Bacterial Cell Wall Structure
Location and Amount of Peptidoglycan in Gram+ vs. Gram- Bacteria
CLASS NOTES from Science Prof Online
Peptidoglycan (pep-tid-o-gly-can) is a molecule found only in bacterial cell walls The rigid structure of peptidoglycan gives the bacterial cell shape, surrounds the plasma membrane and provides prokaryotes
with protection from the environment.
Article Summary: The amount and location of peptidoglycan in the prokaryotic cell wall is what determines whether a bacterium is Gram-positive or Gram-negative.
Bacterial Cell Wall Structure: Gram + & Gram -
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Gram-positive Staphylococcus. Thick peptidoglycan cell wall retains crystal violet primary Gram stain. Go to >
Peptidoglycan is a huge polymer of interlocking chains composed of similar monomers. The backbone of the
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In Gram-positive cells, peptidoglycan makes up as much as 90% of the thick, compact cell wall, which is the outermost structure of Gram + cells.
peptidoglycan molecule is composed of two derivatives of glucose: NAG & NAM. Strands of NAG (N-acetylglucosamine) and NAM (N- acetylmuramic acid) are connected by interpeptide bridges.
See Page 2 for a diagram of the Gram-negative cell wall and a video on Gram Staining!