The Invisible Living World: Beyond Our Naked Eye
What each part of a cell does
Learn what each part of a cell does.
Each part of a cell has its own job.
| Part | Its job |
|---|---|
| cell membrane | wraps the cytoplasm and nucleus and keeps one cell apart from the next; it is porous, so it lets in what the cell needs and lets out its waste, like a guard keeping a register at the gate |
| cytoplasm | holds the cell's other parts and substances such as carbohydrates, proteins, fats and mineral salts; most life processes happen here |
| nucleus | the control centre: it regulates everything the cell does, and its growth |
| cell wall (plants) | gives the plant rigidity and strength, so plant cells sit tightly together and look firm |
Why do plants need a wall? In a storm you can run for shelter. A plant cannot run anywhere, so its cells carry their own strong wall.
Plant cells have more besides. All parts of a plant have tiny rod-shaped plastids. Some, the chloroplasts, contain green chlorophyll and help in photosynthesis. In parts that are not green, plastids store substances.
Plant cells also have a large, empty-looking space, the vacuole. It stores useful substances, helps get rid of waste and keeps the cell's shape, which gives the plant strength and support. Animal cells usually have no vacuole, and if they have one it is small, storing substances dissolved in water.
So a cell is not just a bag of liquid. It is made of many parts, each with its own job, and together they keep the cell, and the whole living thing, working.
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