1.energy is released by a biological process called respiration......in cellular respiration(break down of food inside the cells with release of energy)first of all food present in the cell's cytoplasm food is converted into pyruvate (pyruvic acid)[in absence of oxygen] and then it goes into mitochondria where pyruvate is oxidised by oxygen into CO2 and H2O with energy rich 38 ATPs...(energy is stored in ATPs)......and this whole process is called AEROBIC RESPIRATION there is another type respiration also called ANAEROBIC RESPIRATION in which energy is released not in mitochondria and without oxygen but according to ur question....its all

Mitochondria

Mitochondria are known as the powerhouse of the cell because they release energy in the form of ATP (adenosine triphosphate) through a process called cellular respiration. Here's how mitochondria release energy:

- Cellular Respiration: Mitochondria perform aerobic respiration, a process that converts glucose and oxygen into ATP, carbon dioxide, and water. This process occurs in several stages, including glycolysis, the Krebs cycle, and the electron transport chain.

- ATP Production: During cellular respiration, ATP is produced as a result of the breakdown of glucose molecules. ATP is the primary energy currency of the cell and is used for various cellular processes and functions.

- Structure: Mitochondria have a double membrane structure with an inner membrane that forms folds called cristae. The inner membrane is where the electron transport chain takes place, leading to the production of ATP.

- Importance: The energy released by mitochondria is essential for the survival and functioning of cells. Without this energy production, cells would not be able to carry out their metabolic activities efficiently.

In conclusion, mitochondria are responsible for releasing energy in the form of ATP through the process of cellular respiration. Their unique structure and function make them vital organelles in the cell.