Download Bacteria are protected by a rigid cell wall composed of

Bacteria are protected by a rigid cell wall composed of peptidoglycans.
LEARNING OBJECTIVE [ edit ]
Memorize the characteristics of a bacterial cell wall
KEY POINTS [ edit ]
A cell wall is a layer located outside the cell membrane found in plants, fungi, bacteria, algae,
and archaea.
A peptidoglycan cell wall composed of disaccharides and amino acids gives bacteria structural
support.
The bacterial cell wall is often a target for antibiotic treatment.
TERM [ edit ]
binary fission
The process whereby a cell divides asexually to produce two daughter cells.
Give us feedback on this content: FULL TEXT [ edit ]
Bacterial cells lack amembranebound
nucleus. Theirgeneticmaterial is naked
within thecytoplasm. Ribosomes are their
only type of organelle. The term
"nucleoid" refers to the region of the
cytoplasm where chromosomal DNA is
located, usually a singular,
circularchromosome. Bacteria are usually
single­celled, except when they exist
in colonies. These ancestral cells
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reproduce by means of binary fission,
duplicating their genetic material and then essentially splitting to form two daughter cells
identical to the parent. A wall located outside the cell membrane provides the cell support,
and protection against mechanical stress or damage from osmotic rupture and lysis . The
major component of the bacterial cell wall ispeptidoglycan or murein. This rigid structure of
peptidoglycan, specific only to prokaryotes, gives the cell shape and surrounds the
cytoplasmic membrane. Peptidoglycan is a huge polymer of disaccharides (glycan) cross­
linked by short chains of identical amino acids(peptides) monomers. The backbone of the
peptidoglycanmolecule is composed of two derivatives of glucose: N­acetylglucosamine
(NAG) and N­acetlymuramic acid (NAM) with a pentapeptide coming off NAM and varying
slightly among bacteria. The NAG and NAM strands are synthesized in the cytosol of the
bacteria. They are connected by inter­peptide bridges. They are transported across the
cytoplasmic membrane by a carrier molecule called bactoprenol. From the peptidoglycan
inwards all bacterial cells are very similar. Going further out, the bacterial world divides into
two major classes: Gram positive (Gram +) and Gram negative (Gram ­). The cell wall
provides important ligands for adherence andreceptor sites for viruses or antibiotics.
Bacterial Cell Wall
The anatomy of bacterial cell structure.