Year 10 - Science
Moving into and out of the blood: diffusion, osmosis and active transport
Transport and exchange surfaces in humans
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
This unit covers the human circulatory system, its link to the gas exchange system, and the adaptations of the heart, blood vessels, and blood components. It explains transport mechanisms like diffusion, osmosis, and active transport, and the need for exchange surfaces in multicellular organisms.
Lesson Summary
You will learn to explain how particles of substances move into and out of the blood by diffusion, osmosis and active transport.
Key Notes
- Particles of substances move into and out of the blood through selectively-permeable cell membranes.
- Oxygen, carbon dioxide and other small particles move into and out of the blood by diffusion.
- Water moves into and out of the blood by osmosis, a type of diffusion.
- The net movement of particles by diffusion and osmosis is down a concentration gradient.
- Large particles are moved into and out of the blood by active transport, which requires energy.
Vocabulary To Learn
- selectively-permeable membrane: A membrane that will only allow some substances through and not others.
- diffusion: Diffusion is the net movement of particles from an area of higher concentration to an area of lower concentration.
- net movement: The overall movement of particles.
- osmosis: The net movement of water molecules from high to low concentration through a selectively-permeable membrane.
- active transport: The net movement of particles against a concentration gradient using energy.
Common Mistakes To Avoid
- Mistakes with the definitions of diffusion, osmosis and active transport are common, as are their application to biological scenarios.
3 Quick Questions (With Answers)
1. Explain the scientific idea in this lesson using two key points.
Particles of substances move into and out of the blood through selectively-permeable cell membranes. Oxygen, carbon dioxide and other small particles move into and out of the blood by diffusion.
2. Define this scientific word and use it in context. 'selectively-permeable membrane'
A membrane that will only allow some substances through and not others. Include the word in a full scientific explanation, not as a single label.
3. Correct this common scientific misunderstanding.
Mistake: Mistakes with the definitions of diffusion, osmosis and active transport are common, as are their application to biological scenarios. Correction: The definitions are clearly stated and contextualised using key human biological processes and examples.
More Lessons In This Unit
- Diffusion and surface area to volume ratio Study Guide
- Diffusion and surface area to volume ratio, including Fick's law Study Guide
- Human blood cells and blood vessels Study Guide
- Microscopy of human blood cells and blood vessels Study Guide
- The human circulatory system Study Guide
- The human heart and double circulatory system Study Guide
- The human heart and double circulatory system, including calculating cardiac output Study Guide
- The importance of exchange surfaces and transport systems in humans Study Guide
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