Hydrogenosomen

Hydrogenosomes are specialized organelles found in certain anaerobic microorganisms, primarily fungi and ciliates. They are derived from mitochondria but have undergone significant evolutionary changes due to their adaptation to oxygen-deprived environments. Unlike typical mitochondria which perform aerobic respiration, hydrogenosomes are involved in anaerobic energy metabolism.

The primary function of hydrogenosomes is to produce hydrogen gas as a byproduct of their metabolic activity. This process often involves the fermentation of pyruvate, a product of glycolysis. During this fermentation, hydrogenosomes convert pyruvate into acetate, carbon dioxide, and molecular hydrogen. This hydrogen gas is then typically released from the cell.

The internal structure of hydrogenosomes differs from mitochondria. They generally lack a highly folded inner membrane (cristae) and often contain fewer internal proteins. Their size and morphology can vary depending on the organism. The specific metabolic pathways and substrates utilized by hydrogenosomes can also differ between species, reflecting their diverse ecological niches. The presence of hydrogenosomes is a key characteristic used in the classification of these anaerobic eukaryotes.