CGI animation and presenter narration explain the process of diffusion with reference to a plant cell membrane. Diffusion is defined.

First broadcast:
21 November 2008

This clip could be used to prompt questions on the properties and function of the cell membrane. The clip explains that it allows molecules into the cell, but what substances might need to diffuse out? Similarly, it describes how large molecules like starch are too big to enter the cell, this could lead to a study of active transport or endocytosis for higher ability students.