• Quick retrieval from earlier learning (Specialised cells). Students answer on mini whiteboards.
• Show answers together and note who needs support in the main task.

1. Which specialised cell has a long thin extension for absorbing water? (nerve cell (neurone) / sperm cell / red blood cell / root hair cell) → root hair cellPrompt: What job would need this feature?
2. What do ciliated cells in the airways do? (absorb food / carry oxygen in the blood / move mucus and trapped dirt away from the lungs / make sperm) → move mucus and trapped dirt away from the lungsPrompt: Cilia are tiny hairs that beat back and forth.
3. Specialised cells: which statement is true? (Root hair cells contain lots of chloroplasts. / All cells in the body look the same. / Sperm cells have no mitochondria. / Stem cells can develop into many different types of cell.) → Stem cells can develop into many different types of cell.Prompt: Match each cell's features to its job.

• Show a microscope image of cells and ask what students think they are looking at.
• Share the objective: Stem cells and their medical uses. Read the success criteria together.

• Work through the example out loud, saying why you do each step, not just what you do.
• Example: Where are stem cells found in a plant?
• Step 1: Meristem tissue can differentiate into any plant cell type throughout the plant's life.
• Step 2: So the answer is: in meristems at the tips of roots and shoots
• Answer: in meristems at the tips of roots and shoots
• Pause after each step and ask a student to say what comes next.

• Do these together. Students try each step on whiteboards before you reveal it.
• Use the hints as prompts rather than giving the answer.

1. What makes a stem cell different from a specialised cell? (It is undifferentiated and can divide to become other cell types / It cannot divide / It can only become a nerve cell / It has no nucleus) → It is undifferentiated and can divide to become other cell typesPrompt: "Differentiation" is when a cell becomes specialised.
2. Stem cells: which statement is true? (Most specialised animal cells can change into any other type of cell. / Adult stem cells are only found in embryos. / Stem cell treatments have no risks. / Plant meristems can be used to produce clones of rare plants quickly.) → Plant meristems can be used to produce clones of rare plants quickly.Prompt: Which type of stem cell is the most flexible?

• 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.

• Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.

1. In therapeutic cloning, an embryo is made with the patient's own genes. What is the main advantage? (The cells never divide / It is free of ethical questions / The stem cells will not be rejected by the patient's immune system / It needs no laboratory) → The stem cells will not be rejected by the patient's immune systemPrompt: Think about why transplanted organs are sometimes rejected.
2. Which type of stem cell: can form almost any type of human cell? (embryonic stem cells / adult stem cells / plant meristem cells) → embryonic stem cellsPrompt: Think about where each type is found.

Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-9.