AQA GCSE Combined Science: Trilogy Biology Paper 2 (Foundation), 2024: Question 2

💡 Key knowledge

• The pituitary gland, adrenal gland, and ovary are the glands labelled.
• Receptor cells detect changes in blood glucose concentration.
• Insulin is carried in the bloodstream.
• The main target organ for insulin here is the liver.
• Excess glucose is stored as glycogen.

🧠 Exam technique

• For 1-mark recall questions, give the exact key term.
• For graph questions, describe the trend first, then use data only if needed.
• For explanation questions, link the graph to insulin and blood glucose levels.

✅ Correct answers

Top label: pituitary gland

Middle label: adrenal gland

Bottom label: ovary

💡 Key knowledge

• The pituitary gland is in the brain.
• The adrenal glands sit on top of the kidneys.
• The ovaries are in the pelvis.

❌ Common errors

• Putting the labels in the wrong order.
• Writing testis instead of ovary.
• Choosing thyroid gland even though it is not one of the labelled organs here.

✅ Correct answer

Receptor cells

💡 Key knowledge

Receptor cells detect a change in conditions in the body. In this topic, they detect when blood glucose rises or falls.

❌ Common errors

• Coordinator cells is wrong — they control responses, they do not detect the change.
• Muscle cells do not detect blood glucose concentration.

✅ Correct answer

In the bloodstream / through the blood / via blood vessels

💡 Key knowledge

Insulin is a hormone, so it is carried in the blood to reach its target organ.

Allowed wording: in plasma or via blood vessels .

❌ Common errors

• Do not say it is carried by red blood cells or white blood cells.
• Do not say it is transported by the nervous system.

✅ Correct answer

Liver

💡 Key knowledge

The liver responds to insulin by taking up glucose and storing it as glycogen.

❌ Common errors

• Choosing small intestine or stomach — these are not the target organ here.

✅ Correct answer

Glycogen

💡 Key knowledge

Humans store excess glucose as glycogen in the liver and muscles.

❌ Common errors

• Cellulose is a plant cell wall material, not a human storage molecule.
• Protein is not the glucose store.

📐 Calculation steps

1. Read the value at 0 minutes: 5 arbitrary units.
2. Read the value at 60 minutes: 11 arbitrary units.
3. Find the change: 11 − 5 = 6.

Answer: 6 arbitrary units

🧠 Exam technique

• Always do final value − starting value.
• Include the unit if the question expects it: arbitrary units.
• If you cannot write the working on the line, use the graph values clearly.

❌ Common errors

• Using 60 − 0 instead of the glucose values.
• Writing the answer as 11 or 5 rather than the difference.
• Forgetting the unit arbitrary units.

✅ Correct answer

Blood glucose concentration increases and then decreases.

🧠 Exam technique

• Use trend words, not a long story.
• You can say it rises and then falls.
• If the graph levels off before falling, you can still describe the overall trend correctly.

❌ Common errors

• Only saying “it changes” is too vague.
• Giving lots of time values without describing the pattern does not score the mark.
• Writing “stays constant” is not enough because the graph clearly rises first.

✅ What a full-mark answer should say

Person A has a higher blood glucose concentration than the others and it stays high for longer / does not decrease much. This suggests there is less insulin or the body cells do not respond properly to insulin.

💡 Key knowledge

• Diabetes means blood glucose is not controlled properly.
• Insulin normally lowers blood glucose by helping cells take up glucose and the liver store it as glycogen.
• In Type 2 diabetes, body cells may not respond well to insulin.

❌ Common errors

• Just saying “Person A has diabetes” without evidence.
• Referring to the graph but not mentioning insulin.
• Confusing higher blood glucose with “more healthy”.

✅ Correct answers: any two

• Eat less carbohydrate / sugar or follow a low-carbohydrate diet.
• Eat less fat.
• Lose body mass / weight.
• Do more exercise.

💡 Key knowledge

Exercise and weight loss help cells respond better to insulin and reduce blood glucose levels. Cutting down on sugary foods helps prevent blood glucose rising as much after meals.

🧠 Exam technique

• Give two different lifestyle changes.
• Be specific: “eat less sugar” is better than just “go on a diet”.
• You can say increased exercise or more exercise.

❌ Common errors

• Take medicine/insulin was not accepted here because the question asks for lifestyle changes.
• Pancreas transplant is not a lifestyle change.
• “Go on a diet” alone is too vague unless you specify the type, e.g. controlled calorie diet.

📌 Quick recall list

• 02.1: pituitary gland, adrenal gland, ovary
• 02.2: receptor cells
• 02.3: bloodstream
• 02.4: liver
• 02.5: glycogen
• 02.6: 6 arbitrary units
• 02.7: increases then decreases
• 02.8: high glucose + less insulin / no response to insulin
• 02.9: eat less sugar/carbohydrate, eat less fat, lose weight, exercise more

🧠 How marks were awarded

• Most parts were simple 1-mark recall.
• Graph questions needed clear comparison and trend language.
• The explanation question needed both evidence and biology.