AQA GCSE Biology Biology Paper 1 (Foundation), June 2025: Question 3

16 marks · Low Demand difficulty · Short Answer

Identify white blood cell functions, calculate real cell width using magnification, analyze blood vessel data, and describe causes and treatments for coronary heart disease.

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Question

Question text

03 Blood contains different types of cell.

03.1 Complete the sentences.

Choose answers from the box.

[2 marks]

antibiotics antitoxins painkillers pathogens

White blood cells defend the body against .

Some white blood cells release chemicals that neutralise toxins. These chemicals

are called .

03.2 Figure 3 shows a white blood cell.

Figure 3

The image of the white blood cell in Figure 3 is magnified 4000 times.

Calculate the real width of the white blood cell.

[4 marks]

Complete the following steps.

Measure width W in millimetres (mm).

*12* Width W = mm

Convert your measurement to micrometres (μm).

1 millimetre (mm) = 1000 micrometres (μm).

Width W in micrometres = μm

Calculate the real width of the white blood cell.

Use the equation:

width W (μm)

real width =

magnification

Real width = μm

Table 3 shows information about different types of blood vessel.

Table 3

Width of blood vessel in Pressure of blood travelling

Blood vessel

micrometres (μm) through the blood vessel

Artery 10 000 High

Capillary 10 Low

Vein 20 000 Very low

03.3 The width of a red blood cell is 8 μm.

Figure 4 shows red blood cells in one type of blood vessel.

Figure 4

Which type of blood vessel is shown in Figure 4?

Use Table 3.

[1 mark]

Tick ( ) one box.

Artery

Capillary

Vein 15

03.4 Explain why arteries need to have thick walls.

Use Table 3.

[2 marks]

Coronary arteries in the heart can become narrowed.

03.5 What happens inside coronary arteries to cause them to become narrowed?

[1 mark]

03.6 Explain why narrowed coronary arteries can be dangerous.

[2 marks]

03.7 Treatments are available for some cardiovascular diseases.

Draw one line from each cardiovascular disease to a treatment for the disease.

[3 marks]

03.8 Why is coronary heart disease described as a ‘non-communicable disease’?

[1 mark]

Mark scheme

Show the mark scheme

Question 3

AO /

Question Answers Extra information Mark

Spec Ref.

03.1 in this order only

pathogens 1 AO1

4.3.1.1

antitoxins 1 AO1

4.3.1.6

4.2.2.3

AO /

Spec Ref.

03.2 measurement AO2

60 (mm) allow measurement in the range 1 4.1.1.5

59 (mm) to 61 (mm)

conversion allow correct conversion from 1

60 000 (μm) incorrect measurement

substitution allow correct substitution using 1

60 000 incorrect conversion

4 000

real width allow correct calculation using 1

15 (μm) incorrectly converted value

AO /

Spec Ref.

03.3 capillary 1 AO3

4.2.2.2

4.2.2.3

AO /

Spec Ref.

03.4 (blood in arteries) has high 1 AO3

pressure 4.2.2.2

(so need thick walls) to ignore to increase the pressure 1

withstand / maintain the

pressure

(so need thick walls) to prevent

bursting

allow 2 marks for to withstand /

maintain high pressure

AO /

Spec Ref.

03.5 deposits / build-up / increase of allow deposits / build-up / 1 AO1 11

fat(ty material) increase of cholesterol 4.2.2.4

allow deposits / build-up /

increase of plaque

AO /

Spec Ref.

03.6 less / no blood flow 1 AO1

4.2.2.4

(so) less / no oxygen / glucose 1

transported (to heart / body)

allow 2 marks for less

oxygenated blood flows

if no other marks awarded allow

1 mark for idea that it will lead to

a heart attack

AO /

Question Answers Mark

Spec Ref.

03.7 AO1

4.2.2.4

do not accept more than one line from a box on the left

AO /

Spec Ref.

03.8 because it cannot be spread / allow not contagious / infectious 1 AO2

passed on (from one person to ignore because it is a lifestyle 4.2.2.4

another) disease

because it is not caused by a

pathogen / bacterium / virus /

fungus / protist / microorganism

/ microbe

Total Question 3 16

How to answer it

Blood Components, Circulation, and Cardiovascular Disease

What this question tests

This question covers fundamental concepts from AQA GCSE Biology Topic 2 (Organisation) and Topic 3 (Infection and Response):

White blood cell roles: defending against pathogens and producing antitoxins.
Microscopy skills: measuring in millimetres (mm), converting to micrometres (µm), and using the magnification formula: real size = image size ÷ magnification .
Structure and function of blood vessels (arteries vs. capillaries).
Causes, pathology, and medical treatments for Coronary Heart Disease (CHD).
Defining the term non-communicable disease accurately.

Question 03.1 • 2 Marks

White Blood Cell Functions

Sentence Completion from Given Options

✅ Correct Answers

1. White blood cells defend the body against pathogens. [1 mark]

2. These chemicals are called antitoxins. [1 mark]

💡 Key Knowledge

Pathogen: A microorganism that causes disease (bacteria, viruses, fungi, protists).
Antitoxins: Specific chemicals produced by white blood cells that bind to and neutralise harmful bacterial toxins.
Antibiotics: Medicines that kill bacteria (not produced naturally by our white blood cells!).

Examiner Insight: Answers must be in this exact order. A common slip-up is confusing antibodies (bind to antigens on pathogens) with antitoxins (neutralise toxins produced by bacteria).

Question 03.2 • 4 Marks

Magnification & Cell Size Calculation

Guided Step-by-Step Measurement and Conversion

📐 Step-by-Step Calculation

Measure width W: Use a ruler across the bracketed line.
60 mm (allow 59–61 mm) [1 mark]
Convert mm to µm: Multiply by 1000.
60 × 1000 = 60 000 µm [1 mark]
Substitute into formula:
real width = 60 000 ÷ 4000 [1 mark]
Calculate final answer:
15 µm [1 mark]

❌ Common Errors to Avoid

Unit conversion error: Dividing by 1000 instead of multiplying, giving 0.06 µm. Remember: 1 mm = 1000 µm , so the number in µm must always be much larger!
Skipping substitution: Even if your final mental math is wrong, writing the substitution 60 000 / 4000 secures the method mark.
Error Carried Forward (ECF): If you measured 58 mm incorrectly, but multiplied by 1000 (58 000) and divided by 4000 (14.5 µm), you still earn 3 out of 4 marks!

Questions 03.3 & 03.4 • 3 Marks Total

Blood Vessel Identification & Artery Adaptations

Linking Data to Structure and Function

✅ Correct Answers

03.3 (1 mark):
Tick: Capillary

03.4 (2 marks):
1. Blood in the arteries is under high pressure. [1 mark]
2. Thick walls are needed to withstand the high pressure / prevent bursting. [1 mark]

🧠 Exam Technique: Using Table 3

For 03.3: Red blood cells are 8 µm wide. Capillaries have a lumen diameter of ~10 µm. The diagram clearly shows red blood cells moving in single file through a very narrow vessel.
For 03.4: The question states: "Use Table 3." Look at the table: the blood pressure in an artery is explicitly stated as "High". You must state this fact to earn your first mark!

❌ Crucial Misconception in 03.4

Do NOT write that thick walls "increase the pressure" or "create high pressure". The mark scheme explicitly states "ignore to increase the pressure". Contraction of the ventricles in the heart creates the high pressure; artery walls merely withstand and maintain it.

Questions 03.5 & 03.6 • 3 Marks Total

Coronary Heart Disease (CHD)

Causes and Biological Consequences

03.5: Cause of Narrowing [1 mark]

Accepted answer:

Build-up / deposits / accumulation of fatty material (or cholesterol / plaque).

03.6: Why It Is Dangerous [2 marks]

Must give a 2-step explanation:

Reduces / restricts blood flow to heart muscle. [1 mark]
Leads to less oxygen (or glucose) reaching heart muscle cells, preventing respiration / leading to a heart attack. [1 mark]

Examiner Insight for 03.6: Writing "causes a heart attack" on its own only scores 1 compensatory mark if no other marks are achieved. Top responses explain the mechanism: narrowed lumen → reduced blood flow → lack of oxygen to heart muscle.

Questions 03.7 & 03.8 • 4 Marks Total

Treatments and Disease Classification

03.7: Matching Treatments [3 marks]

Cardiovascular Disease	Correct Treatment
A blocked coronary artery	Stent (wire mesh tube)
Heart failure	Heart transplant
High blood cholesterol	Statins (drugs)

Note: Antibiotics is an incorrect distractor (they treat bacterial infections).

03.8: Non-Communicable Definition [1 mark]

Correct Answer:

It cannot be transmitted / spread / passed from person to person.
OR It is not caused by a pathogen (microorganism / virus / bacteria).

Trap: Stating "because it is caused by bad lifestyle / diet" earns 0 marks. This describes a risk factor, not the definition of non-communicable!

Topics

Biology · B1: Cell Biology · B2: Organisation · B3: Infection and Response

Question and mark scheme from the AQA GCSE Biology examination, Biology Paper 1 (Foundation), June 2025. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.