The part of the cell responsible for producing ATP is the mitochondrion. Often referred to as the "powerhouse" of the cell, mitochondria are involved in the process of anaerobic and aerobic respiration, converting biochemical energy into ATP through the oxidative phosphorylation pathway. The structure of mitochondria, featuring a double membrane and highly folded inner membrane, facilitates efficient energy production. ATP is vital for various cellular functions and processes, including muscle contraction, protein synthesis, and cell division.