Aerobic Respiration Revision Notes | GCSE OCR Foundation Biology

What this lesson covers

Explore aerobic respiration in detail, including the word equation and chemical symbols, and understand how oxygen is used to completely break down gluc...

• Explain the process of aerobic respiration using the word equation
• Write the balanced chemical equation for aerobic respiration using chemical symbols
• Compare aerobic respiration with photosynthesis
• Explain how aerobic respiration transfers energy from glucose

Key ideas to keep in view

Use this lesson to stay inside B1.3 Respiration while connecting the detail back to the wider B1: Cell level systems topic.

• B1: Cell level systems
• B1.3 Respiration
• GCSE OCR Foundation Biology

Lesson notes preview

Read the core explanations from Aerobic Respiration before testing yourself from memory.

• Right now, your heart is beating, your brain is thinking, and your muscles are working. All of this requires energy. But where does this energy come from? The answer lies in a process happening millions of times per second inside every living cell in your body.
• Your cells break down glucose (sugar) to release energy. This process needs oxygen from the air you breathe. Without it, you'd be unconscious in minutes. This energy-releasing process has a name: aerobic respiration.
• The process that releases energy from glucose using oxygen, producing carbon dioxide and water as waste products. It occurs continuously in living cells.
• Trap: Many students think respiration only happens when you breathe. Actually, breathing gets oxygen to your cells, but respiration is the chemical reaction inside cells that releases energy.
• Aerobic respiration can be summarised in a simple word equation. Think of it as a recipe - glucose and oxygen go in, energy comes out along with carbon dioxide and water.
• The word equation showing reactants and products of aerobic respiration
• Notice the arrow shows the direction - glucose and oxygen are used up (reactants) to make carbon dioxide and water (products). Energy is released during this process, though we don't show it in the equation.
• Exams expect you to know the chemical symbols for each substance in aerobic respiration. These symbols tell us exactly how many atoms of each element are involved.
• C₆H₁₂O₆ (glucose), O₂ (oxygen), CO₂ (carbon dioxide), H₂O (water)
• The numbers in front (6O₂, 6CO₂, 6H₂O) show how many molecules are needed to balance the equation. One glucose molecule needs six oxygen molecules and produces six carbon dioxide molecules and six water molecules.

Continue through the topic

Move to the related lessons or back to the topic page when you need the wider sequence before exam-style practice.