Prokaryotic Cells YouTube Lecture Handouts for CBSE Board Exam
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Shape, Structure & Components Gram Positive and Gram Negative Bacteria
In Gram-positive bacteria, peptidoglycan makes up as much as 90% of the thick cell wall enclosing the plasma membrane.
Two groups of bacteria devoid of cell wall peptidoglycans are the Mycoplasma species, which possess a surface membrane structure, and the L-forms that arise from either Gram-positive or Gram-negative bacterial cells that have lost their ability to produce the peptidoglycan structures.
Both Gram-positive and Gram-negative bacteria possess cell wall peptidoglycans confer the characteristic cell shape and provide the cell with mechanical protection.
Teichoic acids are covalently linked to the peptidoglycan in some Gram-positive bacteria.
Most Gram-positive bacteria have a relatively thick, continuous cell wall, which is composed largely of peptidoglycan.
Both Gram-positive and Gram-negative bacteria take up the same amounts of crystal violet (CV) and iodine (I) which is trapped inside the Gram-positive cell by the dehydration and reduced porosity of the thick cell