Cell BiologyExam Focus

How This Topic Appears in Exams

Part of Cell Transport — GCSE Biology

This exam focus covers How This Topic Appears in Exams within Cell Transport for GCSE Biology. Diffusion, osmosis, active transport, factors affecting transport, surface area to volume ratio, and practical investigations It is section 16 of 18 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.

Topic position

Section 16 of 18

Practice

18 questions

Recall

20 flashcards

📝 How This Topic Appears in Exams

Typical Question Types

"Define osmosis / diffusion / active transport" (1-2 marks) — memorise precise definitions. For osmosis: always mention water, partially permeable membrane, and direction (dilute to concentrated).
"Explain why [cell/structure] is adapted for..." (3-4 marks) — link the structural feature to its transport function. E.g., "The alveoli have a large surface area, which increases the rate of diffusion of oxygen into the blood."
Required practical questions (RPA2) — you may be asked to describe the method, identify variables, calculate percentage change in mass, or interpret a graph of results against salt concentration.
Calculation: percentage change in mass — expect at least 1 calculation question. Always show your working and include the % sign and +/− sign in your answer.
"Explain why active transport requires..." (2-3 marks) — must mention: against the concentration gradient, ATP, mitochondria.
6-mark extended response — may ask you to compare all three transport types or explain how the small intestine absorbs food using multiple transport mechanisms.

Key Exam Vocabulary

Always write "partially permeable membrane" — not just "membrane" or "semi-permeable membrane" (though semi-permeable is accepted).
For active transport, always include "against the concentration gradient" and "requires energy (ATP)".
When describing osmosis results, use turgid / flaccid / plasmolysed to pick up technical vocabulary marks.
For factors affecting diffusion, use "rate" — "the rate of diffusion increases" is better than "diffusion is faster".

Practice Questions for Cell Transport

Which statement best describes diffusion?

A. The movement of particles from a region of low concentration to high concentration
B. The net movement of particles from a region of high concentration to low concentration
C. The movement of water molecules through a partially permeable membrane
D. The movement of particles using energy from respiration

1 markfoundation

Explain how osmosis causes a plant cell to become plasmolysed when placed in a concentrated sugar solution.

3 marksstandard

Quick Recall Flashcards

Define diffusion

The movement of particles from an area of high concentration to an area of low concentration down a concentration gradient. No energy is required (passive process).

Define osmosis

The movement of water molecules from an area of high water concentration (low solute concentration) to an area of low water concentration (high solute concentration) through a semi-permeable membrane.