Välismembraaniga

Välismembraaniga refers to the outer membrane of a cell. In prokaryotic cells, such as bacteria, the outer membrane is a distinct lipid bilayer located outside the peptidoglycan layer. This membrane contains lipopolysaccharides, which are important components of the Gram-negative bacterial cell wall and can act as endotoxins. The outer membrane provides an additional barrier, protecting the cell from harmful substances and maintaining its shape. It also contains porins, which are protein channels that allow the passage of small molecules into and out of the cell.

In eukaryotic cells, the term "välismembraaniga" generally refers to the plasma membrane, which is the outermost boundary of the cell. This membrane encloses the cytoplasm and regulates the transport of substances into and out of the cell. It is composed of a phospholipid bilayer with embedded proteins, cholesterol, and carbohydrates. The plasma membrane plays crucial roles in cell signaling, cell adhesion, and maintaining the cell's internal environment. The term can also be used in the context of organelles within eukaryotic cells that are enclosed by membranes, such as the outer membrane of mitochondria or the nuclear envelope.