ulkokalvolla

Ulkokalvolla is a Finnish biological term used to describe the localization of a molecule on the outer membrane of a cell or organelle, or to denote the outer membrane itself in Finnish scientific writing. It is formed from ulk- meaning outer and kalvo meaning membrane, with the adessive suffix -lla indicating 'on' or 'at'.

In bacterial contexts, ulkokalvolla commonly refers to the outer membrane of Gram-negative bacteria, an asymmetric bilayer containing lipopolysaccharide on the outer face and phospholipids on the inner face. Outer membrane proteins such as porins reside there and contribute to permeability, while lipoproteins anchor to the membrane. Outer membrane vesicles can bud from this surface and participate in pathogenesis and intercellular communication.

In eukaryotic organelles, the term can describe components associated with the outer mitochondrial membrane or the outer envelope of chloroplasts. The outer mitochondrial membrane contains porins (VDACs) and other proteins involved in metabolite exchange; protein import pathways involve translocase complexes such as TOM and TIM for trafficking to internal compartments.

Methods to study ulkokalvolla localization include subcellular fractionation, immunolocalization, and fluorescence microscopy, often combined with proteomic analysis of membrane-enriched fractions. The term is primarily used in Finnish-language scientific writing and may appear in textbooks, primary research articles, and data annotations to indicate surface localization.

Related topics include the cell membrane and other organelle membranes.