1. Copy
What is copied before mitosis?
Help beside the question
Read or point first. Name the information molecule.
Answer guidance
DNA.
Identical daughter cells: explain the outcome
Learning objective
Explain how copying and separation conserve genetic information in growth, repair and asexual reproduction.
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 · W9 · LESSON 3 · 4 MINUTES
Four clues to start
Supported · 4 questions
2. Separate
How many sets must be shared between the two new nuclei?
Help beside the question
Read or point first. There must be a full set at each end.
Answer guidance
Two identical complete sets, one for each daughter nucleus.
3. Use
Which process replaces cells lost from skin?
Help beside the question
Read or point first. Think growth, repair or fertilisation.
Answer guidance
Mitosis for repair/replacement.
4. Human count
A typical human body cell has 46 chromosomes. How many does each daughter cell have after mitosis?
Help beside the question
Read or point first. The number is conserved.
Answer guidance
46.
Standard · 4 questions
1. Copy
What is copied before mitosis?
Help beside the question
Name the information molecule.
Answer guidance
DNA.
2. Separate
How many sets must be shared between the two new nuclei?
Help beside the question
There must be a full set at each end.
Answer guidance
Two identical complete sets, one for each daughter nucleus.
3. Use
Which process replaces cells lost from skin?
Help beside the question
Think growth, repair or fertilisation.
Answer guidance
Mitosis for repair/replacement.
4. Human count
A typical human body cell has 46 chromosomes. How many does each daughter cell have after mitosis?
Help beside the question
The number is conserved.
Answer guidance
46.
Stretch · 4 questions
1. Copy
What is copied before mitosis?
Help beside the question
Name the information molecule.
Answer guidance
DNA.
2. Separate
How many sets must be shared between the two new nuclei?
Help beside the question
There must be a full set at each end.
Answer guidance
Two identical complete sets, one for each daughter nucleus.
3. Use
Which process replaces cells lost from skin?
Help beside the question
Think growth, repair or fertilisation.
Answer guidance
Mitosis for repair/replacement.
4. Human count
A typical human body cell has 46 chromosomes. How many does each daughter cell have after mitosis? Give a reason.
Help beside the question
The number is conserved.
Answer guidance
46. Accept a scientifically correct reason that uses the relevant model or evidence.
LAUNCH · GCSE BIOLOGY FOUNDATION · W9 · LESSON 3 · 4 MINUTES
Choose a first idea
Which claim best describes normal mitosis?
Think or discuss first. No answer chosen yet.
LAUNCH · GCSE BIOLOGY FOUNDATION · W9 · LESSON 3 · 5 MINUTES
Watch the model
During interphase the cell grows and copies its DNA. Each replicated chromosome has two joined sister chromatids.
Worked explanation · reveal after thinking
This schematic uses four chromosomes, not the human number. A replicated X is one chromosome with two sister chromatids. After chromatids separate, each is a chromosome. DNA copying does not mean each daughter cell has twice the chromosome number. The full cycle includes interphase, mitosis and cytokinesis. Interphase chromosome symbols show DNA copies schematically; the chromosomes are not normally visibly condensed at this stage.
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
Prepare and copy. During interphase the cell grows and copies its DNA. Each replicated chromosome has two joined sister chromatids.
Line up. During metaphase the replicated chromosomes line up at the centre of the cell.
Separate copies. During anaphase sister chromatids separate. One copy of each chromosome moves to each end.
Divide the cell. Nuclei reform and the cytoplasm divides. Two daughter cells each receive the same chromosome set.
LAUNCH · GCSE BIOLOGY FOUNDATION · W9 · LESSON 3 · 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.
Fits normal mitosis
Does not fit normal mitosis
Choose a card first.
Read the card clues
One cell becomes two: Cytokinesis forms separate daughter cells.
Each daughter keeps the full chromosome set: Each receives a copy of each chromosome.
Repair replaces lost cells: Mitosis provides replacement cells.
Each daughter has half the chromosome number: That is not the normal outcome of mitosis.
Every division doubles chromosomes in each daughter: Chromosome number is conserved in each daughter.
Asexual offspring can be genetically identical: Mitosis can support asexual reproduction without combining gametes.
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 → Fits normal mitosis. Cytokinesis forms separate daughter cells.
Each daughter keeps the full chromosome set → Fits normal mitosis. Each receives a copy of each chromosome.
Repair replaces lost cells → Fits normal mitosis. Mitosis provides replacement cells.
Each daughter has half the chromosome number → Does not fit normal mitosis. That is not the normal outcome of mitosis.
Every division doubles chromosomes in each daughter → Does not fit normal mitosis. Chromosome number is conserved in each daughter.
Asexual offspring can be genetically identical → Fits normal mitosis. Mitosis can support asexual reproduction without combining gametes.
LAUNCH · GCSE BIOLOGY FOUNDATION · W9 · LESSON 3 · 4 MINUTES
Work through one example
Worked example
A parent model has 10 chromosomes. Predict the chromosome number in each daughter.
Step 1
The parent starts with a full set of 10.
Step 2
DNA is copied before mitosis.
Step 3
The copies separate into two full sets.
Step 4
Each daughter has 10 chromosomes, not 5 or 20.
LAUNCH · GCSE BIOLOGY FOUNDATION · W9 · LESSON 3 · 4 MINUTES
Audit three cell models
Parent cells each have 6 chromosomes. Decide which daughter-cell model fits normal mitosis; explain why the other models fail.
| Model | Daughter 1 | Daughter 2 |
|---|---|---|
| A | 6 chromosomes | 6 chromosomes |
| B | 3 chromosomes | 3 chromosomes |
| C | 8 chromosomes | 4 chromosomes |
Worked explanation · reveal after thinking
A fits: both retain the full set of six. B halves the number; C distributes the copies unequally. A chromosome count alone cannot prove the DNA sequence is identical, but it fits the intended model.
LAUNCH · GCSE BIOLOGY FOUNDATION · W9 · LESSON 3 · 10 MINUTES
Show your understanding
Supported · choose one route
1. Choose
Select A, B or C and justify the choice.
For each model, compare parent count → daughter 1 count → daughter 2 count. Circle the matching counts.
2. Explain
Explain why a daughter cell does not normally receive 12 chromosomes in this model.
Complete: each daughter receives one ___ set, not both sets. Show this using the chromosome tokens.
3. Apply
Give one growth example and one repair example.
Choose from new growth / replacing lost cells. Give one example for each job.
Standard · choose one route
1. Choose
Select A, B or C and justify the choice.
Use a chromosome count in your explanation.
2. Explain
Explain why a daughter cell does not normally receive 12 chromosomes in this model.
Do not confuse DNA copying with the final count.
3. Apply
Give one growth example and one repair example.
New cells may increase tissue size or replace lost cells.
Stretch · choose one route
1. Choose
Select A, B or C and justify the choice.
Use a chromosome count in your explanation.
2. Explain
Explain why a daughter cell does not normally receive 12 chromosomes in this model.
Do not confuse DNA copying with the final count.
3. Calculate and qualify
Starting with 3 cells, predict the number after 3 rounds of division. State one assumption.
Each living cell divides into two in every round.
LAUNCH · GCSE BIOLOGY FOUNDATION · W9 · LESSON 3 · 4 MINUTES
Two small checks
Supported · 2 questions
1. Mechanism
Give two linked steps that explain identical daughter nuclei.
Help beside the question
Use: my answer is ___ because ___. Point to a model or card first. Copy accurately; share one copy of each.
Answer guidance
DNA is copied before mitosis, then chromosome copies separate so each new nucleus receives the same set.
2. Application
Why is mitosis suitable for repairing tissue?
Help beside the question
Use: my answer is ___ because ___. Point to a model or card first. Connect replacement with the same genetic information.
Answer guidance
It produces more cells with the same genetic information for replacing damaged or lost cells.
Standard · 2 questions
1. Mechanism
Give two linked steps that explain identical daughter nuclei.
Help beside the question
Copy accurately; share one copy of each.
Answer guidance
DNA is copied before mitosis, then chromosome copies separate so each new nucleus receives the same set.
2. Application
Why is mitosis suitable for repairing tissue?
Help beside the question
Connect replacement with the same genetic information.
Answer guidance
It produces more cells with the same genetic information for replacing damaged or lost cells.
Stretch · 2 questions
1. Mechanism
Give two linked steps that explain identical daughter nuclei.
Help beside the question
Copy accurately; share one copy of each.
Answer guidance
DNA is copied before mitosis, then chromosome copies separate so each new nucleus receives the same set.
2. Calculate and qualify
Starting with 3 cells, predict the number after 3 rounds of division. State one assumption.
Help beside the question
Each living cell divides into two in every round.
Answer guidance
3 × 2 × 2 × 2 = 24; assumes every cell divides once per round and no cells die.
Keep one useful science explanation. No additional participation record is required.