AQA AS Level Biology Paper 1, June 2025: Question 6
9 marks · Medium difficulty · Practical Techniques & Data Analysis
Analyze data on lung function in emphysema, calculate rate of exhalation, and evaluate epidemiological data linking smoking to COPD.
Practise this questionQuestion
Question text
06 A scientist investigated the effect of the lung disease emphysema on lung function.
They investigated lung function in:
• a person with emphysema
• a person with healthy lungs.
The scientist told each person:
• to breathe in fully
• then breathe out fully and as quickly as possible.
The scientist measured the volume of air exhaled in one breath.
Figure 7 shows the scientist’s results.
Figure 7
Figure 7 not reproduced here due to third-party copyright restrictions.
The figure is adapted from
https://www.thelancet.com/journals/lancet/article/PIIS0140673604168554/fulltext
06.1 Forced expiratory volume (FEV1) is the maximum volume of air that is breathed out in
one second. FEV1 is used to measure lung health.
What is the percentage decrease in FEV1 for the person with emphysema compared
with the healthy person?
Tick ( ) one box.
[1 mark]
23.1%
30.0%
42.5%
73.9% 15
06.2 Use Figure 7 to determine the speed of exhalation, in dm3 s–1, for the person with
healthy lungs at time = 2 s
Show your working.
[2 marks]
*14* Speed of exhalation dm3 s–1
06.3 The main effects of emphysema on the lungs are the breakdown of:
• the walls of the alveoli
• the elastic tissue in the lungs.
Use this information and the data in Figure 7 to suggest why gas exchange is
reduced in a person with emphysema.
[3 marks]
06.4 Chronic obstructive pulmonary disease (COPD) is the name for a group of lung
diseases that cause breathing difficulties. This includes emphysema.
Figure 8 shows the number of deaths caused by COPD from 1980–2016. It also
shows the percentage of the population who smoked, for the same time period.
Figure 8
A journalist looked at the data in Figure 8 and concluded that smoking is a cause of
COPD.
Evaluate this conclusion.
[3 marks]
Mark scheme
Show the mark scheme
Question Marking Guidance Mark Comments
42.5 % 1
06.1 (1 x
AO2)
Correct answer within range of 0.3 to 0.5 (dm3 s-1)
= 2 marks;;
Incorrect answer but shows correct tangent (at 2 Ignore tangent on
seconds) = 1 mark 2 emphysema line
(1 x
06.2
OR AO1, 1
x AO2)
2.5 (for incorrect method with correct reading at 2
seconds (5) and division by correct time (2))
= 1 mark;
1. Low FEV1/Figure 7 shows less air exhaled;
2. (Destruction of alveoli walls means) decrease in
surface area (for gas exchange);
OR
(Destruction of alveoli walls may) increase
diffusion distance (due to scar tissue); 3
(1 x
06.3
3. Lack of (elastic) recoil/tissue makes exhalation AO1, 2
more difficult x AO2)
OR
Lack of (elastic) recoil/tissue reduces
concentration gradient (between alveoli and
blood);
1. Positive correlation between smoking and 1 and 2. Accept
COPD deaths in men; description of
correlation
2. No correlation shown between smoking and
2. Accept ‘(slight)
COPD deaths in women; 3
negative correlation’
06.4 (3 x for ‘no correlation’
3. Named/other factors not taken into AO3)
10 consideration; 3. Other factors
include e.g. passive
smoking, occupational
exposure, medical
improvements
How to answer it
Emphysema, Lung Function & Evaluating Risk Factors
This question assesses your understanding of human gas exchange, the pathological impacts of lung disease (specifically emphysema and COPD), graphical mathematical skills (calculating rates of change via tangents), and critical evaluation of epidemiological data (distinguishing between correlation and causation).
Percentage Decrease in Forced Expiratory Volume (FEV₁)
Calculation / Graph Reading
✅ Correct Answer
42.5% (third checkbox ticked)
📐 Calculation Breakdown
- Identify baseline (Healthy): Read volume at 1.0 s for healthy lung (4.0 dm³).
- Identify emphysema volume: Read volume at 1.0 s for emphysema patient (2.3 dm³).
- Calculate absolute decrease: 4.0 - 2.3 = 1.7 dm³.
- Calculate percentage decrease: (1.7 ÷ 4.0) × 100 = 42.5%.
❌ Common Error
Dividing by the new value (2.3 dm³) instead of the original healthy value (4.0 dm³), which incorrectly gives 73.9%. Always divide by the baseline/healthy reference value.
Rate of Exhalation at a Specific Time (t = 2 s)
Determining Rate from a Curve Using a Tangent
✅ Correct Answer Range
Any value within the range 0.3 to 0.5 dm³ s⁻¹ (with appropriate tangent shown on Figure 7).
• 2 marks: Correct answer between 0.3 and 0.5 dm³ s⁻¹.
• 1 mark: Tangent drawn correctly at t = 2 s on the healthy curve, but miscalculated.
• Compensatory 1 mark: Value of 2.5 obtained by dividing volume at 2 s (5.0 dm³) by time (2 s) without drawing a tangent.
🧠 Exam Technique: Drawing Tangents
- Place a clear plastic ruler so it touches the curve only at t = 2.0 s for the healthy person.
- Ensure the angle between ruler and curve is symmetric on both sides of the point.
- Draw a long straight line extending well beyond the point of contact.
- Form a large right-angled triangle: gradient = Δy ÷ Δx = change in volume ÷ change in time .
❌ Common Traps
- Dividing y by x directly: Simply doing 5.0 dm³ ÷ 2 s = 2.5 dm³ s⁻¹. Curves have changing rates; you must use a tangent!
- Drawing the tangent on the emphysema curve instead of the healthy curve (explicitly ignored by examiners).
Mechanism of Reduced Gas Exchange in Emphysema
Applying Fick's Law and Lung Anatomy
✅ Marking Points (Award any 3)
- Low FEV₁ / Less air exhaled: Data from Figure 7 shows less air can be forced out quickly.
- Surface Area / Diffusion Distance: Destruction of alveolar walls reduces the total surface area available for gas exchange OR increases diffusion distance (e.g. scar tissue/fibrosis).
- Loss of Elastic Recoil: Loss of elastin reduces elastic recoil, making ventilation/exhalation less efficient OR reduces the oxygen concentration gradient between alveoli and blood capillaries.
💡 Key Knowledge: Fick's Law of Diffusion
Rate of Diffusion ∝ (Surface Area × Concentration Difference) ÷ Diffusion Pathway
- Alveolar breakdown: Fewer, larger air spaces = dramatically decreased surface area-to-volume ratio.
- Elastic recoil: Normal passive recoil pushes stale, CO₂-rich air out. Without it, stale air remains trapped, preventing a steep concentration gradient for O₂ from being maintained.
🧠 Examiner Insight
Notice the command words: "Use this information and the data in Figure 7". Many candidates fail to mention the graphical data (e.g. low FEV₁ / lower exhaled volume) and lose Mark Point 1 entirely.
Evaluating a Conclusion: Smoking as a Cause of COPD
Data Evaluation: Correlation vs. Causation
✅ Marking Points (3 Marks Available)
- Supports conclusion (in men): Positive correlation between smoking rates and COPD deaths in men (as smoking decreased, deaths decreased).
- Does NOT support conclusion (in women): No correlation (or slight negative correlation) between smoking rates and COPD deaths in women (smoking rates fell, but deaths remained constant or slightly rose).
- Confounding factors: Other variables were not controlled/considered (e.g. air pollution, occupational exposure, passive smoking, improved medical care, or a time lag in disease development).
🧠 Top-Level "Evaluate" Technique
- Look for both sides: Always provide points that support the claim AND points that challenge it.
- Compare groups: Look separately at men and women—trends often differ between demographic groups.
- State the golden rule: Correlation does not prove causation; mention uncontrolled confounding variables.
❌ Common Errors
- Making a sweeping claim that the graph "proves" smoking causes COPD.
- Ignoring the trend for women entirely and only looking at men.
- Vaguely stating "other factors" without naming a plausible biological/environmental factor (e.g., passive smoking, industrial dust, genetics).
Topics
Biology · Practical skills · 3.3 Organisms exchange substances with their environment · Data analysis
Question and mark scheme from the AQA AS Level Biology examination, Paper 1, June 2025. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.