AQA GCSE Biology Biology Paper 1 (Higher), June 2022: Question 2

✅ Correct Answer

Either of the following:

• (cell) wall
• (large / permanent) vacuole

💡 Key Knowledge

• Fungal cells have: nucleus, cytoplasm, cell membrane, mitochondria, ribosomes, a vacuole, and a cell wall (made of chitin, not cellulose).
• Animal cells have: nucleus, cytoplasm, cell membrane, mitochondria, ribosomes. They lack a cell wall and permanent vacuole.

❌ Common Errors

• Writing chloroplast: Fungal cells never contain chloroplasts because they do not photosynthesise!
• The mark scheme notes: ignore "cellulose" (as fungal cell walls are chitin), but writing "cellulose cell wall" can risk losing the mark if contradictions are penalised. Keep it simple: cell wall.

🧠 Exam Technique

Carefully check the diagram provided (Figure 2). You can visibly identify the thick outer boundary (the cell wall), the inner cell membrane, a nucleus, and a large round central vacuole.

✅ Correct Answer

Tick: Rose black spot

💡 Key Knowledge: GCSE Pathogen Recall

• Gonorrhoea: Caused by a bacterium (STD).
• Malaria: Caused by a protist (vector: mosquito).
• Measles: Caused by a virus (spread by droplets).
• Rose black spot: Caused by a fungus (spread by water and wind).

❌ Common Errors & Examiner Traps

• Incompatible units: Dividing 90 ÷ 24 or 24 ÷ 90 without converting hours into minutes.
• Adding units: The mark scheme states: "do not accept if a unit is given" (e.g. writing "16 hours" or "16 minutes" instead of just 16).
• Confusing number of divisions with final cell count: The question asks how many times it divides (16), not how many cells are produced (2¹⁶).

Mark Breakdown:
• [1 mark] for correct working: (24 × 60) ÷ 90 or 24 ÷ 1.5
• [1 mark] for the correct final number: 16

✅ 02.4: Where is protein digested?

Tick: Stomach

✅ 02.5: Test for protein

Tick: Biuret reagent

💡 Quick Recall of Food Test Reagents

• Sugars (reducing): Benedict's reagent (heated in water bath → turns green/yellow/brick-red).
• Starch: Iodine solution (turns from orange-brown to blue-black).
• Lipids (fats): Ethanol (forms a white cloudy emulsion).
• Protein: Biuret reagent (turns purple).

❌ Common Misconceptions

• Thinking the liver digests food: The liver produces bile to emulsify fats and neutralise stomach acid, but digestion of food molecules does not happen inside the liver.
• Thinking the large intestine digests protein: Only water absorption takes place in the large intestine.

Model Paragraph Structure

1. Advantages of Meat-Free:
"Meat-free burgers have much less fat (5.2 g vs 16.0 g) and zero cholesterol compared to 120 mg in meat. High fat and cholesterol can build up fatty deposits in coronary arteries, causing coronary heart disease (CHD) or heart attacks. Meat-free also has more fibre (5.5 g vs 0.9 g), which aids digestion and prevents constipation."

2. Advantages of Meat Burgers:
"However, meat burgers contain more protein (14.0 g vs 9.0 g), which is essential for muscle growth and repair."

3. Missing Info & Overall Judgement:
"Both have similar carbohydrate levels for energy (around 15 g), but Table 3 lacks data on vitamins and minerals (such as iron). Overall, meat-free burgers are healthier for a balanced diet because they drastically reduce the risk of heart disease and obesity while still providing adequate protein."

❌ Common Errors in 6-Mark Questions

• Data copying without biology: Simply quoting "Meat has 16g fat and meat-free has 5.2g" without explaining why fat matters to health. Level 1 only!
• One-sided answers: Only praising meat-free burgers and completely ignoring the higher protein in meat burgers.
• No conclusion: Forgetting to give a final reasoned judgement on which is better for a balanced diet.