxygen

   Light and chlorophyll go above the arrow, not in the reactants.

2. Photosynthesis

   2. A graph of rate vs light intensity levels off. What does this suggest?

   • • Light is still limiting
   • • Another factor such as CO₂ or temperature is now limiting
   • • The plant has died
   • • Respiration has stopped

   Answer: Another factor such as CO₂ or temperature is now limiting

   A plateau means light is no longer the limiting factor.

3. Respiration and exercise

   3. What is produced by anaerobic respiration in human muscle?

   • • Ethanol
   • • Lactic acid
   • • Carbon dioxide only
   • • Water

   Answer: Lactic acid

   Yeast makes ethanol; muscle makes lactic acid.

4. Respiration and exercise

   4. Explain why breathing rate stays high after exercise finishes.

   Answer: To repay the oxygen debt — extra oxygen is needed to oxidise the lactic acid that built up.

   Mention oxygen debt and lactic acid.

5. The nervous system and reflexes

   5. Put the reflex arc in order.

   Answer: Stimulus → receptor → sensory neurone → relay neurone → motor neurone → effector → response

   Learn this sequence word for word.

6. The nervous system and reflexes

   6. Why are reflex actions fast?

   • • They involve fewer synapses and skip conscious brain processing
   • • The impulse travels as light
   • • They use hormones
   • • They only happen in the hand

   Answer: They involve fewer synapses and skip conscious brain processing

   Speed protects the body from harm.

7. Hormones and blood glucose

   7. Which organ monitors and controls blood glucose concentration?

   • • Liver
   • • Pancreas
   • • Kidney
   • • Pituitary

   Answer: Pancreas

   It detects the level and releases insulin or glucagon.

8. Hormones and blood glucose

   8. Describe what happens when blood glucose rises after a meal.

   Answer: The pancreas releases insulin; glucose moves into liver and muscle cells and is stored as glycogen, lowering blood glucose.

   Insulin → storage as glycogen → level falls.

9. Genetics and inheritance

   9. Two heterozygous parents (Bb × Bb) have a child. What is the probability of a recessive phenotype?

   • • 0%
   • • 25%
   • • 50%
   • • 75%

   Answer: 25%

   Only bb shows the recessive phenotype — 1 in 4.

10. Genetics and inheritance

    10. Define phenotype.

    Answer: The physical characteristics an organism shows, resulting from its genotype and environment.

    Genotype = alleles; phenotype = what you see.

11. Variation, evolution and selection

    11. Explain how antibiotic-resistant bacteria arise.

    Answer: A random mutation makes some bacteria resistant; the antibiotic kills the rest, the resistant ones survive, reproduce and pass on the allele.

    Mutation → survival → reproduction → spread.

12. Variation, evolution and selection

    12. Which is a disadvantage of selective breeding?

    • • Reduced genetic variation and more inherited disease
    • • It is illegal
    • • It slows plant growth
    • • It causes mutations in humans

    Answer: Reduced genetic variation and more inherited disease

    Inbreeding reduces the gene pool.

13. Ecosystems and adaptations

    13. Which of these is an abiotic factor?

    • • Predators
    • • Light intensity
    • • Disease
    • • Competition

    Answer: Light intensity

    Abiotic = non-living.

14. Ecosystems and adaptations

    14. Explain why removing a predator can reduce biodiversity.

    Answer: Prey numbers rise, they over-consume their food source, so other species decline or die out.

    Follow the chain through the food web.

Where Paper 2 marks are usually lost

• Stating a genotype ratio without drawing the Punnett square that supports it.
• Writing 'the body fixes it' instead of naming the hormone and the direction of change in homeostasis questions.
• Giving one adaptation when 'explain' needs the adaptation plus its survival advantage.
• Misreading log scales or axes on ecology data questions.
• Confusing aerobic and anaerobic respiration products.

How to pick up the extended-answer marks

• Spend the first 30 seconds underlining the command word — 'describe', 'explain' and 'evaluate' are marked differently.
• Plan one point per mark, each carrying a scientific term and a consequence. Short linked sentences beat one long paragraph.
• For 'evaluate' questions, include a benefit, a drawback and a judgement sentence at the end.
• For required practical questions, name the control variable and how the result was measured — method detail is where the marks sit.

Timing that works under pressure

• Work at roughly one mark per minute so you keep spare time for checking at the end.
• Bank the short recall questions first, then return to the longer answers with your remaining time.
• If a question stalls for more than two minutes, write down what you know and move on — partial marks still count.
• Leave five minutes to check units, significant figures and whether any question part was skipped over a page break.

Revise each Paper 2 topic

• Photosynthesis (76 questions)
• Respiration and exercise (76 questions)
• The nervous system and reflexes (76 questions)
• Hormones and blood glucose (76 questions)
• Genetics and inheritance (77 questions)
• Variation, evolution and selection (76 questions)
• Ecosystems and adaptations (76 questions)

Edexcel Biology Paper 2 FAQs

What topics are on Edexcel GCSE Biology Paper 2?

Paper 2 assesses bioenergetics, homeostasis and response, inheritance, evolution and ecosystems. Required practicals and data skills linked to these topics can also be examined.

How long is Edexcel GCSE Biology Paper 2?

It is a 1 hour 45 minute written exam worth 100 marks, which is 50% of the GCSE. Working at about one mark per minute leaves time to check your answers.

How should I revise for Biology Paper 2?

Practise answering questions rather than rereading notes. Short daily sets of five questions per topic, marked straight away, expose weak areas faster than a long passive revision session.