Life's Chemistry Set

Cells need energy to survive, and they use intricate chemical pathways to get it. Together, these pathways are called metabolism.

ATP: The Energy Currency

The primary energy molecule used by cells is adenosine triphosphate (ATP). Cells generate ATP through:

• Glycolysis: Breaks down glucose into pyruvate, yielding a small amount of ATP.
• Citric Acid Cycle (Krebs Cycle): Produces high-energy molecules (NADH, FADH₂) for the next step.
• Electron Transport Chain (ETC): Uses electrons from NADH and FADH₂ to generate lots of ATP.

The overall equation for cellular respiration: \[ \text{C}6\text{H}{12}\text{O}_6 + 6\ \text{O}_2 \rightarrow 6\ \text{CO}_2 + 6\ \text{H}_2\text{O} + \text{Energy} (ATP) \]

Metabolism in Action

When you eat, carbohydrates, fats, and proteins are broken down and converted into ATP, powering everything you do—from thinking to running!

Cellular Respiration vs. Fermentation

• Aerobic respiration: Requires oxygen, produces lots of ATP.
• Anaerobic fermentation: Occurs without oxygen, yields less ATP but is essential in low-oxygen situations (like sprinting).