What is the powerhouse of the cell?

The mitochondrion (plural: mitochondria) is often referred to as the "powerhouse of the cell" because it is the primary site of cellular respiration. This is the metabolic process that generates most of the cell's supply of adenosine triphosphate (ATP), which is used as a source of chemical energy.

Mitochondria are complex organelles with a double-membraned structure. The outer membrane is smooth, while the inner membrane is highly folded into structures called cristae. These cristae increase the surface area available for the reactions of cellular respiration.

The process of ATP generation primarily occurs within the inner mitochondrial membrane and the mitochondrial matrix, the space enclosed by the inner membrane. Key processes that take place here include:

• Electron Transport Chain (ETC): A series of protein complexes that transfer electrons and pump protons to create an electrochemical gradient. [https://www.wikiwhat.page/kavramlar/Electron%20Transport%20Chain%20(ETC)]

• Oxidative Phosphorylation: The process by which ATP synthase uses the proton gradient generated by the ETC to produce ATP. [https://www.wikiwhat.page/kavramlar/Oxidative%20Phosphorylation]

• Krebs Cycle (Citric Acid Cycle): A series of chemical reactions that extract energy from molecules, releasing carbon dioxide and generating high-energy electron carriers (NADH and FADH2) which are used in the ETC. [https://www.wikiwhat.page/kavramlar/Krebs%20Cycle%20(Citric%20Acid%20Cycle)]

Mitochondria also play roles in other cellular processes, including:

• Apoptosis (Programmed Cell Death): Mitochondria can initiate programmed cell death. [https://www.wikiwhat.page/kavramlar/Apoptosis%20(Programmed%20Cell%20Death)]

• Calcium Signaling: Mitochondria can regulate calcium levels within the cell. [https://www.wikiwhat.page/kavramlar/Calcium%20Signaling]

Mitochondria possess their own DNA (mitochondrial DNA - mtDNA) and ribosomes, suggesting an endosymbiotic origin. This means that they are believed to have evolved from ancient bacteria that were engulfed by early eukaryotic cells. [https://www.wikiwhat.page/kavramlar/mitochondrial%20DNA%20-%20mtDNA]