What is Photosynthesis?

Introduction

Photosynthesis is one of the most important processes in nature. It is how plants, algae, and some bacteria make their own food using sunlight, water, and carbon dioxide. Thanks to photosynthesis, we have oxygen to breathe and food to eat!

1. What is Photosynthesis?

Photosynthesis is the process by which green plants convert light energy into chemical energy. This chemical energy is stored in the form of glucose (a type of sugar), which the plant uses for growth and energy.

2. The Photosynthesis Equation

The process can be summarized in one simple equation:

6CO₂ + 6H₂O + sunlight → C₆H₁₂O₆ + 6O₂

This means: six molecules of carbon dioxide + six molecules of water, with sunlight energy, produce glucose and oxygen.

3. Where Does Photosynthesis Happen?

Photosynthesis happens inside the chloroplasts of plant cells. Chloroplasts contain a green pigment called chlorophyll, which captures light energy from the sun.

4. The Two Stages of Photosynthesis

• Light Reactions: These happen in the thylakoid membranes. The plant captures sunlight and uses it to split water molecules, releasing oxygen.
• Calvin Cycle (Dark Reactions): These happen in the stroma. The plant uses carbon dioxide and the energy from light reactions to produce glucose.

5. Why Photosynthesis is Important

• Provides oxygen for animals and humans to breathe.
• Forms the base of the food chain — plants feed herbivores, which feed carnivores.
• Removes carbon dioxide from the atmosphere, helping balance Earth’s climate.

6. Fun Facts

• Without photosynthesis, life on Earth would not exist.
• Amazon rainforest produces about 20% of Earth’s oxygen.
• Some bacteria can perform photosynthesis without chlorophyll!

7. Summary

Photosynthesis is the process that powers life on Earth. By using sunlight, plants create food and oxygen, supporting all living beings. Understanding it helps us appreciate the beauty of nature — and the science that keeps us alive.