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A plant cell wall was first observed and named (simply as a "wall") by Robert Hooke in 1665. [3] However, "the dead excrusion product of the living protoplast" was forgotten, for almost three centuries, being the subject of scientific interest mainly as a resource for industrial processing or in relation to animal or human health.
The cell wall acts to protect the cell mechanically and chemically from its environment, and is an additional layer of protection to the cell membrane. Different types of cell have cell walls made up of different materials; plant cell walls are primarily made up of cellulose, fungi cell walls are made up of chitin and bacteria cell walls are ...
During tip growth, cell walls are extended by the external assembly and polymerization of cell wall components, and the internal production of new cell membrane. [3] The Spitzenkörper is an intracellular organelle associated with tip growth. It is composed of an aggregation of membrane-bound vesicles containing cell wall components.
The cell wall is important for cell division, which, in most bacteria, occurs by binary fission. This process usually requires a cell wall and components of the bacterial cytoskeleton such as FtsZ. The ability of L-form bacteria and mycoplasmas to grow and divide in the absence of both of these structures is highly unusual, and may represent a ...
It is a primary component of cell walls in fungi (especially filamentous and mushroom-forming fungi), the exoskeletons of arthropods such as crustaceans and insects, the radulae, cephalopod beaks and gladii of molluscs and in some nematodes and diatoms. [2] [3] It is also synthesised by at least some fish and lissamphibians. [4]
The cell plate that is formed during cell division itself develops into middle lamella or lamellum. The middle lamella is made up of calcium and magnesium pectates. [2] In a mature plant cell it is the outermost layer of cell wall. [3] [4] In plants, the pectins form a unified and continuous layer between adjacent cells.
Neighbouring plant cells are therefore separated by a pair of cell walls and the intervening middle lamella, forming an extracellular domain known as the apoplast. Although cell walls are permeable to small soluble proteins and other solutes, plasmodesmata enable direct, regulated, symplastic transport of substances between cells. There are two ...
Light micrograph of a moss's leaf cells at 400X magnification. The following outline is provided as an overview of and topical guide to cell biology: . Cell biology – A branch of biology that includes study of cells regarding their physiological properties, structure, and function; the organelles they contain; interactions with their environment; and their life cycle, division, and death.