Dec '08
MCAT Question of the Day | MCAT Course

  • Q:

    Gram staining is a common technique utilized for classification of bacteria. Gram-positive bacteria, when stained, appear purple under the microscope, while Gram-negative bacteria do not. This provides a simple method to organize bacteria. The difference between Gram-positive and Gram-negative bacteria is that



    Gram-positive and Gram-negative bacteria differ in receptor molecules on the cell membrane. Gram-positive bacteria have receptors that induce the translation of a purple gene.


    The bacteria have different thicknesses of the peptidoglycan cell wall. Gram-positive bacteria have a thicker cell wall thus the stain does not leave the cell once it has entered and reacted with the iodine solution.


    The bacteria have different hydrolytic enzymes that digest the stain molecules.


    The Gram-positive bacteria possesses a cell wall while the other does not.

    Tags: Prokaryotes | Suggest a tag


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