AQA GCSE Biology Biology Paper 1 (Higher), November 2021: Question 7
19 marks · High Demand difficulty · Extended Answer
Explain cancer development, the effects of low blood cell counts, the mechanics of blood transfusion compatibility, risk probabilities, and the impact of a gall bladder blockage on fat digestion.
Practise this questionQuestion
Question text
07 Figure 11 shows where three of the same type of tumour were found in a patient.
Figure 11
Malignant tumours are cancers.
07.1 Describe what happens to cells when a tumour forms.
[1 mark]
07.2 What evidence is there in Figure 11 to suggest that the tumour in the lung
is malignant?
[1 mark]
07.3 Some types of cancer can cause the numbers of blood components in a person’s
body to fall to a dangerously low level.
A person with one of these types of cancer may experience symptoms such as:
• tiredness
*28* • frequent infections
• bleeding that will not stop after the skin is cut.
Explain how a very low number of blood components in the body can cause
these symptoms.
[6 marks]
Some patients with a very low number of blood cells may be given a blood
transfusion.
A blood transfusion is where a patient receives blood from a donor.
Different people have different blood groups.
Figure 12 shows:
• the red blood cells found in people with different blood groups
• the antibodies that can be made by people with different blood groups.
Figure 12
Antibodies can bind to antigens that have complementary shapes.
When antibodies bind to the antigens on red blood cells, many red blood cells begin to
clump together.
Each red blood cell is about 8 μm in diameter.
Many capillaries have an internal diameter of about 10 μm.
In one type of blood transfusion, only red blood cells from a donor are transferred to
the patient.
07.4 It is dangerous for a patient with blood group A to receive red blood cells from a donor
with blood group B.
Explain why.
[3 marks]
07.5 Explain why blood group O red blood cells can be given to patients with any
blood group.
[2 marks]
07.6 Table 4 shows some of the risks associated with blood transfusions.
Table 4
Risk Probability of risk occurring
Allergic reaction 0.9%
Hepatitis B infection 1 in (3 × 105)
Hepatitis C infection 6.7 × 10–7
*31* Kidney damage 1 in 70 000
Which risk has the lowest probability of occurring?
[1 mark]
Tick ( ) one box.
Allergic reaction
Hepatitis B infection
Hepatitis C infection
Kidney damage 33
07.7 A person has a tumour blocking the tube leading from the gall bladder to the
small intestine.
Explain why this person would have difficulty digesting fat.
[5 marks]
Mark scheme
Show the mark scheme
AO /
Question Answers Extra information Mark
Spec. Ref.
07.1 cells grow / divide abnormally / ignore mutation 1 AO1
uncontrollably 4.2.2.7
07.2 has spread to other parts / allow tumour has metastasised 1 AO2
organs of the body 4.2.2.7
or
has spread to the liver / lung
or
has formed a secondary tumour
07.3 Level 3: Relevant points (reasons/causes) are identified, given in 5‒6 AO2
detail and logically linked to form a clear account. 4.2.2.3
4.3.1.6
Level 2: Relevant points (reasons/causes) are identified, and there 3‒4 4.4.2.1
are attempts at logical linking. The resulting account is not fully 4.4.2.2
clear.
Level 1: Points are identified and stated simply, but their relevance 1‒2
is not clear and there is no attempt at logical linking.
No relevant content. 0
Indicative content:
Tiredness
• fewer red blood cells
• so less haemoglobin
• so less oxygen transported around the body
• so less (aerobic) respiration can take place
• so more anaerobic respiration takes place
• less energy released for metabolic processes
or less energy released so organs cannot function as well
• lactic acid produced (during anaerobic respiration) causes
muscle fatigue
Frequent infections
• fewer white blood cells / phagocytes / lymphocytes
• so fewer antibodies produced or less phagocytosis
• so fewer pathogens / bacteria / viruses killed
Bleeding
• fewer platelets
• so blood does not clot as easily
For Level 3, reference to all three symptoms must be made.
07.4 anti-B antibodies in patient / 1 AO3
receiver / recipient
will bind to type B antigens on
20 person’s / donor’s red blood
cells
(so) red blood cells clump allow (so) red blood cells clump 1 AO3
together and are wider than together and capillaries burst
capillaries
or
(so) red blood cells clump
together and block capillaries
(so) cells have reduced supply ignore references to energy 1 AO2
of oxygen / glucose
or
(so) cells can’t respire 4.2.2.3
if no other mark awarded allow 4.3.1.6
antibodies from patient and
antigens from donor are
matching / complementary
shapes for 1 mark
07.5 no antigens (on type O red 1 AO3
blood cells) 4.2.2.3
4.3.1.6
(so) antibodies cannot bind allow no clumping (of red blood 1
(to the antigens / red blood cells)
cells)
07.6 hepatitis C infection 1 AO3
4.2.2.3
4.3.1.1
07.7 no / less bile reaches the small ignore less / no bile produced 1 AO3
intestine
(so) less / no emulsification of allow correct description of 1 AO1
fat emulsification
do not accept reference to
chemical digestion
(so) smaller surface area for 1 AO1
lipase to break down fat
pH of small intestine is not allow pH of small intestine is 1 AO2
neutralised / alkaline acid / low
(so) lipase is not at its optimum pH (of small intestine) is not 1 AO2
pH to break down fat suitable for lipase to break down 4.2.2.1
fat
Total 19
How to answer it
Tumours, Blood Components, Transfusions & Digestion
This question assesses core understanding across organisation and non-communicable diseases:
- Definition of tumours and evidence for malignant spread (metastasis).
- Functions of blood components (red blood cells, white blood cells, platelets) linked logically to systemic symptoms.
- Antigen-antibody interactions in ABO blood groups and the mechanical consequences of blood clumping.
- Comparing probabilities presented in standard form, ratios, and percentages.
- The biological role of bile (neutralisation and emulsification) and lipase action in fat digestion.
Cellular Basis of Tumour Formation
Describe what happens to cells when a tumour forms.
✅ Mark Scheme Answer
- Cells divide / grow abnormally or uncontrollably.
🧠 Exam Technique
Always mention cell division (mitosis) paired with the idea of losing control. Stating merely "cells clump together" describes what you see, not the biological process.
❌ Common Error
"A mutation happens": While DNA mutations cause cancer, the mark scheme specifically ignores "mutation" because the question asks what happens to the cells themselves (uncontrolled division).
Identifying Malignancy from Anatomical Diagrams
What evidence is there in Figure 11 to suggest that the tumour in the lung is malignant?
✅ Mark Scheme Answer
Any one from:
- The tumour has spread to other parts / organs of the body.
- It has spread to the liver (or lung).
- It has formed a secondary tumour (or metastasised).
💡 Key Knowledge
Benign vs Malignant:
- Benign: Contained within a membrane; does not invade other tissues.
- Malignant: Cells break off and travel via the blood/lymphatic system to invade neighbouring tissues and form secondary tumours.
Low Blood Components & Clinical Symptoms
Explain how a very low number of blood components in the body can cause tiredness, frequent infections, and persistent bleeding.
✅ 1. Tiredness (Red Blood Cells)
- Fewer red blood cells means less haemoglobin.
- Less oxygen is transported around the body.
- Less aerobic respiration occurs / less energy is released for cellular work.
- Body switches to more anaerobic respiration, leading to lactic acid buildup and muscle fatigue.
✅ 2. Frequent Infections (White Blood Cells)
- Fewer white blood cells (lymphocytes and phagocytes).
- Fewer antibodies produced and less phagocytosis occurring.
- Fewer pathogens (bacteria or viruses) destroyed / killed.
✅ 3. Persistent Bleeding (Platelets)
- Fewer platelets (cell fragments).
- Blood cannot clot as easily / quickly at wounds.
🧠 Exam Technique: Chain of Causation
Top students structure answers with explicit causal chains: Component deficit → Mechanistic consequence → Cellular impact → Symptom.
❌ Common Misconceptions
- Saying respiration "produces / creates energy" (Energy cannot be created; it is released).
- Failing to link all three symptoms, instantly capping marks at Level 2 (max 4 marks).
ABO Blood Transfusion Incompatibility
It is dangerous for a patient with blood group A to receive red blood cells from a donor with blood group B. Explain why.
✅ Mark Scheme Breakdown (3 Marks)
- Mark 1: Patient's anti-B antibodies bind to the type B antigens on the donor's red blood cells.
- Mark 2: This causes red blood cells to clump together, which block capillaries (or clumped cells are wider than capillaries / burst capillaries).
- Mark 3: Downstream body cells receive a reduced supply of oxygen / glucose (or cells cannot respire).
💡 Interpreting the Data Provided
Figure 12 provides exact clues:
- Group A blood contains anti-B antibodies.
- Group B cells carry type B antigens.
- Red blood cells are ~8 μm, but capillary lumens are ~10 μm. A clump of several 8 μm cells physically jams in a 10 μm tube!
❌ Examiner Warning
Do NOT write "cells have no energy" for Mark 3. The mark scheme explicitly states: ignore references to energy. You must specify reduced supply of oxygen / glucose or an inability to respire.
Group O as the "Universal Donor"
Explain why blood group O red blood cells can be given to patients with any blood group.
✅ Mark Scheme Answer
- Mark 1: Group O red blood cells have no antigens on their surface.
- Mark 2: Therefore, recipient's antibodies cannot bind to the cells (so no clumping occurs).
🧠 Exam Technique
Check Figure 12 carefully: the Group O red blood cell surface is completely smooth with no shape tags attached. Always identify what is missing (antigens) and what reaction is prevented (antibody binding / agglutination).
Comparing Transfusion Risk Probabilities
Which risk has the lowest probability of occurring?
📐 Step-by-Step Conversion to Standard Form / Decimals
- Allergic reaction: 0.9% = 0.009 = 9.0 × 10⁻³
- Hepatitis B: 1 in (3 × 10⁵) = 1 / 300,000 ≈ 0.00000333 = 3.33 × 10⁻⁶
- Kidney damage: 1 in 70,000 ≈ 0.0000143 = 1.43 × 10⁻⁵
- Hepatitis C: 6.7 × 10⁻⁷ = 0.00000067 = 0.67 × 10⁻⁶
Comparing powers of 10: 10⁻⁷ is ten times smaller than 10⁻⁶ .
Since 0.67 × 10⁻⁶ < 3.33 × 10⁻⁶ , Hepatitis C is clearly the lowest.
✅ Correct Box to Tick
☑ Hepatitis C infection
❌ Common Math Trap
Looking at the coefficient alone ( 6.7 vs 1 in 300,000 ) or misreading negative powers. Remember that a larger negative exponent ( 10⁻⁷ vs 10⁻⁵ ) means a significantly smaller probability!
Gall Bladder Obstruction & Fat Digestion
A person has a tumour blocking the tube leading from the gall bladder to the small intestine. Explain why this person would have difficulty digesting fat.
✅ Full Mark Scheme Breakdown (5 Marks)
- Mark 1: No / less bile reaches the small intestine.
- Mark 2: Fat is not emulsified (large fat droplets are not broken down into smaller droplets).
- Mark 3: Lipase has a much smaller surface area of fat to work on.
- Mark 4: Stomach acid is not neutralised, so the small intestine remains acidic / not alkaline.
- Mark 5: Lipase is not at its optimum pH to break down fat effectively.
💡 Dual Action of Bile
Always remember bile does two distinct jobs in digestion:
- Physical: Emulsifies fats (increases surface area for lipase).
- Chemical/pH: Neutralises hydrochloric acid from the stomach to create an alkaline environment (~pH 7–8) ideal for digestive enzymes.
❌ Severe Penalties to Avoid
- "No bile is produced": The mark scheme says ignore less / no bile produced. Bile is made in the liver, not the gall bladder! The blockage only stops bile reaching the small intestine.
- "Bile digests fat chemically": Bile is NOT an enzyme. Never say bile breaks down fat into fatty acids and glycerol. Only lipase does that.
Topics
Biology · B1: Cell Biology · B2: Organisation · B3: Infection and Response · B4: Bioenergetics
Question and mark scheme from the AQA GCSE Biology examination, Biology Paper 1 (Higher), November 2021. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.