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Microbiology

  • Ahmad Wagih Abdel (Halim)
Chapter

Bacteria

  • All bacteria are haploid structures; they can trap iron using siderophores, and can also perform fermentation processes.

  • Gram-positive bacteria appear violet because they absorb cresyl violet stain.

  • Gram-negative bacteria appear red because they absorb safranin stain.

  • Cell wall of bacteria is mainly made up of peptidoglycan:
    1. 1.

      Gram positive: It is thick with extensive cross-linking.

       
    2. 2.

      Gram negative: It is thin with minimal cross-linking.

       

Structure

Gram-Positive Bacteria

  • Cell envelope from inside out is formed of two layers:
    1. 1.

      Cytoplasmic membrane: A lipid bilayer spanned by proteins. This layer, unlike animals’ membranes, contains no sterols.

       
    2. 2.

      Cell wall: Formed of 3 P’s—Peptidoglycan, Polysaccharides, Proteins—and an antigenic determinant known as teichoic acid.

       

Gram-Negative Bacteria

  • Cell envelope from inside out is formed of three layers:
    1. 1.

      Cytoplasmic membrane: Lipid bilayer spanned by proteins

       
    2. 2.

      Cell wall: Very thin peptidoglycan layer with no teichoic...

Keywords

Human Immunodeficiency Virus Clinical Picture Toxic Shock Syndrome Tinea Capitis Benzathine Penicillin 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  1. 1.McLaren Regional Medical CenterFlintUSA

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