Humans and other animals need oxygen to burn food in their bodies. When we eat, carbohydrates and oxygen are converted into carbon dioxide, water and energy that cells can use as fuel. This process is called cellular respiration, like reverse photosynthesis (1). Plants also have cellular respiration to extract energy from the carbohydrates needed for the plant to live. But oxygen remains left over from photosynthesis, accumulating in the atmosphere and allowing us to live here on Earth (2).
Cellular respiration: glucose + oxygen → carbon dioxide + water + energy.
Sources
- Naturskyddsföreningen – The water cycle and photosynthesis
- Biology Dictionary – Cellular Respiration and Photosynthesis
October 2023, TÄNKOM | Revised November 2023 RETHINK
