Rakukestuse

Rakukestuse is a term of Estonian origin that translates to "cell membrane" or "cell wall" in English, depending on the context. In biological sciences, it refers to the outer boundary of a cell. The primary function of the rakukestuse is to enclose and protect the internal contents of the cell, separating it from its external environment.

The specific structure of the rakukestuse varies significantly between different types of cells. For instance, in animal cells, it is a flexible plasma membrane composed of a phospholipid bilayer embedded with proteins. This membrane is selectively permeable, controlling the passage of substances into and out of the cell. In plant cells, fungi, and bacteria, an additional, more rigid layer called a cell wall is present outside the plasma membrane. This cell wall provides structural support and protection against mechanical stress and osmotic lysis. In plant cells, the cell wall is primarily made of cellulose, while in fungi it is composed of chitin. Bacterial cell walls have a peptidoglycan structure. Therefore, the precise composition and properties of the rakukestuse are crucial for understanding the cell's function and its interaction with its surroundings.