Science Class 9
Cell: The Building Block of Life
How cells build living things, their parts, membrane, kinds, and how they divide.
13 lessons · ~70 min total
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Lessons in this topic
- 0 Start here What a cell is, its parts, and how one becomes two, in one picture. · 3 min You are here
- 1 Everything is made of them Living things are one cell or many. Count cells to find a size. · 6 min
- 2 Inside one cell A cell holds working parts called organelles. Each has its own job. · 6 min
- 3 The boundary decides The cell membrane lets some things pass. Water crosses toward more solute. · 6 min
- 4 A plant cell and an animal cell A plant cell has a wall, chloroplasts and a big vacuole. An animal cell has none. · 6 min
- 5 Three kinds of plastid Plastids are plant organelles. Each kind has its own pigment and job. · 5 min
- 6 Checkpoint: parts, water and plant cells A graded check on the first five lessons. · 5 min
- 7 Two kinds of cell Some cells keep DNA in a nucleus. Others keep it loose. · 6 min
- 8 How big a cell can get A cell takes in materials across its surface. A bigger cell has less surface per part. · 6 min
- 9 One becomes two Mitosis makes two identical cells. Meiosis makes four cells with half the chromosomes. · 6 min
- 10 When cells divide without control Normal cells divide in a controlled way. Cancer cells lose that control. · 5 min
- 11 The big picture The whole chapter on one screen. · 3 min
- 12 Track quiz Nine quick questions, one for each idea. · 7 min
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