Edexcel International GCSE Biology 4BI1: Co-ordination and response – Practice Questions

These are original questions written for Marlbridge, for revision and practice on this content. They are not reproduced past-paper questions, and they do not replicate the exam’s exact structure, question count or mark tariffs – examination boards hold copyright in their own papers. Use these alongside the official past papers from your board or school.

These questions cover sub-topic 2(j), Co-ordination and response (points 2.80–2.95B), of the Pearson Edexcel International GCSE Biology (4BI1) specification, Issue 3, for the June and November series examined under Issue 3. The course is untiered and a calculator may be used on both papers. Question 12 tests the bold B statement 2.95B and is labelled “Paper 2 only”.

Learn the content first in the study guide and the revision notes. The course hub is Edexcel IGCSE Biology and the printable checklist lists every point. For other parts of Topic 2, try the cell structure practice questions.

Questions

1. State what is meant by homeostasis and give two examples of it in the human body. [3]

2. A cat hears a dog bark and runs up a tree. Identify:

(a) the stimulus [1] (b) the receptor [1] (c) an effector [1]

3. A bean seedling is laid on its side in a dark cupboard for two days.

(a) Describe the direction of growth of the root and of the shoot. [2] (b) Name the stimulus and the type of response shown by the root. [2]

4. A student removes the tips from oat shoots that had been lit from one side. She places each tip on two agar blocks separated by a thin barrier, so that auxin from the lit side and the shaded side collects in different blocks. She measures the auxin in each block in arbitrary units.

Block	Auxin (arbitrary units)
Lit side	27
Shaded side	48

(a) Calculate the percentage of the total auxin that collected on the shaded side. [2] (b) Use the results to explain why an intact shoot bends towards the light. [4]

5. Give four differences between nervous and hormonal communication in humans. [4]

6. Describe how an impulse passes from one neurone to the next across a synapse. [4]

7. A person steps barefoot on a sharp stone and lifts the foot before feeling any pain.

(a) Describe the pathway of this reflex, from receptor to effector. [4] (b) Explain why this response is an advantage. [2]

8. A student reading a phone looks up at a bus approaching in the distance.

(a) Name the part of the eye that contains the light receptors and the part that carries impulses to the brain. [2] (b) Describe how the eye adjusts so that the distant bus is focused on the retina. [4]

9. Explain how the eye responds when a person walks from a dark room into bright sunlight. [3]

10. A scientist measures blood flow through the skin of a volunteer’s hand at two air temperatures.

Air temperature	Skin blood flow (arbitrary units)
30 °C	18.0
10 °C	4.5

(a) Calculate the percentage change in skin blood flow from 30 °C to 10 °C. [2] (b) Explain how the change in blood flow helps keep body temperature constant at 10 °C. [3] (c) Explain how sweating cools the body at 30 °C. [2]

11. A volunteer drinks a glucose solution. Her blood glucose concentration peaks at 8.4 mmol/dm³ at 40 minutes and falls to 5.4 mmol/dm³ at 100 minutes.

(a) Calculate the mean rate of fall in blood glucose between 40 and 100 minutes. Give the unit. [2] (b) Name the hormone responsible for the fall, state where it is made, and explain how it lowers blood glucose. [3] (c) Later she is startled by a loud noise. Name the hormone released and give two of its effects. [3]

12. (Paper 2 only)

(a) A man’s urine production falls from 150 cm³ per hour to 60 cm³ per hour after a long walk on a hot day. Calculate the percentage change. [2] (b) Explain the role of ADH in causing this change. [4] (c) Name the gland that secretes FSH and LH, and state one role of each in the menstrual cycle. [3]

Answers

1. Maintenance of a constant internal environment [1]; body water content [1]; body temperature [1] [3] Examiner insight: “Keeping the body the same” is too vague for the definition mark; the word “internal” (or “inside the body”) is expected.

2. (a) The sound of the bark [1] (b) Sound receptors in the ear [1] (c) Leg muscles [1] Examiner insight: “The ear” alone may lose the receptor mark if the scheme asks for receptors; and “the legs” is weaker than “leg muscles”, because an effector is a muscle or gland.

3. (a) Root grows (curves) downwards [1]; shoot grows (curves) upwards [1] (b) Gravity [1]; positive geotropism [1] Examiner insight: The cupboard is dark so that light cannot cause the response; naming light as the stimulus scores nothing, and “geotropism” without “positive” loses the second mark.

4. (a) 48 ÷ (48 + 27) × 100 [1] = 64% [1] (b) More auxin is on the shaded side (48 compared with 27 units) [1]; auxin causes cell elongation [1]; cells on the shaded side elongate more, so that side grows faster [1]; the shoot curves towards the light [1] Examiner insight: “Use the results” means a mark is reserved for quoting the data; an answer with no numbers from the table usually cannot reach full marks.

5. Nervous uses electrical impulses, hormonal uses chemicals [1]; nervous travels along neurones, hormones travel in the blood [1]; nervous is faster [1]; nervous effects are short-lived, hormonal effects last longer [1]. Also creditworthy in place of any one of these: nervous acts on a precise area, hormones can affect several organs. [4] Examiner insight: Each difference needs both sides stated or clearly implied; “hormones are slow” on its own is often accepted, but listing only features of one system rarely scores four.

6. Impulse arrives at the end of the first neurone [1]; neurotransmitter is released into the gap [1]; it diffuses across the gap [1]; it binds to receptors on the next neurone, starting a new impulse [1] [4] Examiner insight: “The impulse jumps across the gap” scores nothing; the marks are for the chemical neurotransmitter and the process of diffusion.

7. (a) Pain (pressure) receptors in the skin of the foot [1]; sensory neurone carries impulses to the spinal cord [1]; relay neurone in the spinal cord [1]; motor neurone to the leg muscle, which contracts [1] (b) The response is fast and automatic [1]; so damage to the foot is reduced [1] Examiner insight: This tests the reflex arc in a new context; keep the same three-neurone sequence and name the spinal cord, because “the brain” as the co-ordinator loses a mark.

8. (a) Retina [1]; optic nerve [1] (b) Ciliary muscle relaxes [1]; suspensory ligaments become tight [1]; lens is pulled thinner [1]; light is refracted less, so it focuses on the retina [1] Examiner insight: Accommodation is marked as a sequence; reversing one step (for example “ciliary muscle contracts”) usually costs that mark and makes the lens-shape mark inconsistent.

9. Circular muscles of the iris contract [1]; radial muscles relax [1]; pupil becomes smaller, so less light enters and the retina is protected [1] [3] Examiner insight: Naming “the iris muscles” without saying which set contracts gains little; the mark scheme rewards circular versus radial correctly matched.

10. (a) (4.5 − 18.0) ÷ 18.0 × 100 [1] = −75% (a 75% decrease) [1] (b) Vasoconstriction: arterioles supplying the skin capillaries narrow [1]; less blood flows near the skin surface [1]; so less heat is lost by radiation [1] (c) Water in sweat evaporates from the skin [1]; evaporation uses heat energy from the body [1] Examiner insight: In (b) “capillaries move away from the surface” is a common wrong idea and scores nothing; in (a) dividing by 4.5 instead of 18.0 loses both marks.

11. (a) (8.4 − 5.4) ÷ (100 − 40) = 3.0 ÷ 60 [1] = 0.05 mmol/dm³ per minute [1] (b) Insulin [1]; made in the pancreas [1]; causes the liver and muscles to convert glucose to glycogen (and cells to take up glucose) [1] (c) Adrenaline [1]; increases heart rate [1]; raises blood glucose by causing glycogen breakdown in the liver [1]. Also accept: increases breathing rate, or widens the pupils (any two effects). Examiner insight: In (a) the unit is part of the answer mark; in (b) “glucagon” for glycogen loses the mark even if the rest is right.

12. (a) (60 − 150) ÷ 150 × 100 [1] = −60% (a 60% decrease) [1] (b) Water lost in sweat makes the blood more concentrated [1]; the pituitary gland releases more ADH [1]; ADH makes the collecting ducts more permeable to water [1]; more water is reabsorbed into the blood, so less, more concentrated urine is made [1] (c) Pituitary gland [1]; FSH causes an egg to mature (and stimulates oestrogen production) [1]; LH triggers ovulation [1] Examiner insight: For (b), “ADH reabsorbs water” is wrong: the kidney reabsorbs water and ADH only changes the permeability of the collecting duct, so name the collecting duct to score.

Where marks are usually lost

• Leaving out “internal” from the homeostasis definition.
• Naming an organ (“the ear”, “the legs”) when the question asks for the receptor or effector.
• Not quoting numbers when a question says “use the results”.
• Saying auxin causes cell division instead of cell elongation.
• Describing the impulse “jumping” across a synapse.
• Putting the reflex through the brain instead of the spinal cord.
• Reversing the ciliary muscle action for near and distant objects.
• Dividing by the final value in a percentage change.
• Writing “glucagon” instead of glycogen.
• Saying ADH itself reabsorbs water.

Next steps

• Recap with the revision notes.
• Reread any weak section in the study guide.
• Browse other topics on the Edexcel IGCSE Biology hub.
• Track coverage with the printable checklist.
• Try all free 10-minute diagnostics.
• Book a free trial class.

Official syllabus

Pearson Edexcel International GCSE in Biology (4BI1) specification, Issue 3, first examination June 2019, Pearson Education Limited – Topic 2, Structures and functions in living organisms, sub-topic (j) Co-ordination and response.