BIOL 2200 Chapter Notes - Chapter 567-577; 581-584: Gram Staining, Crystal Violet, Plasmolysis
19 Feb 2017
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Because prokaryotes can adapt to nearly any habitat, they have become the most abundant organisms on this planet. Most prokaryotes are unicellular, except for some species that remain attached to each other after cell division. Can come in a variety of shapes. Nearly all prokaryotes have a cell wall to: And prevent it from bursting in a hypotonic environment. Most prokaryotes plasmolyze and are inhibited from reproducing in hypertonic environments. Archaeal cell walls contain polysaccharides and proteins, but no peptidoglycan. Gram stain = used to categorize bacterial species based on differences in cell wall composition. Samples are first stained with crystal violet dye and iodine, rinsed with alcohol, and then stained with red dye. Gram-positive = simple cell walls with a lot of peptidoglycan. Gram-negative = more complex, with an outer membrane containing lipopolysaccharides. Harder to treat in that the lipids cause fever and shock, and is resistant to drugs and treatment.
