cell wall


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wall

 [wawl]
a structure bounding or limiting a space or a definitive mass of material; called also paries.
cell wall a rigid structure that lies just outside of and is joined to the plasma membrane of plant cells and most prokaryotic cells, which protects the cell and maintains its shape.
chest wall the structures bordering the thorax that move during breathing, including the rib cage, diaphragm, and abdomen.

cell wall

1. the outer layer or membrane of some animal and plant cells; in the latter, it is mainly cellulose.
2. in bacteria, the rigid structure, usually containing a peptidoglycan layer, that provides osmotic protection and defines bacterial shape and staining properties.

cell wall

n.
The rigid outermost cell layer found in plants and certain algae, bacteria, and fungi but absent from animal cells.

cell wall

(sel wawl)
The outer layer or membrane of some animal and plant cells; in the latter, it is mainly cellulose.

cell wall

a thick, rigid coat formed outside the CELL MEMBRANE of plants, fungi and most bacteria. The cell wall is responsible for the shape of the organism and for protecting internal parts of the cell from damage. The plant cell wall is composed mainly of CELLULOSE secreted by the protoplasm of the cell. Structurally it consists of cellulose fibres embedded in a matrix of pectin and other polysaccharides, rather like fibreglass. Each fibre is built up from cellulose molecules which form strands called micelles. These are grouped into microfibrils, several hundred of which form a fibre. Older cells may also produce a secondary wall inside the primary wall which is thicker and contains LIGNIN for extra strength. Such cells often die after producing the secondary wall, e.g. XYLEM vessel cells.

The cell wall of BACTERIA is made of PEPTIDOGLYCAN, either alone or combined with other substances, and is used to differentiate the major types of bacteria: Gram-positive and Gram-negative (see GRAM'S STAIN). In Gram-positive bacteria, the wall generally consists of many layers of peptidoglycan, giving a very rigid structure. TEICHOIC ACIDS are also present. In Gram-negative bacteria there is a thin layer of peptidoglycan and an outer membrane. The peptidoglycan is attached to LIPOPROTEINS in the outer membrane. This membrane acts as a barrier to some ANTIBIOTICS, ENZYMES and so on; however, certain substances, such as nutrients, pass through. Part of the permeability of the membrane is due to PORINS. The ARCHAEA either lack cell walls or have unusual walls without peptidoglycan. In FUNGI a key component of most cell walls is CHITIN. The cell walls of YEASTS contain glucan and mannan. There may be additional layers, such as a CAPSULE, outside the cell wall.

cell wall

(sel wawl)
1. Outer layer or membrane of some animal and plant cells.
2. In bacteria, the rigid structure that provides osmotic protection and defines bacterial shape and staining properties.
References in periodicals archive ?
In order to access the energy-rich sugars found in the plant cell walls, researchers have renewed focus on solvating lignin, a complex polymer also found in plant cell walls that acts as a natural shield, blocking both chemical and biological attack.
An advantage of nanoindentation is its ability to probe small volumes of materials, such as the wood cell wall layers S2 and CCML (Wimmer and Lucas 1997).
VND6 and VND7 directly regulate genes for both secondary cell wall formation and PCD through binding to the tracheary element-specific cis element TERE in their promoters.
The introduced gold nanoparticles in peptidoglycan will disturb crystalline process of peptidoglycan by forming amorphous region around them, which will reduce the capacity to resist pressure from inside of cell walls. Usually peptidoglycan has a crystalline structure that is resistant against high osmotic pressure inside the cell, which may reach 20 atmospheres in the case of gram-positive bacteria [5].
(2013), strain NCCP-54T contained Lys-Asp as a diagnostic amino acids in cell wall peptidoglycans, which corresponds to variation type A4a.
Cell wall disruption, viability and sorbitol protection assays
The family of wall-associated kinases was widely investigated as potential candidate for a cell wall "sensor" [42].
In addition, several solid alloys of compositions roughly corresponded to those formed in the cell wall materials of the studied Al-foams were fabricated by casting to use them in the experimentation.
The cell walls form the structural supports of all plants.
Harvard and Evotec will identify and optimize small molecule inhibitors of bacterial cell wall synthesis based on enabling technologies and chemical starting points licensed from Harvard.
It turns out the large range in stiffness and strength stems from an intricate combination of plant microstructures: the composition of the cell wall the number of layers in the cell wall the arrangement of cellulose fibers in those layers, and how much space the cell wall takes up, she said.
It turns out the large range in stiffness and strength stems from an intricate combination of plant microstructures: the composition of the cell wall, the number of layers in the cell wall, the arrangement of cellulose fibres in those layers, and how much space the cell wall takes up.