AQA GCSE Combined Science: Trilogy Biology Paper 1 (Higher), 2022: Question 6

✅ Correct answers

• 06.1: The heart is an organ because it is made of different tissues that work together for a specific function.
• 06.2: A leak in the valve lets some blood flow backwards, so less oxygenated blood reaches the body.
• 06.3: For this woman, biological valves avoid lifelong anti-clotting drugs, which is helpful if she wants children and does extreme sports.

🧠 Exam technique

• Use the command word: “why”, “explain”, and “describe” need different depth.
• For 4-mark explanations, chain cause → effect → consequence.
• Compare biological and mechanical valves using the given context: pregnancy, sports, and medication.

❌ Common errors

• Saying “an organ is a body part” without mentioning tissues.
• Describing blood flowing into the wrong chamber instead of backflow from the valve leak.
• For 06.3, giving only advantages or only disadvantages: that limits the mark.

✅ Correct answer

The heart is made up of different tissues that perform specific functions.

💡 Key knowledge

• An organ is a group of different tissues.
• The tissues work together to carry out a function.
• For the heart, the function is pumping blood around the body.

🧠 Exam technique

For a 1-mark definition question, give the exact biology idea rather than a vague description. “Different tissues working together” is the safest wording.

✅ Mark-point answer

• Some blood would flow back into the ventricle / heart.
• So less oxygenated blood would be pumped to the body.
• Cells would have less oxygen for aerobic respiration.
• The person would become tired / out of breath / have less energy.

💡 Key knowledge

• Valves keep blood flowing in one direction.
• If a valve leaks, it does not fully close.
• That means not all blood leaves the ventricle or heart chamber.
• Reduced oxygen supply means less aerobic respiration in cells.

🧠 How marks are awarded

Examiners credited each linked stage:

• backflow happens
• less oxygenated blood is pumped out
• cells need oxygen for respiration
• result: tiredness / breathlessness / less energy

❌ Common errors

• “Blood would flow into the right ventricle” — this was not the accepted idea.
• Talking only about glucose instead of oxygen.
• Saying “less energy produced” is too vague unless linked to respiration.
• Missing the final effect on the person, such as being tired or out of breath.

✅ Strong answer points

Biological valves would be a good choice because:

• They allow blood to flow normally and have a reduced risk of blood clots.
• This is safer for pregnancy and birth because there is less risk of clotting problems or bleeding problems from anti-clotting drugs.
• She would not need to take anti-clotting drugs for life, which is better for someone doing extreme sports because serious bleeding after an accident is less likely.
• There is also less risk of problems for a foetus / baby from drugs.

💡 Key knowledge

Biological valves:

• Come from animals or human donors.
• Work normally with blood flow.
• Wear out over time.
• Usually do not need lifelong anti-clotting drugs.

Mechanical valves:

• Are synthetic.
• Can last a long time.
• May cause blood clots.
• Need anti-clotting drugs for life.

🧠 What top answers did

• Gave both advantages and disadvantages of biological valves.
• Linked the decision to the woman’s lifestyle and future pregnancy.
• Compared against the mechanical valve idea, especially lifelong drugs and clotting risk.

❌ Common errors

• Only saying “biological valves are better” without explaining why.
• Forgetting the context of pregnancy and extreme sports.
• Repeating the same idea twice, such as clotting risk in two different sentences.
• Talking about surgery risks — these were not credited.

💡 Remember

• Organ: different tissues working together.
• Valves: stop backflow of blood.
• Leak: less oxygenated blood reaches the body.
• Biological valves: lower clotting risk, but wear out.
• Mechanical valves: last longer, but need lifelong anti-clotting drugs.

🧠 Best exam habit

When a question asks you to “explain”, always connect the biology to the outcome. The examiner is looking for linked ideas, not just a list.