E-PolyLearning

41. The dye eosinate of methylene blue belongs to which group?
a. Acidic dye
b. Basic dye
c. Neutral dye
d. Oxazine dye
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Answer: (c).Neutral dye

42. What is the correct order of staining reagents in Gram-Staining?
a. Crystal violet, alcohol, iodine solution, safranin
b. Crystal violet, iodine solution, alcohol, safranin
c. Crystal violet, safranin, alcohol, iodine solution
d. Iodine solution, crystal violet, alcohol, safranin
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Answer: (b).Crystal violet, iodine solution, alcohol, safranin

43. Which bacteria appears purple-violet colour after staining?
a. Gram-positive
b. Gram-negative
c. Both Gram-positive and Gram-negative
d. Neither Gram-positive nor Gram-negative
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Answer: (a).Gram-positive

44. Which of the following are true for Gram-negative bacteria?
a. upon alcohol treatment, the permeability of the cell wall increases
b. crystal violet-iodine (CV-I) complex is extracted
c. pore size decreases and the CV-I complex cannot be extracted
d. alcohol treatment increases the permeability of the cell wall and the CV-I complex can be extracted
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Answer: (d).alcohol treatment increases the permeability of the cell wall and the CV-I complex can be extracted

45. Gram-positive bacteria are usually more susceptible to?
a. streptomycin
b. tetracyclin
c. penicillin
d. ampicillin
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Answer: (c).penicillin