Microbiology Ch. 3/4

Which microscope is used to see detail of a 300-nm virus?

• Electron microscope

• Fluorescence microscope

• DIC microscope

• Phase-contrast microscope

• Darkfield microscope

Bacterial smears are fixed before staining to

• Kill the bacteria.

• Affix the cells to the slide.

• Make their walls permeable.

• Kill the bacteria and Affix the cells to the slide.

• Accept stain.

The counterstain in the acid-fast stain is

• A negative stain.

• A basic dye.

• A mordant.

• Necessary to determine acid-fast cells.

• An acid dye.

The signal molecule produced in quorum sensing is

• Light.

• An inducer.

• An endospore.

• A counterstain.

• A simple stain.

The appearance of gram-negative bacteria after addition of the mordant in the Gram stain.

• Brown

• Colorless

• Purple

• Red

Which of the following pairs is mismatched?

• Safranin - acid dye

• Iodine - mordant

• Alcohol-acetone - decolorizer

• Crystal violet - basic dye

• Carbolfuchsin - basic dye

Which microscope takes advantage of differences in the refractive indexes of cell structures?

• Fluorescence microscope

• Darkfield microscope

• Electron microscope

• Compound light microscope

• Phase-contrast microscope

Which microscope is most useful for visualizing a biofilm?

• Transmission electron microscope

• Compound light microscope

• Phase-contrast microscope

• Atomic force microscope

• Scanning acoustic microscope

What structure does light pass through after leaving the condenser in a compound light microscope?

• Ocular lens

• Illuminator

• Specimen

• Objective lens

The best use of a negative stain is

• To see endospores.

• To determine cell shape.

• To determine cell size and To determine cell shape

• To determine cell size.

• To determine Gram reaction.