Question

Assertion : Gramnegative bacteria do not retain the stain when washed with alcohol.
Reason : The outer face of the outer membrane of Gramnegative 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 statements

Answer 1

Answer: (A)

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 :
(a) Gram positive, i.e., those which give (+) ve test with gram stain.
(b) Gram negative, i.e., those which give (-)ve test with gram stain. The steps involved in gram staining are summarised 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.