Cambridge O Level Biology 509011MJ Revision Paper 1 Variant 1 Q1 - 17 MCQ solved

Описание: 1) Function of the Plant Cell (Root Hair Cell)
✅ Correct Answer: D – To take in water
🔬 System Explanation

Cell type: Root hair cell
Specialisation: Long extension increases surface area
Function: Absorbs water by osmosis and mineral ions by active transport

❌ Why others are wrong

A – Xylem transports water/minerals
B – No chloroplasts underground
C – CO₂ intake occurs in leaves

🔑 Keywords

Root hair cell, surface area, osmosis, mineral ions, absorption

⚠️ Common Mistake

Confusing root hair cells with xylem vessels.

🎯 Learning Outcome

Identify specialised plant cells and link structure to function.

⚡ 2) Active Transport – Incorrect Statement
✅ Correct Answer: A
🔬 System Explanation

Active transport:
• Moves substances against concentration gradient
• Requires ATP (energy)
• Occurs in plants AND animals
• Happens across partially permeable membranes

🔑 Keywords

Active transport, ATP, concentration gradient, membrane proteins

⚠️ Common Mistake

Thinking active transport only happens in plants.

🎯 Learning Outcome

Differentiate diffusion, osmosis, and active transport.

🧪 3) Effect of pH on Amylase Reaction Time
✅ Correct Answer: Graph D
🔬 System Explanation

• Enzymes have an optimum pH
• At optimum → shortest reaction time
• Far from optimum → enzyme denatures → longer time
• Graph shape = U-shaped curve

🔑 Keywords

Optimum pH, enzyme activity, denaturation, reaction rate

⚠️ Common Mistake

Forgetting the question asked about time, not rate.

🎯 Learning Outcome

Interpret enzyme graphs correctly.

🍃 4) Where Does Photosynthesis Occur?
✅ Correct Answer: B (E and F)
🔬 System Explanation

Photosynthesis occurs in:
• Palisade mesophyll (main site)
• Spongy mesophyll (some photosynthesis)

Not in:
• Vascular bundles
• Epidermis (usually no chloroplasts)


Chloroplasts, mesophyll, palisade layer

⚠️ Common Mistake

Choosing vascular bundle because it is central.

🎯 Learning Outcome

Identify photosynthetic tissues in leaf sections.

💨 5) Water Uptake – Potometer Graph
✅ Correct Answer: Graph B
🔬 System Explanation

• Measures water uptake (proxy for transpiration)
• First 10 min → steady slope
• After fan → increased transpiration
• Graph becomes steeper

🔑 Keywords

Transpiration, air movement, evaporation, potometer

⚠️ Common Mistake

Thinking curve should bend instead of straight steeper line.

🎯 Learning Outcome

Interpret rate changes from graph slope.

🌬 6) Gas Exchange Data – Incorrect Statement
✅ Correct Answer: C
🔬 System Explanation

Inspired vs Expired:

Gas Inspired Expired (Rest) Expired (Exercise)
O₂ 21% 16% 14.5%
CO₂ 0.04% 5.04% 6.54%

Ratio O₂ : CO₂ in inspired air:
21 ÷ 0.04 = 525 (NOT 52.5)

🔑 Keywords

Respiration, oxygen uptake, carbon dioxide release

⚠️ Common Mistake

Calculation errors with decimals.

🎯 Learning Outcome

Analyse respiratory data accurately.

❤️ 7) Heart Circulation – Two Complete Circuits

One complete circuit:
Right atrium → Right ventricle → Left atrium → Left ventricle
= 4 chambers

Two complete circuits:
4 × 2 = 8 chambers passed

✅ Final Answer: 8
🔬 System Explanation

Human circulation is double circulation:
• Pulmonary circuit
• Systemic circuit

Each circuit passes through 4 chambers.

🔑 Keywords

Double circulation, atrium, ventricle, pulmonary, systemic

⚠️ Common Mistake

Counting only one side of heart.

🎯 Learning Outcome

Understand pathway of blood through heart.

📘 Complete System Covered in This Revision

This Paper 1 variant tested:

• Cell specialisation
• Membrane transport
• Enzymes
• Photosynthesis
• Transpiration
• Gas exchange
• Human circulation

These are core high-frequency topics in:
• O Level 5090
• IGCSE 0610
• Edexcel IGCSE
• Oxford AQA

🎯 Helpful For

• Quick MCQ revision
• Last-minute exam prep
• Strengthening weak topics
• Understanding graph interpretation


5090/11/m/j biology solved
O level biology paper 1 revision
root hair cell function MCQ
active transport incorrect statement
amylase pH graph question
potometer graph explained
gas exchange calculation question
double circulation MCQ

📈 Learning Outcomes Summary

After this revision, you can:

✔ Identify specialised plant cells
✔ Explain membrane transport mechanisms
✔ Interpret enzyme graphs
✔ Analyse transpiration data
✔ Calculate respiratory differences
✔ Understand double circulation

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