MCAT Question of the Day
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    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
    		 

    A

    		 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.

    B

    		 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.

    C

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

    D

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



    Prokaryotes |
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