The organelle that produces the energy needed by the cell is the mitochondrion.

Here's why:

* Mitochondria are the "powerhouses" of the cell. They are responsible for cellular respiration, which is the process of converting glucose (sugar) into ATP (adenosine triphosphate). ATP is the primary energy currency of cells.

* Cellular respiration involves a series of chemical reactions that break down glucose and release energy. This energy is then used to produce ATP.

* Mitochondria have their own DNA and ribosomes, which allows them to produce some of their own proteins.

Let me know if you'd like to know more about mitochondria or cellular respiration!