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Home > Biology > Investigating cells > Cells and diffusion


Cells and diffusion

Cell structure

All living tissue is made of microscopic units called cells [cell: Basic unit of life. Unicellular organisms only have one cell. Multicellular organisms have many cells.. We can see more structures clearly if we use stains to colour specimens before putting them under the microscope. Stains are coloured dyes which are absorbed by some cell structures but not by others.

In addition to these structures plant cells also have a cell wall made of cellulose [cellulose: A carbohydrate. It forms the cell wall in plant cells. which provides a tough but permeable outer casing for the cell, and may also have chloroplasts [chloroplasts: Microscopic structures containing chlorophyl found in green plant cells where photosynthesis takes place. which carry out photosynthesis and a sap vacuole which is a reservoir of water and solutes.

The image below shows plant cells as seen under the microscope. The chloroplasts can be seen as round green structures within the cells.

Round green chlorplasts in plant cells see under the microscope


Listen to the Naked Scientists explanation of the structure of cells.

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Magnified cells

Class Clips

Video clip exploring plant and animal cells


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Tombstone Timeout

Test out your knowledge of biology with Mia Cadaver's biology game - it's serious fun!

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