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A cell wall is a structural layer that surrounds some cell types, found immediately outside the cell membrane.It can be tough, flexible, and sometimes rigid. Primarily, it provides the cell with structural support, shape, protection, and functions as a selective barrier. [1]
Some eukaryotic cells (plant cells and fungal cells) also have a cell wall. Inside the cell is the cytoplasmic region that contains the genome (DNA), ribosomes and various sorts of inclusions. [2] The genetic material is freely found in the cytoplasm. Prokaryotes can carry extrachromosomal DNA elements called plasmids, which are usually circular.
The bacterial cell wall differs from that of all other organisms by the presence of peptidoglycan (poly-N-acetylglucosamine and N-acetylmuramic acid), which is located immediately outside of the cytoplasmic membrane. Peptidoglycan is responsible for the rigidity of the bacterial cell wall and for the determination of cell shape. It is ...
Fimbriae usually function to facilitate the attachment of a bacterium to a surface (e.g. to form a biofilm) or to other cells (e.g. animal cells during pathogenesis). A few organisms (e.g. Myxococcus ) use fimbriae for motility to facilitate the assembly of multicellular structures such as fruiting bodies .
In many archaeal species the S-layer is the only cell wall component and, therefore, is important for mechanical and osmotic stabilization. The S-layer is considered to be porous, which contributes to many of its functions. [10] Additional functions associated with S-layers include: protection against bacteriophages, Bdellovibrios, and phagocytosis
Cell walls perform many essential functions. They provide shape to form the tissue and organs of the plant, and play an important role in intercellular communication and plant-microbe interactions. [1] The cell wall is flexible during growth and has small pores called plasmodesmata that allow the exchange of nutrients and hormones between cells ...
Cell biology (also cellular biology or cytology) is a branch of biology that studies the structure, function, and behavior of cells. [1] [2] All living organisms are made of cells. A cell is the basic unit of life that is responsible for the living and functioning of organisms. [3] Cell biology is the study of the structural and functional ...
The pit aperture is the opening at either end of the pit chamber. The pit membrane is the primary cell wall and middle lamella, or the membrane between adjacent cell walls, at the middle of the pit chamber. [2] The primary cell wall at the pit membrane may also have depressions similar to the pit depressions of the secondary layers.