Study Guides

Unit Summary

This unit explores diffusion's role in material movement in and between cells and involves making predictions, observations and measurements with various methods.

Lesson Summary

You will learn to explain that diffusion is the movement of particles of a substance from an area of higher to lower concentration.

Key Notes

• All substances, including the cell cytoplasm and substances within it, are made up of particles.
• These particles move in random directions and collide all the time.
• Concentration is the number of particles in a volume of liquid or gas.
• The net movement of particles is down a concentration gradient.
• Diffusion is the passive movement of particles of a substance from an area of higher to lower concentration.

Vocabulary To Learn

• passive process: A passive process doesn't require any additional energy.
• concentration: Concentration is the number of particles in a volume of liquid or gas.
• concentration gradient: A concentration gradient is a difference in the concentration of particles from one area to another.
• net movement: Net movement is the overall movement of particles from one area to another.
• diffusion: Diffusion is the net movement of a substance from an area of higher concentration to an area of lower concentration.

Common Mistakes To Avoid

• Particles want or intend to spread out; particles stop moving after equilibrium has been reached.

3 Quick Questions (With Answers)

More Lessons In This Unit

• Diffusion through a permeable material: practical Study Guide
• Diffusion through a selectively-permeable membrane: practical Study Guide
• Diffusion through the cell membrane Study Guide