Disciplinary Ideas Of Biology

Permanent vacuole - a large vacuole in plant cells that stores cell sap and helps maintain turgor pressure.

Specialisation (cell specialisation) - when a cell develops particular structures suited to a specific function.

Organelle - a specialised structure inside a cell that has a particular role.

Active Recall

Cell - __________________________________________________

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Nucleus - __________________________________________________

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Cell wall - __________________________________________________

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Chloroplast - __________________________________________________

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Permanent vacuole - __________________________________________________

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Specialisation (cell specialisation) - __________________________________________________

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Organelle - __________________________________________________

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Worked Examples

Example 1: Comparing plant and animal cells (straightforward)

Question scenario: State one feature present in plant cells but absent in animal cells.

• Identify a plant-only structure you know: chloroplast, cell wall, or permanent vacuole.

• Choose one and state its absence in animal cells.

• Link to function if asked (often: chloroplast → photosynthesis).

Answer (example): A plant cell has a cell wall; animal cells do not.

Now you try:

State two features present in plant cells but absent in animal cells.

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Example 2: Structure → function (medium)

Question scenario: A cell has many mitochondria. Explain what this suggests about its function.

• Mitochondria are the site of aerobic respiration (releasing energy).

• More mitochondria means the cell needs more energy.

• State a likely function: active transport, movement, or synthesis of substances.

Answer (example): It likely has a high energy demand, so the cell probably carries out active processes requiring ATP.

Now you try:

A cell has a large permanent vacuole. Explain how this helps the cell function.

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Example 3: Exam-style combined comparison (more complex)

Question scenario: Compare transport in plant and animal cells using vacuole information.

• Plant cells typically have a permanent vacuole that stores cell sap.

• Animal cells have smaller vacuoles and do not usually have a single permanent vacuole.

• For plant cells, the vacuole helps maintain turgor pressure, supporting the cell for transport of materials across the cell membrane.

Answer (example): The plant vacuole supports the cell and helps maintain turgor, which supports efficient functioning; animal cells rely more on other cytoplasmic arrangements rather than turgor.

Now you try:

Explain one similarity and one difference between plant and animal cell vacuoles in terms of function.

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Practice Questions

• (Easy) Describe the role of the nucleus in a eukaryotic cell.

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• (Easy) Name one structure found in plant cells but not in animal cells.

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• (Medium) Compare plant and animal cells by listing three differences.

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• (Medium) Explain how cell specialisation supports function in one example you choose (plant or animal).

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• (Hard) A cell has a large surface area and many mitochondria. Explain why these features are useful for its function.

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• (Hard) An organism is observed to have chloroplasts. Explain what this suggests about the type of cell and the likely function of the organism’s cells.

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Answer Key

• Controls cell activities by containing genetic material (DNA).

• Any one: cell wall, chloroplasts, or permanent vacuole.

• Any three correct differences (e.g., cell wall

, mitochondria number, vacuole size, or shape).

• Example must link a specialised structure to a specific function (e.g., ciliated cells for moving mucus; chloroplasts for photosynthesis; root hair cells for absorption).

• Large surface area increases diffusion rate; many mitochondria increase ATP supply for active processes.

• Chloroplasts indicate plant cells (or algae). Likely function: photosynthesis to make glucose.

Exam Tips & Common Mistakes

• Confusing cell structures: don’t mix up mitochondria (respiration) with chloroplasts (photosynthesis).

• Saying “cells make energy” without specifying: the mark usually needs the process (respiration in mitochondria; photosynthesis in chloroplasts).

• Forgetting the comparison: for plant vs animal, include at least one structural difference (cell wall, chloroplasts, permanent vacuole).

• Vague specialisation: “specialised for transport” is weak; name the structure and the exact function (e.g., root hair cells for absorption).

• Examiner focus for longer answers: use “structure → feature → function” and add one extra detail (surface area, turgor, ATP, pigments).

Quick Reference

How to answer “structure supports function”

• Identify the structure (e.g., root hair, ciliated cell, chloroplast).

• State the key feature (e.g., large surface area, cilia movement, chlorophyll pigment).

• Link to the function (e.g., absorption, moving mucus, photosynthesis).

• Use correct direction words: “helps maintain” / “increases” / “enables”.

Mnemonic (to remember the main plant vs animal differences)

• WCVP: W all, C hloroplasts, V acuole (permanent), P ermanent (plant) vs animal typically lacks these.

Absolute essentials

• Plant cells: cell wall, chloroplasts, permanent vacuole (turgor).

• Animal cells: no cell wall, no chloroplasts, vacuole not usually permanent.

• Nucleus controls cell activities; mitochondria release energy for respiration.

• Specialisation means structure matches function.

Confidence Check

• I can describe how the nucleus controls cell activities. [ ] 1 [ ] 2 [ ] 3 [ ] 4 [ ] 5

• I can compare plant and animal cells using at least three differences. [ ] 1 [ ] 2 [ ] 3 [ ] 4 [ ] 5

• I can explain how specialisation supports function using one named example. [ ] 1 [ ] 2 [ ] 3 [ ] 4 [ ]

End of chapter one. 7 more chapters in the full book.