• 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 no chloroplasts because it is underground? (sperm cell / palisade cell / root hair cell / red blood cell) → root hair cellPrompt: What job would need this feature?
2. What does it mean when a cell differentiates? (It becomes specialised for a particular job. / It loses all its DNA. / It dies. / It divides into four cells.) → It becomes specialised for a particular job.Prompt: Stem cells can do this.
3. Specialised cells: which statement is true? (Sperm cells have no mitochondria. / Root hair cells contain lots of chloroplasts. / All cells in the body look the same. / Red blood cells have no nucleus.) → Red blood cells have no nucleus.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 cannot divide / It is undifferentiated and can divide to become other cell types / It has no nucleus / It can only become a nerve cell) → 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? (Embryonic stem cells can differentiate into almost any type of human cell. / Most specialised animal cells can change into any other type of cell. / Stem cell treatments have no risks. / Adult stem cells are only found in embryos.) → Embryonic stem cells can differentiate into almost any type of human cell.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. Bone marrow transplants help some people with leukaemia (leukemia). Why? (The marrow becomes a new heart / Bone marrow contains antibiotics / Marrow cells kill all viruses / Adult stem cells in the marrow can make new healthy blood cells) → Adult stem cells in the marrow can make new healthy blood cellsPrompt: What does bone marrow normally make?
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.