Direction for: In each of the following questions a statement of Assertion is given followed by a corresponding statement of Reason just below it. Of the statements mark the correct answer as
Assertion: Gram-negative bacteria do not retain the stain when washed with alcohol. Reason: The outer face of the outer membrane of Gram-negative bacteria contains lipopolysaccharides, a part of which is integrated into the membrane lipids.A) If both assertion and reason are true and the reason is the correct explanation of the assertion.
B) If both assertion and reason are true but the reason is not the correct explanation of the assertion.
C) If assertion is true statement but reason is false.
D) If both assertion and reason are false.
Correct Answer: A
Solution :
Gram staining technique was developed by the Danish Bacteriologist Hans Christian Gram in 1884. It is a very useful procedure and on the basis of it bacteria can be classified into: Gram positive, i.e., those which give (+) ve test with gram stain. Gram negative, i.e., those which give (-)ve test with gram stain. The steps involved in gram staining are summarized as: The composition of bacterial cell wall is the basis for gram staining technique. The cell wall of gram (-)ve bacteria contain alcohol soluble lipids (lipopolysaccharides) while the cell wall of gram (+)ve bacteria lacks these lipids, therefore, retains the crystal violet?Iodine complex used.
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