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Year 9 - Science

Breathing, respiration and gas exchange

Breathing and respiration

Unit Summary

This unit explores the human gas exchange system, breathing mechanisms, and adaptations for function. It covers aerobic and anaerobic respiration, including fermentation, and compares their processes and implications. Focus is on accuracy, reliable measurements, and SI units.

Lesson Summary

You will learn to describe the differences between breathing, respiration and gas exchange.

Key Notes

  • Humans and other animals breathe to move air in and out of their lungs.
  • Cells need oxygen from the air for cellular respiration, to provide energy for life processes.
  • Cellular respiration produces carbon dioxide as a waste product.
  • Oxygen needs to be absorbed into, and carbon dioxide needs to be removed from, the human body.
  • In gas exchange, oxygen diffuses from the lungs into the blood; carbon dioxide diffuses from the blood into the lungs.

Vocabulary To Learn

  • breathing: Breathing is the process in which air moves in and out of the lungs.
  • lungs: The lungs are a pair of organs found in humans and some other animals.
  • cellular respiration: Cellular respiration is a chemical process in cells, which uses sugar as a fuel to provide energy for life processes.
  • mitochondria: Subcellular structures, called mitochondria, use sugar and oxygen for cellular respiration.
  • gas exchange: The process of oxygen diffusing from the lungs to the blood and carbon dioxide diffusing from the blood to the lungs is called gas exchange.

Common Mistakes To Avoid

  • Breathing and respiration are the same thing.

3 Quick Questions (With Answers)

1. Explain the scientific idea in this lesson using two key points.

Humans and other animals breathe to move air in and out of their lungs. Cells need oxygen from the air for cellular respiration, to provide energy for life processes.

2. Define this scientific word and use it in context. 'breathing'

Breathing is the process in which air moves in and out of the lungs. Include the word in a full scientific explanation, not as a single label.

3. Correct this common scientific misunderstanding.

Mistake: Breathing and respiration are the same thing. Correction: This lesson explores the differences between breathing, respiration and gas exchange, including what they are and where they take place.

More Lessons In This Unit

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