b7 plant organisation
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 b7 plant organisation
- Apply b7 plant organisation to exam-style questions
- Develop independent study skills
- Build cross-topic connections
Prerequisites
- Read the revision notes for b7 plant organisation first (GCSE Revise summary)
- Key vocab to pre-teach: Plants are organised
- 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: b7 plant organisation
Duration: 50 minutes
Starter Activity (5 minutes)
Quick Recall
Write down everything you already know about b7 plant organisation. Then check against the key terms: Plants are organised. Use a mini-whiteboard or paper.
Main Content (35 minutes)
Parent/Teacher Guide:
Before lesson: Read the script below. Pre-teach key vocab: Plants are organised.
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: Plants are organised.
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: b7 plant organisation. 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: b7 plant organisation. 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: Name the plant tissue responsible for photosynthesis and describe two adaptations of its cells. (3 marks)
Plenary (5 minutes)
Check Out
Your student states one thing they learned and one question they still have about b7 plant organisation.
Lesson 2: Core Concepts: b7 plant organisation
Duration: 50 minutes
Starter Activity (5 minutes)
Review Previous Lesson
Quick recap: write 3 key points from Lesson 1 on b7 plant organisation. Check them against the notes below.
Main Content (35 minutes)
Plants are organised: into tissues, organs and transport systems, just like animals. Plant tissues include epidermal, mesophyll, xylem and phloem. Water and minerals are transported through xylem; sugars are transported through phloem. Transpiration drives the movement of water through the plant.
| Term | Meaning | Example |
|---|---|---|
| Epidermal tissue | Covers and protects surfaces of leaves, stems and roots | Thin, flat cells forming a continuous layer; covered by waxy cuticle on leaves to reduce water loss |
| Palisade mesophyll | Photosynthesis (main site) | Tall, column-shaped cells; packed with chloroplasts; positioned near upper surface of leaf for maximum light |
| Spongy mesophyll | Gas exchange within the leaf | Rounded, loosely-packed cells; large air spaces between cells allow gases (CO₂, O₂, water vapour) to diffuse freely |
| Xylem | Transports water and dissolved minerals from roots to leaves | Dead cells forming continuous hollow tubes; walls strengthened with lignin (waterproof and provides support); no cytoplasm or end walls |
| Phloem | Transports dissolved sugars (translocation) from leaves to growing and storage tissues | Living cells; sieve tube elements with perforated sieve plates; companion cells provide energy for transport |
| Roots | Anchor the plant; absorb water and minerals from soil | Root hair cells (increased surface area for absorption); xylem and phloem (transport) |
| Stems | Support the plant; transport water and sugars between roots and leaves | Xylem (water transport up); phloem (sugar transport both ways); structural tissue for support |
| Leaves | Photosynthesis; gas exchange | Palisade mesophyll (photosynthesis); spongy mesophyll (gas exchange); epidermal tissue with stomata (gas exchange and transpiration) |
Practice (10 minutes)
Q: Name the plant tissue responsible for photosynthesis and describe two adaptations of its cells. (3 marks)
Answer: Palisade mesophyll. Adaptation 1: Cells are tall and column-shaped, packed with chloroplasts to absorb maximum light for photosynthesis. Adaptation 2: Positioned near the upper surface of the leaf where light intensity is highest. (Also accept: closely packed to maximise the number of photosynthetic cells in the light path.)
Plenary (5 minutes)
Explain Back
Your student teaches the key points back to you without looking. Fill any gaps immediately.
Lesson 3: Application: b7 plant organisation
Duration: 50 minutes
Starter Activity (5 minutes)
Quick Recall
Recall the key terms: Plants are organised. 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: Name the plant tissue responsible for photosynthesis and describe two adaptations of its cells. (3 marks)
Answer: Palisade mesophyll. Adaptation 1: Cells are tall and column-shaped, packed with chloroplasts to absorb maximum light for photosynthesis. Adaptation 2: Positioned near the upper surface of the leaf where light intensity is highest. (Also accept: closely packed to maximise the number of photosynthetic cells in the light path.)
Q2: Describe the process of transpiration. (3 marks)
Answer: Water evaporates from the cell walls of the spongy mesophyll cells inside the leaf. The water vapour diffuses out through the stomata into the surrounding air, down a concentration gradient. This loss of water creates a pull that draws more water up through the xylem from the roots (the transpiration stream).
Q3: Explain how increasing wind speed affects the rate of transpiration. (3 marks)
Answer: Increasing wind speed blows away water vapour from the air just outside the leaf. This maintains a steep concentration gradient of water vapour between the inside of the leaf (high concentration) and the outside air (low concentration after water vapour is blown away). The steeper gradient means water vapour diffuses out of the stomata faster, increasing the transpiration rate.
Q4: Compare xylem and phloem in terms of what they transport, the direction of transport, and whether energy is required. (3 marks)
Answer: Xylem transports water and dissolved minerals; phloem transports dissolved sugars (sucrose). Xylem transports in one direction only (upwards from roots to leaves); phloem transports in both directions (up and down). Xylem transport does not require energy (it is passive, driven by transpiration); phloem transport requires energy from respiration (it is an active process).
Q5: Explain how root hair cells are adapted for absorbing water from the soil. (3 marks)
Answer: Root hair cells have a long, thin projection (the root hair) which greatly increases the surface area for absorption of water from the soil. The thin wall of the root hair creates a short diffusion path, allowing water to enter the cell quickly by osmosis. There are many root hair cells on each root, providing a large total surface area for water uptake.
Q6: A gardener notices that their plants wilt more on hot, windy days than on cool, still days. Explain this observation using your knowledge of transpiration. (4 marks)
Answer: On hot, windy days, the transpiration rate is very high. The high temperature gives water molecules more kinetic energy so they evaporate faster from the mesophyll cells. The wind blows away water vapour from outside the leaf, maintaining a steep concentration gradient so water vapour diffuses out of the stomata faster. The plant loses water faster than it can absorb it from the soil, so the cells lose turgor pressure and the plant wilts. On cool, still days, the transpiration rate is low, so the plant can replace water as fast as it is lost and remains turgid.
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: b7 plant organisation
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)
Extended Answer
Extended question: Extended Answer 6 marks: Explain the adaptations of xylem and phloem and how the transpiration stream works. <div class="
Xylem vessels are made of dead cells forming hollow tubes, strengthened with lignin which makes them waterproof and provides structural support. This allows water and dissolved minerals to flow freely upwards from roots to leaves without obstruction. Phloem is made of living cells — sieve tube elements with perforated sieve plates allow dissolved sugars to flow through, and companion cells provide energy (ATP) for active transport of sugars (translocation). The transpiration stream works because water evaporates from the spongy mesophyll cell surfaces inside the leaf. Water vapour diffuses out through the stomata down a concentration gradient. This loss of water creates a pull that draws more water up through the xylem from the roots, replacing the water lost. This continuous flow is the transpiration stream. Mark scheme: 1 mark for xylem adaptations (dead/hollow/lignin); 1 mark for xylem function; 1 mark for phloem adaptations (living/sieve plates/companion cells); 1 mark for phloem function; 1 mark for transpiration mechanism (evaporation + diffusion); 1 mark for transpiration stream pull
Exam Tips: Learn the difference between transpiration (water loss through stomata) and translocation (sugar transport through phloem) | Xylem = UP only, dead cells, no energy; Phloem = BOTH directions, living cells, energy needed | For transpiration questions, always mention the concentration gradient and diffusion | When explaining factors, say what happens to the concentration gradient (steeper = faster transpiration) | Root hair cells increase surface area - this is the most common answer for this topic | Remember stomata close to reduce water loss, but this also reduces CO₂ entry and therefore photosynthesis | Translocation requires energy from respiration - this is a key difference from xylem tran
Common Errors: Watch Out! 1. Wrong: Plants absorb water through their leaves Correct: Water is absorbed through root hair cells — the leaves are where water exits via transpiration 2. Wrong: Xylem and phloem do the same thing Correct: Xylem transports water and minerals upwards only (passive, dead cells); phloem transports sugars in both directions (active, living cells)
AO3 - Reasoning & Interpretation: Analysis and Evaluation A student measured transpiration rate under different conditions: Condition Rate (arbitrary units) 20 °C, still air, humid 3 20 °C, still air, dry 5 30 °C, still air, dry 9 30 °C, windy, dry 14 30 °C, windy, dry, dark (stomata closed) 2 (a) Explain the increase from 5 to 9 units. (b) Explain why the rate drops to 2 in the final condition despite high temperature and wind. Answers: (a) Increasing temperature from 20 °C to 30 °C gives water molecules more kinetic energy, so they evaporate from mesophyll cells faster, increasing the transpiration rate. (b) In the dark, stomata close to reduce water loss. With stomata closed, water vapour cannot diffuse out of the leaf, s
Stretch & Challenge (Grade 8-9):
- Synoptic links: explain how b7 plant organisation connects to another Combined Science (Trilogy) topic you have studied
- Real-world: research one real-world use or example of b7 plant organisation
- Critical: "What are the limitations of the models used in b7 plant organisation?"
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: Plants are organised (10 mins)
- Exam practice: One past-paper question on b7 plant organisation from the board websites (15 mins)
- Extension: Explain b7 plant organisation to someone else in your own words (10 mins)