The organelle responsible for energy production in both plants and animals is the mitochondrion.

Here's why:

* Mitochondria are often called the "powerhouses of the cell" because they are responsible for cellular respiration.

* Cellular respiration is the process of breaking down glucose (sugar) in the presence of oxygen to produce ATP (adenosine triphosphate), the primary energy currency of cells.

While plants do have chloroplasts, which are responsible for photosynthesis (converting light energy into chemical energy), they still rely on mitochondria for the majority of their energy needs.