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IGCSEBiology
Trial Class

Original practice · 5 questions · 15 marks · about 17 minutes

Nervous System and Reflexes Practice Questions

Biology editorial review is supported by the named review panel. Reviewer participation may vary by guide. Checked against Cambridge IGCSE Biology 0610 (2026–2028); last reviewed August 2026.

These questions test your understanding of how the nervous system detects stimuli, transmits impulses, and produces rapid reflex responses.

Before you open the answers

  • Attempt every question without notes.
  • Show working for calculations and write complete biological statements.
  • Use the suggested time as a guide, not a strict limit on the first attempt.

These are original practice questions. They do not reproduce an official Cambridge paper or official mark scheme.

  1. Question 1

    Paper 4 Both 4 marks Difficulty 3/5

    Describe the pathway of a reflex arc, naming the five components in the correct order.

    Show model answer and marking guidance
    1. Receptor (detects the stimulus).
    2. Sensory neurone (transmits impulse from receptor to CNS).
    3. Relay neurone in the spinal cord / CNS (connects sensory to motor).
    4. Motor neurone (transmits impulse from CNS to effector).
    5. Effector: muscle (contracts) or gland (secretes).

  2. Question 2

    Paper 4 Extended 3 marks Difficulty 3/5

    Explain why reflex actions are important for survival.

    Show model answer and marking guidance
    1. Reflex actions are fast / automatic: they do not require conscious thought.
    2. They protect the body from harm: e.g. Pulling hand away from a hot surface.
    3. Speed of response reduces the chance of injury.

  3. Question 3

    Paper 4 Extended 3 marks Difficulty 4/5

    Describe how a nerve impulse is transmitted across a synapse.

    Show model answer and marking guidance
    1. An electrical impulse arrives at the end of the presynaptic neurone.
    2. Chemical transmitter substance (neurotransmitter) is released into the synaptic gap.
    3. Neurotransmitter diffuses across the gap and binds to receptors on the postsynaptic neurone, triggering a new impulse.

  4. Question 4

    Paper 2 Core 2 marks Difficulty 1/5

    Define the term "stimulus" and give one example.

    Show model answer and marking guidance
    1. A stimulus is a change in the environment that can be detected.
    2. Example: light, sound, temperature change, touch, or a chemical.

  5. Question 5

    Paper 4 Both 3 marks Difficulty 3/5

    State the difference between a sensory neurone and a motor neurone in terms of structure and function.

    Show model answer and marking guidance
    1. Sensory neurone carries impulses from receptors to the CNS (brain or spinal cord).
    2. Motor neurone carries impulses from the CNS to effectors (muscles or glands).
    3. Sensory neurone has its cell body along the axon; motor neurone has its cell body at one end.

Mark the set consistently

Award a point only when the idea is clearly present in the written answer. Correct any missed point in a complete sentence, then test the same skill on a different question several days later.

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