1. Number
Which process increases cell number?
Help beside the question
Read or point first. Choose division or elongation.
Answer guidance
Cell division.
Growth and differentiation: building an organism
Learning objective
Explain how division, elongation and differentiation contribute to growth in plants and animals.
40 minutes · one route · start from what you show today. Point, speak, sign, draw, write or direct an adult. An adult may read or scribe your exact words. Choose one route; do not complete all three.
LAUNCH · GCSE BIOLOGY FOUNDATION · W10 · LESSON 1 · 4 MINUTES
Four clues to start
Supported · 4 questions
2. Size
A root cell becomes longer. What is this called?
Help beside the question
Read or point first. This does not make two cells.
Answer guidance
Elongation.
3. Job
A cell develops a long extension for carrying impulses. What process is occurring?
Help beside the question
Read or point first. It is becoming specialised.
Answer guidance
Differentiation.
4. Compare
Name one process used in both animal and plant growth.
Help beside the question
Read or point first. Use division / elongation / differentiation.
Answer guidance
Cell division or differentiation.
Standard · 4 questions
1. Number
Which process increases cell number?
Help beside the question
Choose division or elongation.
Answer guidance
Cell division.
2. Size
A root cell becomes longer. What is this called?
Help beside the question
This does not make two cells.
Answer guidance
Elongation.
3. Job
A cell develops a long extension for carrying impulses. What process is occurring?
Help beside the question
It is becoming specialised.
Answer guidance
Differentiation.
4. Compare
Name one process used in both animal and plant growth.
Help beside the question
Use division / elongation / differentiation.
Answer guidance
Cell division or differentiation.
Stretch · 4 questions
1. Number
Which process increases cell number?
Help beside the question
Choose division or elongation.
Answer guidance
Cell division.
2. Size
A root cell becomes longer. What is this called?
Help beside the question
This does not make two cells.
Answer guidance
Elongation.
3. Job
A cell develops a long extension for carrying impulses. What process is occurring?
Help beside the question
It is becoming specialised.
Answer guidance
Differentiation.
4. Compare
Name one process used in both animal and plant growth. Give a reason.
Help beside the question
Use division / elongation / differentiation.
Answer guidance
Cell division or differentiation. Accept a scientifically correct reason that uses the relevant model or evidence.
LAUNCH · GCSE BIOLOGY FOUNDATION · W10 · LESSON 1 · 4 MINUTES
Choose a first idea
A root gets longer. Which conclusion is justified?
Think or discuss first. No answer chosen yet.
LAUNCH · GCSE BIOLOGY FOUNDATION · W10 · LESSON 1 · 5 MINUTES
Watch the model
Mitosis increases cell number. New cells can grow before they divide again.
Worked explanation · reveal after thinking
Do not equate growth only with mitosis. Meristems are regions, not the name of every plant stem cell. Differentiation changes cell structure and gene activity; it does not normally remove the other genes.
32-second silent captioned explainer · optional
No sound or autoplay. Use instead of part of the modelling time, not as an extra activity.
Full transcript
More cells. Mitosis increases cell number. New cells can grow before they divide again.
Longer cells. Plant cells can elongate. A longer root is not proof that every cell has divided.
Different jobs. Differentiation produces cells with specialised structures, such as root hair cells or neurones.
Where growth begins. Meristems contain cells that keep dividing. New cells can elongate and differentiate.
LAUNCH · GCSE BIOLOGY FOUNDATION · W10 · LESSON 1 · 5 MINUTES
Sort using the evidence
Choose a card, then choose a group. Explain one placement using its clue.
Drag, or use Tab and Enter to select a card and its group. Pointing or adult-directed placement works too.
Division
Elongation
Differentiation
Choose a card first.
Read the card clues
One cell becomes two: The number of cells increases.
Four similar cells become eight: This is a change in cell number.
A cell length rises from 20 to 30 micrometres: The same cell becomes longer.
A root cell stretches: Cell length increases.
A cell develops a root-hair projection: Structure becomes suited to absorption.
A cell develops a long axon: A neurone is becoming specialised for signalling.
Would a small change help? · optional
Ask the lesson teacher for clearer labels, fewer cards, reading help, an adult-directed model or more thinking time. Your teacher will explain what can change, try it and check its effect. Ask privately or pass; no extra form is needed.
Group explanations · reveal after sorting
One cell becomes two → Division. The number of cells increases.
Four similar cells become eight → Division. This is a change in cell number.
A cell length rises from 20 to 30 micrometres → Elongation. The same cell becomes longer.
A root cell stretches → Elongation. Cell length increases.
A cell develops a root-hair projection → Differentiation. Structure becomes suited to absorption.
A cell develops a long axon → Differentiation. A neurone is becoming specialised for signalling.
LAUNCH · GCSE BIOLOGY FOUNDATION · W10 · LESSON 1 · 4 MINUTES
Work through one example
Worked example
A cell length changes from 15 to 22 micrometres; the number of cells stays at 4. Interpret the change.
Step 1
Select the measurement: cell length, not cell number.
Step 2
Calculate 22 − 15 = 7 micrometres.
Step 3
A longer cell supports elongation.
Step 4
The unchanged count does not provide evidence of division in this observation.
LAUNCH · GCSE BIOLOGY FOUNDATION · W10 · LESSON 1 · 4 MINUTES
Separate the processes
Use the table to identify what was directly measured. Can a larger tissue prove that differentiation occurred?
| Observation | Before | After |
|---|---|---|
| Cell number | 10 | 20 |
| Mean cell length | 20 µm | 30 µm |
| Structure | No projection | Root-hair projection |
Worked explanation · reveal after thinking
Cell number doubling supports division; the 10 µm rise supports elongation; the new specialised projection supports differentiation. Tissue size alone cannot establish differentiation.
LAUNCH · GCSE BIOLOGY FOUNDATION · W10 · LESSON 1 · 10 MINUTES
Show your understanding
Supported · choose one route
1. Identify
Match each row to division, elongation or differentiation.
Use three labels: more cells / longer cells / specialised structure. Match one label to each observation.
2. Calculate
Calculate the increase in mean cell length.
Write the after length ___ and before length ___. Calculate after minus before. Keep the same unit.
3. Explain
Why is “plants grow only by mitosis” incomplete?
Use the frame: plants can grow by division and ___; their cells can also become ___.
Standard · choose one route
1. Identify
Match each row to division, elongation or differentiation.
Look for number, length and structure.
2. Calculate
Calculate the increase in mean cell length.
After minus before; keep the unit.
3. Explain
Why is “plants grow only by mitosis” incomplete?
Add the other processes.
Stretch · choose one route
1. Identify
Match each row to division, elongation or differentiation.
Look for number, length and structure.
2. Calculate
Calculate the increase in mean cell length.
After minus before; keep the unit.
3. Evaluate
Can an increase in tissue mass identify which cells differentiated? Explain.
A total mass measurement has no structural labels.
LAUNCH · GCSE BIOLOGY FOUNDATION · W10 · LESSON 1 · 4 MINUTES
Two small checks
Supported · 2 questions
1. Distinguish
How does division differ from elongation?
Help beside the question
Use: both ___; a difference is ___. Compare cell number and cell length.
Answer guidance
Division increases cell number; elongation increases cell length.
2. Explain
Why is differentiation important in a multicellular organism?
Help beside the question
Use: my answer is ___ because ___. Point to a model or card first. Cells need different structures for different jobs.
Answer guidance
It produces specialised cells with structures suited to particular functions.
Standard · 2 questions
1. Distinguish
How does division differ from elongation?
Help beside the question
Compare cell number and cell length.
Answer guidance
Division increases cell number; elongation increases cell length.
2. Explain
Why is differentiation important in a multicellular organism?
Help beside the question
Cells need different structures for different jobs.
Answer guidance
It produces specialised cells with structures suited to particular functions.
Stretch · 2 questions
1. Distinguish
How does division differ from elongation?
Help beside the question
Compare cell number and cell length.
Answer guidance
Division increases cell number; elongation increases cell length.
2. Evaluate
Can an increase in tissue mass identify which cells differentiated? Explain.
Help beside the question
A total mass measurement has no structural labels.
Answer guidance
No. It measures overall growth, not specialised structures or individual cell fates; further cell observations are needed.
Keep one useful science explanation. No additional participation record is required.