1. Which of the following is a common Gram-positive bacteria
a) Rhizobium of root nodules
b) Lactobacillus in curd
c) Escherichia coli
d) none of these
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2.Gram staining is an example of
a) Acid fast stain
b) Acid stain
c) Differential stain
d) None of the above
3.Gram staining was developed in
a) 1882
b) 1883
c) 1884
d) 1885
4.Which of the following statements are true regarding Gram positive bacteria
a) cell wall has a thick peptidoglycan layer
b) cell wall lipid content is very low
c) lipopolysaccharide layer is absent
d) all of these
5.Gram staining was developed by
a) French microbiologist Louis Pasteur
b) Dutch lens maker Leeuwenhoek
c) Danish physician Christian Gram
d) Dutch physician Christian Gram
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6.Which of the following statements is incorrect regarding Gram negative bacteria
a) cell wall has a thin peptidoglycan layer
b) cell wall lipid content is very low
c) lipopolysaccharide layer is present
d) all of these
7.In Gram staining, if some bacteria retain the crystal violet stain after alcohol treatment. Then the bacteria is
a) Gram positive
b) Gram negative
c) procedure is incomplete to answer this question
d) none of these
8.Counter stain used in Gram staining is
a) Safranin
b) Crystal violet
c) carbol fuschin
d)acetocarmine
9.In Gram staining, the alcohol acts on
a) Teichoic acids
b) Periplasm
c) Membrane lipids
d) Peptidoglycan
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10.Lipopolysaccharide is found in cell wall of
a) Gram positive bacteria
b) Gram negative bacteria
c) Both
d) Fungi
11.The differential staining property of Gram staining is primarily due to
a) difference in lipid content in Gram positive and Gram-negative bacteria
b) difference in protoplasmic contents in Gram positive and Gram-negative bacteria
c) difference in teichoic acid content in Gram positive and Gram-negative bacteria
d) all of these
12.In Gram staining iodine is used as a
a) fixative
b) mordant
c) solubiulizer
d) stain
13.After ethanol treatment Gram negative bacteria can be visualized
a) only by counter staining with safranin
b) in violet color of crystal violet
c) only by addition of iodine solution
d) none of these
14.During ethanol treatment in gram staining,
a) crystal violet stain is dissolved in alcohol in Garm negative bacteria due to high lipid content in the outer layer
b) crystal violet stain is retained in Garm positive bacteria due to less lipid content and thick peptidoglycan wall
c) both a and b
d) none of these
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15.The most common stains used in Gram staining is
a) crystal violet and methylene blue
b) crystal violet and safranin
c) crystal violet and carbol fuschin
d) safranin and methylene blue