Additional Science - Biology - Unit 2 - Diffusion

Everything you need to know about Diffusion.

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  • Created by: Emma
  • Created on: 23-04-11 20:26

What is Diffusion?


Dissolved substances have to pass through the cell membrane to get into or out of a cell.

Diffusion is one of the processes that allows this to happen.

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How does Diffusion occur?

Diffusion occurs when particles spread.

They move from a region where they are in high concentration to a region where they are in low concentration.

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When does Diffusion happen?


Diffusion happens when the particles are free to move.

This is true in gases and for particles dissolved in solutions.

Particles diffuse down a concentration gradient, from an area of high concentration to an area of low concentration.

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Examples of Diffusion


In the gut, digested food products move from the gut cavity to the blood in the capillary of villus. This moves all of the important nutrients and minerals from the food you eat into the cells lining the intestine and into the bloodstream.

In the lungs, oxygen particles move from the alveolar air space to the  blood circulation around the lungs. Oxygen diffuses across the alveolar walls into the blood, and the circulation takes the oxygen-rich blood away.

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Always remember..

Particles will continue to move from a high to a low concentration while the concentration is different between two areas.

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thank you :D This helped with my homework so much!

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