Which component of a cell is involved in the production of ATP?

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

Answer: (A)

The mitochondria are often referred to as the "powerhouses" of the cell because they are the primary sites of ATP production through the process of oxidative phosphorylation. Inside the mitochondria, the Krebs cycle (or citric acid cycle) occurs in the matrix, and the electron transport chain takes place across the inner mitochondrial membrane. During these processes, nutrients are oxidized, and energy released is used to convert adenosine diphosphate (ADP) and inorganic phosphate into adenosine triphosphate (ATP), which cells use as a direct source of energy for various biological processes.

Ribosomes are responsible for protein synthesis, translating messenger RNA into polypeptides, and do not produce ATP. The nucleus is the control center of the cell, housing genetic material and coordinating activities like growth and reproduction, but does not engage in ATP production. Lysosomes are involved in breaking down waste materials and cellular debris but do not contribute to ATP synthesis either. Hence, the mitochondria are uniquely designated for this critical function of energy production in the form of ATP.