IGCSE Biology Topic 14: Coordination and Response MCQs – 30 Practice Questions with Answers (Cambridge 0610)
Free practice for Cambridge IGCSE Biology 0610 on coordination and response, covering the nervous system, the eye, hormones, homeostasis and plant tropisms, with every question followed by a worked explanation.
The Nervous System, Reflexes and Synapses
Q1. Which organs make up the central nervous system in mammals?
- (A) The nerves in the arms and legs only
- (B) The sense organs and the effectors
- (C) The brain and the spinal cord
- (D) The glands and the blood vessels
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Answer: C – The central nervous system consists of the brain and the spinal cord, which process information and coordinate responses.
Q2. What is the peripheral nervous system?
- (A) The nerves outside the brain and spinal cord
- (B) The part of the brain that controls memory
- (C) The glands that release hormones into the blood
- (D) The receptors found only in the eye
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Answer: A – Nerves running outside the brain and spinal cord form the peripheral nervous system, linking the central system to the rest of the body.
Q3. What is the overall role of the nervous system?
- (A) To transport oxygen around the body in red blood cells from the lungs to the tissues
- (B) To digest food into soluble molecules
- (C) To produce hormones for growth
- (D) To coordinate and regulate body functions
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Answer: D – The nervous system coordinates and regulates body functions by carrying electrical impulses between receptors, the central nervous system and effectors.
Q4. In a reflex arc, which neurone carries an impulse from a receptor towards the central nervous system?
- (A) The motor neurone
- (B) The sensory neurone
- (C) The effector neurone
- (D) The gland neurone
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Answer: B – Sensory neurones carry impulses from receptors into the central nervous system.
Q5. Where is the relay neurone found in a simple reflex arc?
- (A) In the central nervous system, linking the sensory and motor neurones
- (B) In the receptor, detecting the stimulus and starting the impulse that travels to the brain
- (C) In the muscle, causing it to contract
- (D) In the blood, carrying the impulse to the brain
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Answer: A – The relay neurone sits within the central nervous system and passes the impulse from the sensory neurone to the motor neurone.
Q6. Which neurone carries an impulse from the central nervous system to an effector?
- (A) The sensory neurone
- (B) The relay neurone
- (C) The motor neurone
- (D) The receptor neurone
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Answer: C – Motor neurones carry impulses out of the central nervous system to muscles or glands that produce the response.
Q7. Which sequence correctly describes a simple reflex arc?
- (A) Effector, motor neurone, relay neurone, sensory neurone, receptor
- (B) Receptor, sensory neurone, relay neurone, motor neurone, effector
- (C) Receptor, motor neurone, relay neurone, sensory neurone, effector
- (D) Sensory neurone, receptor, motor neurone, relay neurone, effector
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Answer: B – A stimulus is detected by a receptor, then the impulse travels through sensory, relay and motor neurones to the effector.
Q8. Why is a reflex action useful when a hand touches a hot surface?
- (A) It allows the person to think carefully before reacting and to choose the best response deliberately
- (B) It sends the impulse to the stomach first
- (C) It stops all other nerve impulses in the body
- (D) It produces an automatic, rapid response that protects the body from harm
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Answer: D – A reflex action integrates a stimulus with an effector response automatically and rapidly, without waiting for conscious thought.
Q9. Which structures act as effectors in a reflex action?
- (A) Muscles and glands
- (B) Receptors and sense organs only
- (C) The brain and spinal cord only
- (D) Blood vessels and bones only
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Answer: A – Muscles contract and glands secrete in response to impulses, so both are effectors.
Q10. What is a synapse?
- (A) A type of sensory receptor in the skin
- (B) A long fibre that carries impulses inside a single neurone
- (C) A junction between two neurones
- (D) A gland that releases adrenaline
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Answer: C – A synapse is the junction where an impulse passes from one neurone to the next.
Q11. What is stored in the vesicles at a synapse?
- (A) Glucose molecules for energy
- (B) Neurotransmitter molecules
- (C) Hormones for the whole body
- (D) Oxygen for the next neurone
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Answer: B – Vesicles in the end of a neurone contain neurotransmitter molecules that are released when an impulse arrives.
Q12. What happens after neurotransmitter molecules are released into the synaptic gap?
- (A) They are carried away in the blood to distant target organs around the body for a general hormonal response throughout the body
- (B) They convert the next neurone into a muscle cell
- (C) They dissolve the receptor proteins on the next neurone
- (D) They diffuse across the gap and bind with receptor proteins on the next neurone, stimulating an impulse there
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Answer: D – The molecules diffuse across the synaptic gap, bind to receptors, and trigger a new impulse in the following neurone.
Q13. Why can an impulse at a synapse travel in only one direction?
- (A) Neurotransmitter molecules are released on one side only and receptors are on the other side
- (B) The synaptic gap is too wide for impulses to cross backwards from the second neurone to the first
- (C) Motor neurones cannot receive impulses at all
- (D) The brain blocks any impulse that tries to reverse
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Answer: A – Because vesicles release transmitter on one side and receptors sit on the next neurone, the signal can only move forward.
The Eye and Sense Organs
Q14. Sense organs are groups of receptor cells responding to specific stimuli. Which stimulus does a receptor in the retina respond to?
- (A) Sound waves
- (B) Chemicals in food
- (C) Light
- (D) Changes in blood glucose
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Answer: C – The retina contains light receptors, so its receptor cells respond to light.
Q15. What is the function of the iris in the eye?
- (A) It focuses light onto the retina
- (B) It controls how much light enters the pupil
- (C) It carries impulses to the brain
- (D) It contains the receptors for colour vision
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Answer: B – The iris adjusts the size of the pupil, and so controls the amount of light entering the eye.
Q16. What is the function of the lens in the eye?
- (A) It controls the diameter of the pupil
- (B) It produces tears to keep the eye moist
- (C) It detects different colours of light
- (D) It focuses light onto the retina
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Answer: D – The lens refracts light so that a focused image falls on the retina.
Q17. Which part of the eye contains light receptors, some sensitive to light of different colours?
- (A) The retina
- (B) The cornea
- (C) The optic nerve
- (D) The blind spot
Show Answer
Answer: A – The retina is the layer at the back of the eye that contains the light-detecting receptor cells.
Q18. What is the function of the optic nerve?
- (A) It refracts light as it enters the eye through the cornea and focuses it onto the retina
- (B) It carries impulses from the eye to the brain
- (C) It changes the shape of the lens
- (D) It controls the size of the pupil
Show Answer
Answer: B – Impulses generated in the retina travel along the optic nerve to the brain for interpretation.
Q19. In bright light, what happens to the pupil, and why is this helpful?
- (A) The pupil widens to let in as much light as possible so that vision stays clear in dim conditions
- (B) The pupil stays the same size in all light levels
- (C) The pupil closes completely so no light enters
- (D) The pupil becomes smaller, reducing the light entering the eye and protecting the retina
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Answer: D – In the pupil reflex, bright light causes the pupil diameter to decrease, limiting the light that reaches the retina.
Hormones and Homeostasis
Q20. Which definition best describes a hormone?
- (A) An electrical impulse travelling rapidly along a neurone from a receptor towards the central nervous system and then on to an effector
- (B) A chemical released at a synapse between two neurones
- (C) A chemical substance produced by a gland, carried by the blood, which alters the activity of specific target organs
- (D) A receptor cell that detects a change in the environment
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Answer: C – Hormones are made by glands, travel in the blood, and act only on their target organs.
Q21. Which gland secretes insulin, and what does insulin do to blood glucose concentration?
- (A) The adrenal gland, which raises blood glucose during fight or flight situations in the body
- (B) The pancreas, which decreases blood glucose concentration
- (C) The ovary, which keeps blood glucose unchanged
- (D) The testis, which converts glucose to urea
Show Answer
Answer: B – The pancreas secretes insulin, and insulin decreases blood glucose concentration.
Q22. How does glucagon help when blood glucose concentration falls too low?
- (A) It raises blood glucose concentration, with the liver releasing glucose into the blood
- (B) It blocks the release of insulin permanently so that blood glucose can never fall too low again
- (C) It converts blood glucose into urea
- (D) It stops the kidneys from filtering the blood
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Answer: A – Glucagon is secreted by the pancreas and acts with the liver to raise blood glucose concentration back towards normal.
Q23. Which gland secretes adrenaline, and in which situation is it released?
- (A) The pancreas, during sleep
- (B) The ovaries, during digestion
- (C) The testes, during growth
- (D) The adrenal glands, in fight or flight situations
Show Answer
Answer: D – Adrenaline is secreted by the adrenal glands when the body faces a stressful fight or flight situation.
Q24. Which comparison of nervous and hormonal control is correct?
- (A) Nervous control is slow and long-lasting, while hormonal control is fast and short-lived
- (B) Both types of control act at exactly the same speed
- (C) Nervous control is fast and short-lived, while hormonal control is slower and longer-lasting
- (D) Hormonal control uses electrical impulses, while nervous control uses the blood
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Answer: C – Nervous responses act quickly and fade quickly, whereas hormones travel in the blood and their effects last longer.
Q25. What is homeostasis?
- (A) The rapid withdrawal of a hand from danger
- (B) The maintenance of a constant internal environment
- (C) The growth of a plant shoot towards light
- (D) The production of hormones by the adrenal glands
Show Answer
Answer: B – Homeostasis keeps conditions inside the body, such as blood glucose and temperature, steady despite outside changes.
Q26. On a hot day, which two responses help a mammal lose heat from the skin?
- (A) Sweating and vasodilation of arterioles supplying skin capillaries
- (B) Shivering and vasoconstriction of skin arterioles
- (C) Sweating and contraction of hair erector muscles
- (D) Vasoconstriction and a thickening layer of fatty tissue
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Answer: A – Sweating cools the skin by evaporation, while vasodilation brings more warm blood to skin capillaries so heat can be lost.
Q27. In cold conditions, which responses help a mammal conserve and generate heat?
- (A) Sweating and vasodilation of skin arterioles
- (B) Increased breathing rate and pupil widening
- (C) Relaxation of hair erector muscles and increased sweating
- (D) Shivering and vasoconstriction of arterioles supplying skin surface capillaries
Show Answer
Answer: D – Shivering generates heat in muscles, while vasoconstriction reduces blood flow near the skin surface and so reduces heat loss.
Tropic Responses in Plants
Q28. What is phototropism?
- (A) Growth towards or away from water
- (B) Growth towards or away from a chemical
- (C) Growth towards or away from the direction of the light source
- (D) Growth towards or away from touch
Show Answer
Answer: C – In phototropism, parts of a plant grow towards or away from light, with shoots typically growing towards it.
Q29. Which statement correctly describes gravitropism in a seedling?
- (A) Roots grow towards gravity and shoots grow away from gravity
- (B) Roots and shoots both grow towards gravity
- (C) Roots and shoots both grow away from gravity
- (D) Roots grow away from gravity and shoots grow towards gravity
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Answer: A – Gravitropism is growth in response to gravity: roots show positive gravitropism and shoots show negative gravitropism.
Q30. How does auxin control the bending of a shoot towards light?
- (A) Auxin is made in the roots and stops all shoot growth
- (B) Auxin made in the shoot tip becomes unequally distributed, and the shaded side elongates more, bending the shoot towards light
- (C) Auxin destroys cells on the shaded side of the shoot
- (D) Auxin travels in the blood to the leaves and closes the stomata
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Answer: B – Auxin diffuses from the shoot tip, accumulates more on the shaded side, stimulates greater cell elongation there, and the shoot bends towards the light.
Revisit any questions you missed, especially the reflex arc order, the parts of the eye, and the contrast between nervous and hormonal control.