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General reaction scheme for the S N 1 reaction. The leaving group is denoted "X", and the nucleophile is denoted "Nu–H". The unimolecular nucleophilic substitution (S N 1) reaction is a substitution reaction in organic chemistry.
The increased cell length can protect bacteria from protozoan predation and neutrophil phagocytosis by making ingestion of cells more difficult. [ 1 ] [ 3 ] [ 4 ] [ 5 ] Filamentation is also thought to protect bacteria from antibiotics, and is associated with other aspects of bacterial virulence such as biofilm formation.
Spiral bacteria are another major bacterial cell morphology. [2] [30] [31] [32] Spiral bacteria can be sub-classified as spirilla, spirochetes, or vibrios based on the number of twists per cell, cell thickness, cell flexibility, and motility. [33] Bacteria are known to evolve specific traits to survive in their ideal environment. [34]
Streptococcus is a genus of gram-positive or spherical bacteria that belongs to the family Streptococcaceae, within the order Lactobacillales (lactic acid bacteria), in the phylum Bacillota. [2] Cell division in streptococci occurs along a single axis , thus when growing they tend to form pairs or chains, which may appear bent or twisted.
In the Walden inversion, the backside attack by the nucleophile in an S N 2 reaction gives rise to a product whose configuration is opposite to the reactant. Therefore, during S N 2 reaction, 100% inversion of product takes place. This is known as Walden inversion. It was first observed by chemist Paul Walden in 1896.
Filamentous bacteriophages are a family of viruses (Inoviridae) that infect bacteria, or bacteriophages.They are named for their filamentous shape, a worm-like chain (long, thin, and flexible, reminiscent of a length of cooked spaghetti), about 6 nm in diameter and about 1000-2000 nm long.
The role of lipopolysaccharides here are verified from the observation that shorter O-side chains are more effectively transformed – perhaps because of improved DNA accessibility. The surface of bacteria such as E. coli is negatively charged due to phospholipids and lipopolysaccharides on its cell surface, and the DNA is also negatively charged.
Gram-negative bacteria are bacteria that, unlike gram-positive bacteria, do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. [1] Their defining characteristic is their cell envelope , which consists of a thin peptidoglycan cell wall sandwiched between an inner ( cytoplasmic ) membrane and an ...