--- title: "What makes a plant cell different?" subtitle: "Year 8 Biology · Cells · Lesson 4" --- # What makes a plant cell different? **Name:** {{field-24}} **Date:** {{field-15}} **Class:** {{field-15}} > **Key question:** A tree can stand 80 metres tall without a single bone. A lettuce leaf goes limp in the fridge, then crisp again in cold water. Both come down to parts that only plant cells have. :::teacher-note **In one sentence:** Students identify the cell wall, chloroplasts and large vacuole as plant-only structures and explain each, describe mitochondria and ribosomes in both cell types, and link a cell's organelles to its job (AC9S8U01, nodes 4 and 5). **Students should be able to say:** I can name the parts only plant cells have and say what each is for. I can say which parts plant and animal cells share. I can explain why some cells have more of one part than others. **Width:** the unmarked parts are the floor every student does (Engage, Explore, Explain, Evaluate). Typical and Wider sections add contexts, not difficulty. Students work in the online tutorial alongside this sheet. ::: ## Engage :::keep-together **Which of these does a plant leaf cell have that a cheek cell does not?** ☐ A nucleus ☐ A cell wall, chloroplasts and a large vacuole ☐ A cell membrane ☐ Mitochondria My prediction, and why: {{lines-3}} ::: :::teacher-note **What happens:** A cell wall, chloroplasts and a large vacuole. Both cells have mitochondria, a nucleus and a membrane: plants release energy from food just as animals do. ::: ## Explore Try it on the board in the tutorial. Was your prediction right? What was different? {{lines-2}} ## Explain: what each part is for :::keep-together ### Jobs **Match each part to its job.** A. Holds cell sap and keeps the cell firm B. Photosynthesis: captures light to make glucose C. Make proteins D. Release energy from food (respiration) E. Rigid support, so the plant holds its shape without a skeleton {{columns 60% 40%}} {{rows 1}} | Part | Letter | |---|---| | `Cell wall` | | | `Chloroplast` | | | `Large vacuole` | | | `Mitochondria` | | | `Ribosomes` | | ::: :::teacher-note **Answer:** Cell wall → E. Rigid support, so the plant holds its shape without a skeleton; Chloroplast → B. Photosynthesis: captures light to make glucose; Large vacuole → A. Holds cell sap and keeps the cell firm; Mitochondria → D. Release energy from food (respiration); Ribosomes → C. Make proteins The first three are only in plant cells (walls also in fungi and bacteria). Mitochondria and ribosomes are in both. ::: :::keep-together ### Plant only or both **Plant cells only, or both plant and animal cells?** Groups: Plant only, Both - Cell wall: {{field-15}} - Chloroplasts: {{field-15}} - Large permanent vacuole: {{field-15}} - Mitochondria: {{field-15}} - Ribosomes: {{field-15}} - Nucleus: {{field-15}} ::: :::teacher-note **Answer:** Cell wall → Plant only; Chloroplasts → Plant only; Large permanent vacuole → Plant only; Mitochondria → Both; Ribosomes → Both; Nucleus → Both ::: :::keep-together ### No chloroplasts **Why don't animal cells need chloroplasts?** ☐ Animals get their food by eating, so they don't make it from light ☐ Animal cells are too small for chloroplasts ☐ Animals live where there is no light ::: :::teacher-note **Answer:** Animals get their food by eating, so they don't make it from light Plants make their own food by photosynthesis; animals eat. Each cell's parts match how the organism lives. ::: :::keep-together ### A limp lettuce **A lettuce leaf goes limp when it loses water. Which part explains this?** ☐ The vacuoles shrink, so the cells push less against their walls ☐ The cell walls dissolve ☐ The chloroplasts stop working ::: :::teacher-note **Answer:** The vacuoles shrink, so the cells push less against their walls A full vacuole presses the cell against its wall and keeps it firm. Lose water and the cell goes soft: the leaf wilts. Put it in water and it firms up again. ::: :::keep-together ### Many mitochondria **A muscle cell has far more mitochondria than a skin cell. Why?** ☐ Mitochondria make muscles strong ☐ Muscle cells are bigger ☐ Contracting needs a lot of energy, and mitochondria release it ::: :::teacher-note **Answer:** Contracting needs a lot of energy, and mitochondria release it Cells have the parts their job needs, in the numbers it needs: same DNA, different organelles. ::: :::typical ## Elaborate: a root hair cell :::keep-together ### No chloroplasts **Root hair cells have no chloroplasts. Why not?** ☐ They are not plant cells ☐ Chloroplasts would make them too heavy ☐ They are underground, with no light to photosynthesise; their job is taking in water ::: :::teacher-note **Answer:** They are underground, with no light to photosynthesise; their job is taking in water A cell has the parts its job needs. Chloroplasts in the dark would be useless. ::: ::: :::wider ## Elaborate: energy for movement :::keep-together ### Protein factories **Cells in a gland that makes digestive enzymes (proteins) are packed with one organelle. Which?** ☐ Ribosomes, which make proteins ☐ Chloroplasts ☐ Vacuoles ::: :::teacher-note **Answer:** Ribosomes, which make proteins Enzymes are proteins, and ribosomes make proteins. Like mitochondria in muscle, the number of an organelle follows the job. ::: ::: ## Evaluate: look back Write one sentence: "At first I thought… Now I think… because…" **Revision summary** - Only plant cells have a **cell wall** (support), **chloroplasts** (photosynthesis) and a **large vacuole** (keeps the cell firm, stores sap). - Plant and animal cells both have a nucleus, membrane, cytoplasm, **mitochondria** (release energy from food) and **ribosomes** (make proteins). - How many of each part a cell has depends on its job: muscle cells have many mitochondria; root hair cells have no chloroplasts. ## Exit ticket :::keep-together **Name two parts a leaf cell has that a cheek cell lacks, and say what each does.** {{lines-3}} ::: :::teacher-note **Answer:** Any two of: cell wall (support), chloroplasts (photosynthesis), large vacuole (keeps the cell firm, stores sap). :::