- Science
- Ages 8–14
- 11 min
- intermediate
The Plant Cell
Inside every leaf are millions of tiny building blocks, each with its own walls, storage tanks and food factories.
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What is The Plant Cell?
Every part of a plant — root, stem, leaf and flower — is built from cells, each far too small to see without a microscope. A plant cell is a tiny, self-contained unit with a strong outer wall, a control centre, food-making factories and a large water store.
Understanding what is inside a plant cell explains a great deal about plants themselves: why wood is stiff, why leaves are green, and why a thirsty plant droops.
What you will learn
- Explain that plants are built from many tiny cells
- Name three parts of a plant cell and what each does
- Say what makes a plant cell different from an animal cell
The main parts
The cell wall is a rigid outer layer made of cellulose. It gives the cell its shape and stops it bursting when it fills with water.
The cell membrane sits just inside the wall and controls what enters and leaves. The nucleus is the control centre, holding the cell's DNA. The cytoplasm is the jelly-like fluid where much of the cell's chemistry happens.
Chloroplasts are the green structures where photosynthesis takes place, and the vacuole is a large sac of fluid that stores water and keeps the cell firm.
How plant cells differ from animal cells
Three structures are found in plant cells and not in animal cells: the cell wall, chloroplasts and a large permanent vacuole.
Those three differences explain a lot. The cell wall is why plants can stand up without a skeleton. Chloroplasts are why plants make their own food instead of eating. And the vacuole is why a well-watered plant is firm and a dry one wilts.
Why plants wilt
When a plant cell is full of water, the vacuole presses outward against the cell wall and the cell becomes turgid — firm and rigid. Millions of turgid cells together hold a stem upright.
When water is short, the vacuoles shrink, the pressure drops, and the cells go floppy. The whole plant droops. Water it, the vacuoles refill, and within hours the plant stands up again.
Step by step
- Roots supply water to the plant
- Water enters plant cells and fills the vacuole
- The vacuole presses the membrane outward
- The strong cell wall resists the pressure
- The cells become turgid and help the plant stand upright
Key words
- Cell wall
- A strong outer layer around a plant cell. It holds the cell in shape, like a cardboard box around something soft.
- Chloroplast
- The tiny green parts inside the cell where the plant makes its food. They are what make leaves green.
- Vacuole
- A big bag of water in the middle of the cell. When it is full the plant stands up straight; when it empties, the plant wilts.
Common questions
What are the main parts of a plant cell?
The cell wall, cell membrane, nucleus, cytoplasm, chloroplasts, mitochondria and a large permanent vacuole. Each has a specific job, from controlling the cell to making food and storing water.
What is the difference between a plant cell and an animal cell?
Plant cells have three structures animal cells lack: a rigid cell wall, chloroplasts for photosynthesis, and a large permanent vacuole. This is why plants can stand upright and make their own food.
What does the cell wall do?
The cell wall is a rigid layer of cellulose around the outside of a plant cell. It gives the cell its shape, supports the plant, and stops the cell from bursting when it absorbs water.
Why do plants wilt when they are not watered?
Each plant cell contains a vacuole that fills with water and presses against the cell wall, keeping the cell firm. Without enough water the vacuoles shrink, the cells go floppy, and the plant droops until it is watered again.
Ready to explore it?
The interactive lesson walks through The Plant Cell step by step, with animations you control.
Start Interactive LessonRelated topics
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Photosynthesis
How green plants use sunlight, water and air to make their own food — and give us the oxygen we breathe.
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