Microbiology Quiz 2 with correct Answers 2023

The purpose of a mordant in the Gram stain is -to remove the simple stain -to make bacterial cells larger -to only make the flagella visible -to prevent the crystal violet from leaving the cells -none of the above correct answers: to prevent the crystal violet from leaving the cells (increase the affinity of the primary stain) This microscope produces an image of a light cell against a dark background; internal structures are NOT visible. correct answers: darkfield microscope Which of the following is NOT correct? -1 um = 10^-6m -1 nm = 10^-9m -1 um = 10^3nm -1 um = 10^-3mm -1 nm = 10^-6um correct answers:1 nm = 10^-6um The counterstain in the Gram stain is _____________. correct answers: a basic dye The light that hits the specimen is scattered and does not come directly from the light source in this microscope. correct answers: darkfield microscope The appearance of Gram-positive bacteria after addition of the first dye in the Gram stain is ____________. correct answers: purple The appearance of Gram-negative bacteria after addition of the mordant in the Gram stain is _____________. correct answers: purple The appearance of Gram-negative bacteria after addition of the decolorizing agent in the Gram stain is _____________. correct answers: colorless The appearance of Gram-positive bacteria after adding the counterstain in the Gram stain is _______________. correct answers: purple