Diffusion - Transport in Cells

Importance of Transport in Cells

• Organisms require movement of substances in and out of cells for survival.
• Three main processes involved in this movement:
  • Diffusion
  • Osmosis
  • Active Transport

Diffusion

• Definition: Movement of molecules from an area of higher concentration to an area of lower concentration.
• Particles in liquids and gases move continuously and spread evenly over time.
  • Net movement from high to low concentration.
  • Particles continue moving even after evenly spread.

Biological Examples of Diffusion

• In a Leaf:

  • Diffusion allows gases involved in photosynthesis to move in and out of leaf cells.

• In the Lungs:

  • Oxygen: High concentration in alveolus diffuses into blood.
  • Carbon Dioxide: High concentration in blood diffuses into alveolus.

• In Liver Cells:

  • Various substances diffuse to assist in metabolism and detoxification.

Additional Learning Resources

• Cell Structure
• Cell Division

Related Topics

• Comparing Diffusion, Osmosis, and Active Transport
• Simple Compound Measures of Rate
• Analysing Results

Explore More

• How to Investigate Osmosis
• Active Transport

Additional Resources and Links

• Biology Revision Resources: BBC Bitesize
• Interactive Activities: Mitosis - AQA

Further reading and interactive activities can deepen understanding of diffusion and its role in biological processes.

These notes aim to provide a concise summary of key concepts related to diffusion in biological systems as outlined by the BBC Bitesize guide.