Which organelle is commonly referred to as the powerhouse of the cell?

• A. Mitochondria
• B. Nucleus
• C. Endoplasmic Reticulum
• D. Lysosome

Answer: (A)

The energy backbone of the cell comes from organelles that convert nutrients into usable energy. Mitochondria generate most of the cell’s ATP, the energy currency, through cellular respiration. They house the enzymes of the citric acid cycle in the matrix and the electron transport chain on the inner membrane, where the majority of ATP is produced as electrons flow and power the phosphorylation of ADP to ATP. Their own DNA and ribosomes reflect their bacterial origins and support their role in energy metabolism.

In contrast, the nucleus stores genetic material; the endoplasmic reticulum handles protein and lipid synthesis and folding; lysosomes break down waste materials. So, the mitochondrion is the organelle most closely associated with supplying the cell’s energy, earning its nickname as the powerhouse.