AQA GCSE Combined Science: Trilogy Biology Paper 1 (Foundation), 2024: Question 4

✅ Correct answer

Pain when urinating

This is the only option that matches the mark scheme.

💡 Key knowledge

• Gonorrhoea is a sexually transmitted infection.
• Common symptoms can include pain when urinating and unusual discharge.
• Some people may have no obvious symptoms.

🧠 Exam technique

For a tick-box question, read all options carefully. One mark = one correct tick only.

Choose the symptom that is specific to the infection, not a general illness sign.

❌ Common errors

• Damaged immune system is not a gonorrhoea symptom.
• Reduced body temperature is not correct.
• Students sometimes confuse symptoms of different diseases.

✅ Correct answer

Any one of these:

• Not all cases are reported or recorded.
• There may be false positives or false negatives.
• Some people may not know they have it.
• The figures may involve misdiagnosis.

💡 Key knowledge

• Reported case numbers are not always the same as the real number of infected people.
• Data in biology often depends on testing, diagnosis, and reporting.
• Population figures can be estimates, so disease rates may also be approximate.

🧠 Exam technique

Because it says “Suggest one reason”, give one clear reason only.

A short explanation is enough if it clearly shows why the data may be unreliable.

❌ Common errors

• Vague answers like “people lie” may not earn the mark.
• Do not just say “it is hard to count” unless you explain why.
• Top answers mentioned under-reporting or misdiagnosis.

✅ Correct answer

Bar chart

💡 Key knowledge

• The data is for different cities, so it is categorical data.
• Bar charts are best for comparing categories.
• Line graphs are usually for continuous data over time.
• Scatter graphs are for looking for correlation between two variables.

🧠 Exam technique

Ask: am I comparing groups, time, or two measurements?

Here, the cities are separate groups, so a bar chart is the clearest choice.

❌ Common errors

• Line graph is wrong because the cities are not in a continuous sequence.
• Scatter diagram is wrong because there is no pair of numerical variables to compare.

✅ Correct answer

To compare cities fairly because they may have different population sizes.

💡 Key knowledge

• Using a rate per 100 000 standardises the data.
• This lets you compare places with different population sizes properly.

🧠 Exam technique

The best answers say “to compare” and explain that the cities are different sizes.

That is enough for full marks in a 1-mark explain question.

❌ Common errors

• Just saying “so it looks nicer” does not answer the science question.
• Do not say it is because the number of cases is inaccurate — that is a different part.

✅ Correct answers

High fat diet

Smoking

Tick both of these for 2 marks.

💡 Key knowledge

• A high fat diet increases cholesterol levels and plaque formation.
• Smoking damages blood vessels and increases the risk of cardiovascular disease.
• Regular exercise and statins reduce risk, so they are not correct here.

🧠 Exam technique

There are two marks, so two correct ticks are needed.

Read every option carefully. Some answers are risk factors, and some are treatments or protective factors.

❌ Common errors

• Low blood glucose is not a plaque risk factor.
• Regular exercise lowers risk, so it is not correct.
• Taking statins is a treatment, not a cause.

✅ Correct answer

A stent

💡 Key knowledge

• A stent is a small tube inserted into an artery.
• It helps keep the artery open so blood can flow through more easily.
• Antibiotics do not treat plaque, because plaques are not caused by bacteria.

🧠 Exam technique

Look for the treatment that matches the cause of the problem.

Plaques in arteries are treated by opening the artery, not by using medicines for infection.

❌ Common errors

• A placebo has no active effect.
• An antibiotic treats bacterial infections, not blocked arteries.

✅ Correct answer

• The blockage means less or no blood flow to the heart muscle.
• This means less or no oxygen reaches the heart muscle cells.
• So there is less or no respiration, so the cells get less energy and die.

💡 Key knowledge

• Heart muscle needs a constant oxygen supply.
• Oxygen is needed for aerobic respiration.
• Respiration releases energy for cell function and survival.

🧠 Exam technique

For 3 marks, write a chain of explanation:

blocked artery → less blood → less oxygen → less respiration → less energy → cells die

Each linked step can earn a mark.

❌ Common errors

• Do not stop after saying “less oxygen”; you must explain the effect on respiration.
• Do not write about lactic acid unless you know the question wants it — it was not needed here.
• Top answers were short but linked clearly from blockage to cell death.

💡 High-scoring themes

• Correct factual recall: symptom, risk factors, treatment.
• Choosing the right graph for categorical data.
• Explaining why rates per population are better for comparison.
• Using a clear cause-and-effect chain in the heart question.

🧠 Mark-winning habits

• Use the exact idea the mark scheme wants.
• Keep answers precise and science-based.
• For explanation questions, connect each step logically.