Science lesson plan · 9th grade (Year 10 in England) · 45 minutes
Mitosis and meiosis
Cells, genetics and evolution
CCSS NGSS.HS-LS1-4CCSS NGSS.MS-LS3-2England: KS4 Combined Science: Cell biologyEngland: KS4 Combined Science: Evolution, inheritance and variation
Objective and success criteria
Students will: Mitosis and meiosis.
- I can answer questions on today's skill on my own, without help.
- I can explain each step and say why it works.
- I can check my answer and spot a mistake.
Before and after
Needs first: DNA, genes and chromosomes
Leads to: The cell cycle and the stages of mitosis; Count chromosomes after mitosis, meiosis and fertilisation
Materials: Microscope images or slides, Cell diagrams, Mini whiteboards, A diagram or short video clip of the idea, Printed student sheet (below).
Warm-up · 5 min
- Quick retrieval from earlier learning (DNA, genes and chromosomes). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Where is DNA found in an animal cell? (in the chloroplasts / outside the cell / mainly in the nucleus / in the cell wall) → mainly in the nucleusPrompt: It is the control centre of the cell.
- Human body cells have 23 pairs of chromosomes. How many chromosomes are in a sperm cell? → 23Prompt: Is this a gamete (sex cell) or a body cell?
- What shape is a DNA molecule? (a single straight line / a cube / a double helix / a ring of six atoms) → a double helixPrompt: It looks like a twisted ladder.
Hook · 5 min
- Show a microscope image of cells and ask what students think they are looking at.
- Share the objective: Mitosis and meiosis. Read the success criteria together.
I do: model it · 10 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: Mitosis or meiosis? It produces genetically different cells.
- Step 1: Meiosis makes four genetically different gametes with half the chromosomes.
- Step 2: So the answer is: meiosis
- Answer: meiosis
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 10 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- Mitosis or meiosis? It halves the chromosome number (23 in humans). (mitosis / meiosis) → meiosisPrompt: Which one makes sex cells (gametes)?
- A bacterium divides into two every 30 minutes. Starting with one cell, how many cells are there after 1.5 hours (if none die)? → 8Prompt: How many divisions happen in that time?
You do: independent practice · 10 min
- Students work on the student sheet. Circulate and check the first two answers of every student early.
- Students who finish: write a question of their own for a partner, with the answer.
The 8 questions are on the student sheet below, with answers in the key.
Exit ticket · 5 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- Mitosis or meiosis? It makes two identical cells. (mitosis / meiosis) → mitosisPrompt: Which one makes sex cells (gametes)?
- Before a cell divides by mitosis, what must it do? (stop respiring / halve its chromosomes / copy its DNA / lose its nucleus) → copy its DNAPrompt: Each new cell needs a full set of chromosomes.
Watch out for
- Everyday meanings of words getting in the way of the science meaning: define key words explicitly.
- Remembering facts without the reason: ask "why?" and "what is the evidence?"
Support and stretch
Support
- Review first: DNA, genes and chromosomes.
- Use concrete materials: microscope images or slides.
- Give the first step of each question, or a partly worked example to finish.
- Pair with a confident partner for the guided practice.
Stretch
- Move on to: The cell cycle and the stages of mitosis; Count chromosomes after mitosis, meiosis and fertilisation.
- Explain a common mistake in writing and how to fix it.
- Write a word problem that uses today's skill, then solve a partner's.
Homework and more practice
Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-9.
Free lesson plan from eurekami.com/lesson-plan-builder