Which organelle is the powerhouse of the cell?

• A. Nucleus
• B. Mitochondria
• C. Lysosomes
• D. Cytoplasm

Answer: (B)

Mitochondria are the powerhouse of the cell because they generate most of the cell’s ATP, the energy currency cells use for work. This energy production happens mainly through cellular respiration inside mitochondria, involving glycolysis in the cytoplasm to break down glucose, followed by pyruvate processing, the citric acid cycle, and oxidative phosphorylation where ATP is actually synthesized. The inner membrane cristae provide a large surface area for the electron transport chain and ATP synthase to function efficiently, making the process highly productive.

The nucleus, in contrast, is the control center that stores genetic material and regulates gene expression. Lysosomes act as recycling centers, breaking down waste and damaged components. The cytoplasm is the jelly-like fluid where many metabolic reactions occur, including glycolysis, but it’s not where the majority of ATP is produced.