Final answer:
The mitochondrion is the cell organelle responsible for producing energy in the form of ATP, acting as the cell's 'power plant.'
Step-by-step explanation:
The organelle that provides energy for the cell is the mitochondrion (plural, mitochondria). These are often described as the "power plants" or "energy factories" of the cell. Mitochondria are responsible for taking energy from organic compounds, such as glucose, and converting it into adenosine triphosphate (ATP), which is an energy-carrying molecule cells use for various functions including movement and cell division. Cells with higher energy needs, like muscle cells, contain many mitochondria to meet their demands.