Biology 0610 · syllabus 14

Cambridge IGCSE Biology 0610 — Coordination and response topical past papers

Neurones, reflex arcs and synapses, the eye, hormones and adrenaline, homeostasis of blood glucose and temperature, and plant growth responses controlled by auxin.

Questions: 616
Years: 2009–2026
With mark scheme: 100%
Questions 2022–2026: 242

Practise this topic Build a mock from this chapter

Anyone can browse these pages. Opening the questions and their mark schemes takes a free Momentum account.

What Coordination and response covers

The nervous system — the brain and spinal cord, which form the central nervous system, and the nerves outside them — coordinates and regulates the body by sending electrical impulses along neurones. In a reflex arc, a receptor detects a stimulus, a sensory neurone carries the impulse to a relay neurone in the central nervous system, and a motor neurone carries it on to an effector, a muscle or a gland, so the response is fast and automatic, like pulling your hand away from something hot. Neurones meet at synapses. Extended candidates describe what happens there: an impulse releases neurotransmitter from vesicles, the neurotransmitter diffuses across the gap and binds to receptor proteins on the next neurone, starting a new impulse; because only one side releases neurotransmitter, impulses cross in one direction only.

Each sense organ is a group of receptor cells sensitive to one kind of stimulus — light, sound, touch, temperature or chemicals. In the eye, the cornea bends (refracts) light as it enters, the lens brings it to a focus on the retina, the iris adjusts the size of the pupil and so the amount of light let in, and the optic nerve takes impulses to the brain; in bright light the pupil reflex narrows the pupil. Extended candidates explain the reflex with the circular and radial muscles of the iris, explain accommodation for near and distant objects, and describe the rods and cones of the retina. Hormones are the second control system: chemicals made by glands and carried in the blood to target organs. Adrenaline from the adrenal glands prepares the body for 'fight or flight', raising the breathing rate, the heart rate and the diameter of the pupils; hormonal responses are slower than nervous ones but last longer.

Homeostasis is keeping the internal environment constant. All candidates need to know that insulin lowers the blood glucose concentration; Extended candidates explain control by negative feedback about a set point, the roles of insulin, glucagon and the liver in keeping blood glucose steady, the treatment of Type 1 diabetes, and the control of body temperature by sweating, shivering, insulation and the widening and narrowing of the arterioles that supply the skin. Plants respond too: shoots grow towards light and away from gravity, and roots grow towards gravity. Extended candidates explain the shoot responses with auxin, which is made in the shoot tip, collects on one side and makes the cells there elongate more.

In the syllabus

The headings this topic has in the Cambridge International 2026–2028 syllabus, as the board prints them.

14 Coordination and response
14.1 Coordination and response
14.2 Sense organs
14.3 Hormones
14.4 Homeostasis
14.5 Tropic responses

Read the syllabus on the board’s website

What you should be able to do

Describe a reflex arc from receptor to effector, and explain why reflex actions are fast and automatic
Identify the parts of the eye, state the function of each and explain the pupil reflex
Name the glands that make adrenaline, insulin, testosterone and oestrogen, describe the effects of adrenaline, and compare nervous with hormonal control
Set up experiments showing how shoots and roots respond to light and to gravity
Explain events at a synapse, accommodation, and the roles of rods and cones (Extended)
Explain the control of blood glucose and body temperature by negative feedback, and the role of auxin in shoots (Extended)

Key ideas

Reflex arc: receptor → sensory neurone → relay neurone → motor neurone → effector
Nervous control is fast and short-lived; hormonal control is slower and longer-lasting
In bright light the circular muscles of the iris contract and the radial muscles relax, narrowing the pupil (Extended)
For a near object the ciliary muscles contract, the suspensory ligaments slacken and the lens becomes fatter, refracting light more (Extended)
Insulin lowers blood glucose by making the liver store glucose as glycogen; glucagon raises it by making the liver turn glycogen back into glucose (Extended)

How Coordination and response has been examined

From 2022 to 2026, Coordination and response was on Paper 4 · Theory (Extended) in 13 of 14 exam series, worth about 12% of that paper’s marks.

How Coordination and response has been examined, by paper
Paper	Questions	Share of marks	Series
Paper 1 · Multiple Choice (Core)	92	7%	14 of 14
Paper 2 · Multiple Choice (Extended)	95	7%	14 of 14
Paper 3 · Theory (Core)	27	10%	11 of 14
Paper 4 · Theory (Extended)	24	12%	13 of 14
Paper 6 · Alternative to Practical	4	5%	4 of 14

Momentum’s own count, over the questions in its bank for these years: a series is one exam session, every zone included, and a question filed under two chapters counts in both. Median marks per question: 1.

Filed in Momentum under: Co-ordination and Response.

Mistakes that cost marks

Writing 'the nerves send a message' in a reflex answer — name the impulse and each neurone in order, from receptor to effector
Saying the pupil widens in bright light — it narrows, letting less light in to protect the retina; it widens in dim light
Saying blood vessels move closer to the skin when you are hot — no vessel moves; the arterioles supplying the skin capillaries widen, so more blood flows near the surface (Extended)
Saying the capillaries dilate or constrict — it is the arterioles that widen and narrow; capillary walls have no muscle (Extended)
Writing that insulin turns glucose into glucagon — insulin causes glucose to be stored as glycogen; glucagon is a separate hormone (Extended)
Saying the lit side of a shoot grows faster — auxin collects on the shaded side, where cells elongate more, so the shoot bends towards the light (Extended)

Exam technique

When comparing nervous and hormonal control, write matched pairs: impulses along neurones against hormones in the blood, fast against slow, brief against long-lasting
In tropism experiments, change only the direction of light or of gravity, include a control, and use a clinostat, which turns seedlings slowly, to cancel out one-sided gravity or light
In homeostasis answers, follow the loop: the change detected, the response that opposes it, and the return to the set point (Extended)
For accommodation, state the ciliary muscles, the suspensory ligaments, the lens shape and the refraction, in that order, for the distance in the question (Extended)

Practising in Momentum

Every question in a chapter as one list, from every paper and year in the bank, newest first or shuffled.
Each question turns over to its own part of the mark scheme, where the board published one.
Narrow by paper, year, session, zone and marks, and star the questions worth keeping.
Pick chapters, a number of questions and a time, and the exam builder draws a mock to sit and mark.