Final answer:
Most of the energy produced in cellular respiration is generated in the mitochondria during the oxidative phosphorylation stage, producing ATP and emitting carbon dioxide as byproduct.
Step-by-step explanation:
The energy in cellular respiration is primarily produced in the mitochondria. These organelles are often referred to as the 'powerhouses' or 'energy factories' of a cell. The process of making ATP (adenosine triphosphate), which is the main energy-carrying molecule of the cell, occurs here. Cellular respiration includes several stages, but the majority of ATP is generated through a step called oxidative phosphorylation, which occurs within the mitochondria. This phase involves an electron transport system (ETS) and produces up to 90 percent of the ATP after the complete breakdown of glucose. Oxygen is required for this process and carbon dioxide is released as a waste product.