mitokondioiden

Mitochondria are often referred to as the "powerhouses" of the cell. These organelles are found in nearly all eukaryotic cells, including those of plants, animals, fungi, and protists. Their primary function is to generate most of the cell's supply of adenosine triphosphate (ATP), which is used as a source of chemical energy. This process is known as cellular respiration.

Structurally, mitochondria are enclosed by two membranes. The outer membrane is smooth and acts as a barrier. The inner membrane is highly folded into structures called cristae, which significantly increase the surface area. These cristae house the enzymes and protein complexes involved in the electron transport chain and ATP synthesis. The space enclosed by the inner membrane is called the mitochondrial matrix, which contains enzymes, ribosomes, and mitochondrial DNA.

Mitochondria have a unique origin. It is widely accepted that they evolved from free-living bacteria that were engulfed by an ancestral eukaryotic cell in a process called endosymbiosis. This theory is supported by the fact that mitochondria possess their own circular DNA, distinct from the cell's nuclear DNA, and they can replicate independently. They also have their own ribosomes, similar to those found in bacteria.

Beyond energy production, mitochondria play roles in other cellular processes, including calcium homeostasis, programmed cell death (apoptosis), and the synthesis of certain steroids and heme. Dysfunctions in mitochondrial activity are linked to a variety of diseases, including neurodegenerative disorders, metabolic diseases, and aging.