Membranständigen

Membranständigen describes organelles and other structures of a cell that are enclosed by one or more lipid membranes. In cell biology, membranständige Organellen form the compartmental architecture of eukaryotic cells, enabling specialized environments for distinct biochemical reactions. Prokaryotic cells generally lack such membrane-bound compartments.

Common membranständige Organellen include the nucleus (double membrane surrounding genetic material), mitochondria (double membrane and own genome), chloroplasts in plants and algae (double membrane and own genome), the endoplasmic reticulum and Golgi apparatus (continuous membranes forming the endomembrane system), lysosomes and peroxisomes (single membranes), and various vesicles and vacuoles. Some organelles have two membranes (nucleus, mitochondria, chloroplasts); others have a single limiting membrane yet are folded or interconnected within a network.

Functionally, membranes create distinct biochemical environments, regulate material exchange via transport proteins, and enable targeted localization of enzymes and substrates. They also support processes such as energy production, macromolecule synthesis, storage, and waste processing. The most widely accepted explanation for the origin of mitochondria and chloroplasts is endosymbiosis, supported by evidence including circular DNA, ribosomes resembling bacterial genomes, and double membranes.

In contrast, membranständige structures are contrasted with membranunabhängige components, such as ribosomes floating freely in the cytosol or cytoskeletal filaments, which are not enclosed by a lipid bilayer. This article uses membranständigen structures as a conventional German description of membrane-bound cellular components.