Mitochondria are known as the "powerhouses" of the cell due to their main function, which is to generate energy in the form of adenosine triphosphate (ATP) through a process called cellular respiration. ATP is the primary energy currency of the cell and is essential for various cellular activities.

Mitochondria have an outer membrane and an inner membrane with numerous folds called cristae. These structures increase the surface area available for chemical reactions. Within the mitochondria, a series of enzymatic reactions occur in specialized compartments, such as the matrix and the inner mitochondrial membrane.

During cellular respiration, organic molecules, primarily glucose, are broken down in the presence of oxygen to produce ATP. This process involves several steps, including glycolysis, the Krebs cycle (also known as the citric acid cycle or TCA cycle), and oxidative phosphorylation.

Apart from ATP production, mitochondria are involved in other cellular processes. They play a crucial role in regulating cellular metabolism, calcium homeostasis, and the synthesis of certain biomolecules. Additionally, mitochondria are involved in programmed cell death, also known as apoptosis.

Overall, mitochondria are vital organelles in eukaryotic cells, providing energy for cellular functions and participating in various metabolic pathways.