structure of Bacteria - The Veterinary Site

structure of Bacteria


Bacteria
(by MAAZ AHMED SIDDIQUI)

  Bacteria are Prokaryotes – No nucleus or organelles bound in membranes
  DNA is a single circular chromosome
  No Histones associated with DNA
  Cell Walls of peptidoglycan (polymer of NAG and NAM cross-linked with polypeptide chain)
  Smaller ribosome unit
  Divide by binary fission (not mitosis)
Structures External to the Cell Wall
  Glycocalyx
  Many prokaryotes secrete on their surface a substance called glycocalyx.
  Glycocalyx (meaning sugar coat) is the general term
used for substances that surround cells.
  The bacterial glycocalyx is a viscous (sticky), gelatinous polymer that is external to the cell wall and composed of polysaccharide, polypeptide, or both.
  Its  chemical composition varies widely with the species. For the most part, it is made inside the cell and secreted to the cell surface.
  If the substance is organized and is firmly attached to the cell wall , the glycocalyx is described as a capsule.
  If the substance is unorganized and only loosely attached to the cell wall, the glycocalyx is described as a slime layer
  Flagella
  Some prokaryotic cells have flagella (singular: flagellum ),
which are long filame ntous appendages that propel bacteria.
Bacteria that lack flagella are referred to as atrichous (without projections).
  Flagella may be peritrichous (distributed over the
entire cell or polar (at one or both poles or ends of
the cell). If polar, flagella may be monotrichous (a single flagellum at one pole) lophotrichous (a tuft of flagella coming from one pole), or amphitrichous (flagella
at both poles of the cell) .


structure of Bacteria structure of Bacteria Reviewed by Maaz ahmed siddiqui on 07 May Rating: 5

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