What it shows
A plant cell has a rigid cell wall, a cell membrane, a nucleus, a large vacuole and green chloroplasts. The model shows where each part sits and what job it does.
The science
The cell wall is a stiff box made of cellulose that gives a plant cell its fixed shape. Inside it, the thin cell membrane controls what enters and leaves. The nucleus holds the instructions for the cell, the chloroplasts make food by photosynthesis, and the big vacuole stores water and keeps the cell firm. Animal cells lack a wall, chloroplasts and a large vacuole.
Materials
Cost: under Rs 50. Many items come from home or from waste; spare parts such as LEDs, motors and wire are in the store.
- A rectangular foil or thermocol tray (free from sweet shops)
- Green, brown and orange clay or atta dough
- A ping-pong ball or a ball of clay for the nucleus
- A transparent plastic pouch filled with green gel or water for the vacuole
- Toothpicks and paper flags for labels
- Glue and a few dry beans as ribosomes
Safety
For this project: An adult must cut the thermocol or plastic with a knife. Keep beans and small parts away from young children.
Never use mains electricity: power models with cells, batteries or a low-voltage adapter. Sharp and hot tools, flames and lab chemicals need an adult or your teacher beside you. Keep magnets, button cells and small parts away from young children, and wash your hands after making.
All the safety rulesStep by step
8 steps. Do them in order, and test each part before you go on to the next. Write what you notice in a notebook as you go.
Take the tray as the cell wall and colour the outer rim dark green with paint or marker.
Line the inside with a thin layer of clear plastic or a thin film of glue to show the cell membrane.
Press a large pouch of green gel into one side of the tray as the central vacuole.
Place the ball in the middle of the free space as the nucleus and add a small clay dot inside it as the nucleolus.
Roll ten small oval pieces of green clay for chloroplasts and press them near the wall.
Add sausage shapes of orange clay as mitochondria and stick dry beans around as ribosomes.
Fix a toothpick flag to every part and write its name and job on a small label.
Make a second small tray without wall, chloroplasts and vacuole to compare with an animal cell.
What you should see
A clearly labelled plant cell tray beside an animal cell tray, with at least eight parts named and the three differences easy to point out.
Viva questions
A teacher or a judge will ask how it works. Try to answer each question before you open it, then compare.
1Which part gives a plant cell its fixed shape?
The cell wall made of cellulose.
2Where is food made in a plant cell?
In the chloroplasts, which contain chlorophyll.
3What does the vacuole do?
It stores water and sap and keeps the cell firm.
4Name one part that an animal cell lacks.
The cell wall, the chloroplasts or the large central vacuole.
Take it further
Look at an onion peel under a magnifier or microscope and match what you see to your model.
Change one thing, measure what happens, and add a table or chart of your readings: that is what turns a model into your own investigation.
Free ebooks for this project
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