b3 transport in cells
4 detailed 50-minute lessons with teaching scripts, worked examples, parent guides, and assessment criteria.
Lesson Overview
Total Lessons: 4
Tier: Foundation and Higher
Duration: 50 minutes per lesson (200 minutes total)
Exam Boards: AQA, Edexcel, OCR, Eduqas, CCEA
Tier: Foundation and Higher
Duration: 50 minutes per lesson (200 minutes total)
Exam Boards: AQA, Edexcel, OCR, Eduqas, CCEA
Learning Objectives
- Explain the key ideas of b3 transport in cells
- Apply b3 transport in cells to exam-style questions
- Develop independent study skills
- Build cross-topic connections
Prerequisites
- Read the revision notes for b3 transport in cells first (GCSE Revise summary)
- Key vocab to pre-teach: Substances move in and out of cells
- Basic skills: reading the summary notes and answering the practice questions there
Materials & Equipment
- Exercise book, coloured pens
- Scientific calculator
- Ruler
- Printed revision notes (link below)
- Internet for videos (see Resources)
Lesson 1: Introduction: b3 transport in cells
Duration: 50 minutes
Starter Activity (5 minutes)
Quick Recall
Write down everything you already know about b3 transport in cells. Then check against the key terms: Substances move in and out of cells. Use a mini-whiteboard or paper.
Main Content (35 minutes)
Parent/Teacher Guide:
Before lesson: Read the script below. Pre-teach key vocab: Substances move in and out of cells.
If stuck: Re-read the revision notes (link above), then break the content into smaller steps.
Extension: See the Stretch & Challenge ideas in Lesson 4.
Before lesson: Read the script below. Pre-teach key vocab: Substances move in and out of cells.
If stuck: Re-read the revision notes (link above), then break the content into smaller steps.
Extension: See the Stretch & Challenge ideas in Lesson 4.
Teaching Script (35 mins):
Mins 0-5 - Hook: "Today: b3 transport in cells. By the end you will be able to answer exam questions on it unaided. It connects to the rest of Combined Science (Trilogy) because the ideas here recur across the spec."
Mins 5-20 - Direct Instruction: Work through the core ideas below one at a time; after each, ask your student to explain it back in their own words.
Mins 20-30 - Guided Practice: Model the worked example together, then let your student attempt the first practice question with guidance.
Mins 30-35 - Independent Practice: 2-3 practice questions from Lesson 3 below, with immediate feedback.
Mins 0-5 - Hook: "Today: b3 transport in cells. By the end you will be able to answer exam questions on it unaided. It connects to the rest of Combined Science (Trilogy) because the ideas here recur across the spec."
Mins 5-20 - Direct Instruction: Work through the core ideas below one at a time; after each, ask your student to explain it back in their own words.
Mins 20-30 - Guided Practice: Model the worked example together, then let your student attempt the first practice question with guidance.
Mins 30-35 - Independent Practice: 2-3 practice questions from Lesson 3 below, with immediate feedback.
First Look
Start with the revision notes summary, then attempt: Define diffusion. (2 marks)
Plenary (5 minutes)
Check Out
Your student states one thing they learned and one question they still have about b3 transport in cells.
Lesson 2: Core Concepts: b3 transport in cells
Duration: 50 minutes
Starter Activity (5 minutes)
Review Previous Lesson
Quick recap: write 3 key points from Lesson 1 on b3 transport in cells. Check them against the notes below.
Main Content (35 minutes)
Substances move in and out of cells: by three main methods: diffusion, osmosis, and active transport. Which method is used depends on the type of substance, the direction it needs to move, and whether energy is required.
| Term | Meaning | Example |
|---|---|---|
| Diffusion | Gases and dissolved substances | High to low concentration |
| Osmosis | Water only | High to low water concentration |
| Active transport | Dissolved substances | Low to high concentration |
| 0.0 | +18.2 | +17.9 |
| 0.2 | +10.5 | +10.1 |
| 0.4 | +2.3 | +2.1 |
| 0.6 | −6.0 | −5.8 |
| 0.8 | −13.2 | −12.9 |
Practice (10 minutes)
Q: Define diffusion. (2 marks)
Answer: Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration, down the concentration gradient.
Plenary (5 minutes)
Explain Back
Your student teaches the key points back to you without looking. Fill any gaps immediately.
Lesson 3: Application: b3 transport in cells
Duration: 50 minutes
Starter Activity (5 minutes)
Quick Recall
Recall the key terms: Substances move in and out of cells. Define each in one sentence.
Main Content (35 minutes)
Parent/Teacher Guide: Let your student attempt each question alone first, then compare with the model answer. Award method marks for correct working even if the final answer is wrong.
Q1: Define diffusion. (2 marks)
Answer: Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration, down the concentration gradient.
Q2: Define osmosis. (2 marks)
Answer: Osmosis is the movement of water molecules from a region of higher water concentration to a region of lower water concentration through a partially permeable membrane.
Q3: Explain the difference between diffusion and active transport. (2 marks)
Answer: Diffusion moves substances down the concentration gradient and does not require energy. Active transport moves substances against the concentration gradient and requires energy from respiration.
Q4: A potato cylinder has an initial mass of 6.0 g and a final mass of 6.9 g after being placed in a dilute sugar solution. Calculate the percentage change in mass. (2 marks)
Answer: Percentage change = ((6.9 - 6.0) ÷ 6.0) × 100 = (0.9 ÷ 6.0) × 100 = +15%
Q5: Explain why root hair cells use active transport to absorb minerals from the soil. (3 marks)
Answer: Root hair cells use active transport because the concentration of minerals in the soil is lower than inside the cell. Minerals cannot diffuse in (they would diffuse out). Active transport uses energy from respiration to move minerals against the concentration gradient into the cell.
Q6: Explain why a plant cell does not burst when placed in a very dilute solution, but an animal cell can. (3 marks)
Answer: When placed in a dilute solution, water enters both cells by osmosis. The plant cell has a rigid cellulose cell wall that provides support and prevents the cell from bursting - the cell becomes turgid instead. The animal cell has no cell wall, so as water enters, the cell swells and can burst (lysis).
Plenary (5 minutes)
Error Review
Review any questions answered incorrectly. Identify whether the error was knowledge, method, or reading the question.
Lesson 4: Exam Practice: b3 transport in cells
Duration: 50 minutes
Starter Activity (5 minutes)
Command Words
Review what these command words require: state (one point), describe (say what happens), explain (say why), compare (both sides), evaluate (judgement).
Main Content (35 minutes)
Exam-Style Question
Attempt a past-paper style question on b3 transport in cells from the exam board past paper finder (see Resources), then mark it against the scheme.
Exam Tips: Always say "partially permeable membrane" when defining osmosis - you lose marks without it | For osmosis, say "water concentration" not just "concentration" - be specific | Remember: diffusion and osmosis are passive (no energy), active transport needs energy | In the osmosis practical, always BLOT DRY before measuring final mass | Percentage change can be positive OR negative - the sign tells you the direction | SA:V ratio questions often appear - remember small = high ratio = efficient exchange | When asked to "explain" osmosis, mention both the direction AND the membrane
Common Errors: Watch Out! 1. Wrong: Osmosis is just water diffusion Correct: Osmosis specifically requires a partially permeable membrane — without it, water movement is just diffusion 2. Wrong: Water moves to the side with more water Correct: Water moves from a dilute solution (more water, fewer solutes) to a concentrated solution (less water, more solutes) through a partially permeable membrane
AO3 - Reasoning & Interpretation: Analysis and Evaluation A student obtained the following results from the osmosis practical: Concentration (M) % change (Repeat 1) % change (Repeat 2) % change (Repeat 3) 0.0 +18.2 +17.9 +12.1 0.2 +10.5 +10.1 +10.3 0.4 +2.3 +2.1 +2.5 0.6 −6.0 −5.8 −5.9 0.8 −13.2 −12.9 −13.0 (a) Identify the anomaly and suggest a cause. (b) Estimate the concentration inside the potato cells. Answers: (a) The value +12.1 at 0.0 M is anomalous — the other two repeats are close (+18.2, +17.9). Likely cause: the cylinder was not blotted dry properly, or excess surface water was included in the mass measurement. (b) The isotonic point (where % change ≈ 0) is between 0.4 M and 0.6 M, so the concentration inside the
Stretch & Challenge (Grade 8-9):
- Synoptic links: explain how b3 transport in cells connects to another Combined Science (Trilogy) topic you have studied
- Real-world: research one real-world use or example of b3 transport in cells
- Critical: "What are the limitations of the models used in b3 transport in cells?"
Plenary (5 minutes)
Assessment Criteria
- Got it: Confident explanation + correct worked examples
- Getting there: Main points OK, needs support with detail
- Not yet: Confused on key concepts - re-run Lesson 2
Homework & Consolidation
- Consolidation: Re-answer any Lesson 3 practice questions answered incorrectly (20 mins)
- Retrieval: Write flashcards for the key terms: Substances move in and out of cells (10 mins)
- Exam practice: One past-paper question on b3 transport in cells from the board websites (15 mins)
- Extension: Explain b3 transport in cells to someone else in your own words (10 mins)