AQA GCSE Biology Biology Paper 2 (Foundation), June 2022: Question 10

✅ Correct Answer

Any single value in the range of 1.1 to 2.0 hours (e.g. 1.5 hours, 1.7 hours).

💡 Key Knowledge

A meal is eaten at 0.8 hours. Carbohydrates are digested into glucose and absorbed into the bloodstream, peaking at ~1.7 hours. The pancreas detects this rise and releases insulin into the blood to lower glucose back to normal levels.

🧠 Exam Technique

Do not pick the exact moment food was eaten. It takes time for food to be digested and absorbed. Insulin is only secreted at high levels while blood glucose is elevated above normal baseline (~4.3 mmol/dm³).

❌ Common Errors

• Choosing a time before the meal (e.g. 0.5 hours).
• Choosing a time after glucose has returned to resting baseline (e.g. 3.0 hours or 4.0 hours).

✅ Correct Answer

Effect:

• Lowers / decreases blood glucose concentration [1 mark]

Explanation:

• Glucose is taken into cells / converted into glycogen / used in respiration [1 mark]
• By liver cells / muscle cells [1 mark]

💡 Key Knowledge

Insulin acts as a chemical messenger:

• Produced by: Pancreas
• Target organs: Liver and muscles
• Action: Stimulates cells to absorb glucose from the blood and convert excess soluble glucose into insoluble glycogen for storage.

🧠 Exam Technique

To gain all 3 marks, you must state: 1) the overall effect, 2) the fate of glucose (uptake or conversion to glycogen), and 3) the specific target site (liver or muscle cells).

❌ Common Misconceptions

• Name confusion: Confusing glycogen (the storage carbohydrate) with glucagon (the hormone that raises glucose).
• Vaguely stating "insulin breaks down glucose" or "insulin eats glucose" (insulin is a signalling hormone, not an enzyme).
• Forgetting to name the target organs (liver / muscles).

✅ Correct Answer

Tick: Underweight [1 mark]

🧠 Reading the Graph

• Locate height = 1.75 m on the vertical y-axis.
• Move horizontally to a body mass of 52 kg on the horizontal x-axis.
• The intersection point sits inside the leftmost region labelled Underweight (the healthy zone at 1.75 m only begins at ~57 kg).

✅ Correct Answer

Range from 67.5 kg to 90 kg [1 mark]

(Examiners allow 67 to 68 kg for lower boundary; 90 to 90.5 kg for upper boundary)

📐 Step-by-Step Reading

1. Find 1.9 m on the vertical axis (Height).
2. Follow the horizontal gridline across into the Healthy weight band.
3. Read the left boundary of healthy weight: exactly halfway between 60 and 75, which is 67.5 kg.
4. Read the right boundary of healthy weight: it meets the vertical gridline at 90 kg.

❌ Common Errors

Misreading axis scales. Notice that major grid lines on the x-axis go up in increments of 10 or 15 kg (40, 50, 60, 70, 80, 90...). Pay careful attention to the division spacing.

✅ Correct Answer

Give any two comparative points:

• Person C has higher blood glucose (than the non-diabetic mean) [1 mark]
• Person C has higher blood insulin (than the non-diabetic mean) [1 mark]

Quoting numbers comparatively is accepted (e.g. glucose is 9.56 vs 4.51 mmol/dm³).

💡 Biological Reason

In Type 2 diabetes, the pancreas produces insulin (often in larger amounts: 24.32 vs 14.83), but the body's target cells resist or fail to respond to it. Because cells don't respond, glucose remains trapped in the blood, causing elevated blood glucose (9.56 vs 4.51).

❌ Common Errors & Examiner Warnings

• Mentioning cholesterol: The mark scheme explicitly states: "do not accept higher cholesterol". Cholesterol is a lipid linked to cardiovascular disease, not a diagnostic criterion for diabetes.
• Failing to compare: Simply writing "glucose is 9.56" without stating that it is higher than the mean scores 0 marks. Data must be comparative.

✅ Correct Answer

Any two from:

• Do (more) exercise / increase physical activity [1 mark]
• Eat less carbohydrate / less sugar (or follow a low-carbohydrate diet) [1 mark]
• Eat less fat / reduce total calorie intake / lose weight [1 mark]

🧠 Exam Technique: Be Specific!

GCSE examiners reject vague answers when asking about diet. Do NOT write:

• "Eat a healthy diet" ❌ (Ignored)
• "Have a balanced diet" ❌ (Ignored)

Always name the nutrient you need to reduce: sugar, carbohydrates, or fat.

💡 Why Exercise Works

Physical exercise forces muscle cells to respire faster, taking up glucose directly from the bloodstream without needing as much insulin. It also helps reduce obesity, which is the primary risk factor for insulin resistance.