Aerobic respiration
Laura Armstrong & Joe Wolfensohn
Teachers
Recall Questions
This topic requires prior knowledge of respiration from KS3.
What is the word equation for aerobic respiration?
Glucose + oxygen → carbon dioxide + water ( + energy).
What is the main purpose of respiration?
To release energy.
Where in the cell does aerobic respiration take place?
In the mitochondria.
Topic Explainer Video
Check out these @JoeDoesBiology and @lauradoesbiology videos that explain aerobic respiration, then read the study notes. Once you’ve gone through them, don’t forget to try the practice questions!
What is Aerobic Respiration?
Aerobic respiration is a chemical reaction that takes place in all living cells. It releases energy from glucose using oxygen. As it releases energy, it is an exothermic reaction.
Word & Symbol Equation
Word equation:
Glucose + oxygen → carbon dioxide + water (+ energy)
Symbol equation:
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O
Glucose and oxygen are the reactants.
Carbon dioxide and water are the products.
Energy is not a product but is released when the reaction occurs. This is why we never say ‘energy is made’ but instead should always say ‘energy is released’.
Where It Happens
- Takes place in the mitochondria of cells.
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Requires oxygen, so it is an aerobic process (aerobic = with air).
What Is the Energy Used For?
The energy released is used for:
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Muscle contraction (movement).
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Active transport (e.g. in root hair cells).
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Building large molecules (e.g. making proteins).
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Maintaining body temperature in mammals.
Comparison with Photosynthesis
|
Process |
Reactants |
Products |
Energy |
|
Photosynthesis |
CO₂ + H₂O |
Glucose + O₂ |
Stored |
|
Respiration |
Glucose + O₂ |
CO₂ + H₂O |
Released |
No answer provided.
Key Terms
- Respiration - The process of releasing energy from glucose.
- Aerobic - A process that uses oxygen.
- Mitochondria - The part of the cell where aerobic respiration happens.
- Exothermic - A reaction that releases energy.
No answer provided.
Exam Tip
Don’t confuse respiration with breathing – respiration is a chemical reaction in cells, not taking air in and out of the lungs!
Never, ever say energy is made! Remember, energy cannot be created or destroyed!
No answer provided.
Practice Question
Describe what happens during aerobic respiration and give two ways the energy is used in the body. (5 marks)
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Aerobic respiration uses glucose and oxygen to release energy (1).
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It produces carbon dioxide and water (1).
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It takes place in the mitochondria of cells (1).
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It releases energy used for muscle contraction (1).
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And also for active transport in cells (1).
More Practice
Try to answer these practice questions from the TikTok videos on your own, then watch the videos to see how well you did!