mitokondrernas

Mitochondria are often referred to as the "powerhouses" of the cell. These are membrane-bound organelles found in the cytoplasm of eukaryotic cells. 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.

The structure of a mitochondrion is characterized by a double membrane. The outer membrane is smooth, while the inner membrane is extensively folded into structures called cristae. These cristae significantly increase the surface area of the inner membrane, which is crucial for the efficiency of ATP synthesis. The space enclosed by the inner membrane is called the mitochondrial matrix, which contains enzymes, ribosomes, and mitochondrial DNA.

Mitochondria have their own circular DNA, called mitochondrial DNA (mtDNA), which is separate from the nuclear DNA. This mtDNA is inherited maternally in most organisms. The presence of their own DNA and ribosomes suggests that mitochondria may have originated from free-living bacteria that were engulfed by early eukaryotic cells in a symbiotic relationship, a theory known as the endosymbiotic theory.

Beyond energy production, mitochondria are involved in various other cellular processes, including calcium homeostasis, programmed cell death (apoptosis), and the synthesis of certain steroids and heme. Their dysfunction is implicated in a wide range of diseases, including neurodegenerative disorders, metabolic diseases, and cancer.