Prokaryotic Cell Biology - Structures external to the cell membrane The cell walls of Gram-positive and Gram-negative bacteria are very different from one another (Tortora et al., Figure 4.12)- Gram-positive bacteria are surrounded by a relatively thick layer of peptidoglycan (Tortora et al., Figure 4.12b) = Negatively-charged teichoic acids are covalently bound to the peptidoglycan = The teichoic acids probably assist in binding positively-charged molecules and surfaces to the cell- Gram-negative cells possess a much thinner layer of peptidoglycan, surrounded by an outer membrane (Tortora et al., Figure 4.12c) = Like the cytoplasmic membrane, the outer membrane is based on a phospholipid bilayer, and contains macromolecules unique to these bacteria · Lipoproteins consist of a lipid portion embedded in the "inner face" of the outer membrane and a protein portion covalently bound to the peptidoglycan; lipoproteins anchor the outer membrane to the peptidoglycan layer · Lipopolysaccharides (LPS)
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This note was uploaded on 01/23/2012 for the course MCB MCB2010 taught by Professor Smith during the Fall '09 term at Broward College.