Bitesize has changed! We're updating subjects as fast as we can. Visit our new site to find Bitesize guides and clips - and tell us what you think!

Did you know?

We also have Bitesize study guides covering many subjects at National 4 and National 5 on our Knowledge & Learning BETA website.

Home > Biology > Investigating cells > Cells and diffusion

Biology

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.

In order to see this content you need to have both Javascript enabled and Flash installed.

 

Watch

Magnified cells

Class Clips

Video clip exploring plant and animal cells

Play

A picture of Mia Cadaver

Tombstone Timeout

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

BBC © 2014 The BBC is not responsible for the content of external sites. Read more.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.