Where Does Energy Come From?

All living things need energy. Cellular respiration is how cells turn food into energy they can use.

The Process

Cells take in glucose and oxygen. Through a series of steps, they break glucose down and make energy molecules called ATP (adenosine triphosphate).

\[ \text{C}6\text{H}{12}\text{O}_6 + 6\text{O}_2 \rightarrow 6\text{CO}_2 + 6\text{H}_2\text{O} + \text{ATP} \]

Why Is This Important?

Without cellular respiration, muscles couldn’t move, brains couldn’t think, and plants couldn’t grow. ATP is like the “battery” that powers everything in a cell.

Types of Respiration

• Aerobic Respiration: Uses oxygen, makes lots of ATP.
• Anaerobic Respiration: No oxygen needed, makes less ATP (like when muscles get tired).