Photosynthesis is the process plants, algae, and some bacteria use to turn light energy into chemical energy stored in sugar.
### The basic equation
\[
6CO_2 + 6H_2O + \text{light energy} \rightarrow C_6H_{12}O_6 + 6O_2
\]
In words:
**Carbon dioxide + water + sunlight → glucose + oxygen**
### Where it happens
In plants, photosynthesis mainly occurs in the **chloroplasts** of leaf cells. Chloroplasts contain **chlorophyll**, the green pigment that absorbs sunlight.
### The two main stages
1. **Light-dependent reactions**
- Chlorophyll absorbs sunlight.
- Water molecules are split.
- Oxygen is released as a byproduct.
- Light energy is converted into temporary chemical energy.
2. **Calvin cycle**
- The plant uses that chemical energy to combine carbon dioxide into glucose and other carbohydrates.
- These carbohydrates can be used for energy, growth, or storage.
### Why it matters
Photosynthesis:
- Produces much of the oxygen we breathe.
- Removes carbon dioxide from the atmosphere.
- Creates food for plants, forming the base of most food chains.
- Stores solar energy in a form living organisms can use.
A simple way to remember it is: **plants use sunlight to make food from water and carbon dioxide, releasing oxygen along the way.**