The basic building block of animals and plants is the cell. Cells are very small and we need a microscope to see them. The photographs show animal cells and plant cells, as seen through a microscope.
These are cheek cells, seen through a microscope
These are onion cells, seen through a microscope
Cells are made up of different parts. It is easier to explain what these parts are by using diagrams like the ones below.
Animal cells usually have an irregular shape, and plant cells usually have a regular shape
Animal cells and plant cells both contain:
- cell membrane
- cytoplasm
- nucleus
Plant cells only also contain:
- chloroplasts
- vacuole
- cell wall
The table summarises the functions or jobs of these parts.
| Part |
Function |
| Cell membrane |
Controls what substances can get into and out of the cell. |
| Cytoplasm |
Jelly-like substance, where chemical reactions happen. In plant cells there's a thin lining, whereas in animal cells most of the cell is cytoplasm. |
| Nucleus |
Controls what happens inside the cell - it is not a 'brain'. |
| Chloroplast |
Where photosynthesis happens – chloroplasts contain a green substance called chlorophyll. |
| Vacuole |
Contains a liquid called cell sap, which keeps the cell firm. |
| Cell wall |
Made of a tough substance called cellulose, which supports the cell. |
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