Chapter 3 Practice ?

What is the function of the diaphragm on a compound microscope?

Controls the amount of light entering the condenser.

What is the ocular lens used for?

To magnify the image formed by the objective lens.

What measures the light-bending ability of a medium?

Refractive index.

By what factor do most ocular lenses magnify specimens?

10x.

What is the ability of the lenses of a microscope to distinguish fine detail called?

Resolution.

Which microscope uses an opaque disk to block light?

Darkfield microscope.

Which microscope utilizes an ultraviolet light source?

Fluorescence microscope.

What microscope forms an image from two sets of light rays?

Phase-contrast microscope.

What microscope uses a metal-and-diamond probe for imaging?

Atomic force microscope.

Which microscope is best for studying surface structures of cells?

Scanning electron microscope.

Where is the specimen placed in transmission electron microscopy?

Copper mesh grid.

Which microscope is valuable for examining different layers of specimens?

Scanning electron microscope.

What is the typical magnification range for scanning electron microscopes?

10,000 to 100,000x.

What is the typical magnification range for transmission electron microscopes?

10,000 to 10,000,000x.

Before staining, most microorganisms appear ________ in brightfield microscopy.

Colorless.

The chromophore of basic dyes is a ________ and is ________ to most bacteria.

Cation; attracted.

Which one of the following is NOT a kind of staining technique?

Selective stain.

Fixing a slide attaches microorganisms while simultaneously:

Killing the organisms.

What technique prepares a slide with colorless bacteria against a colored background?

Negative staining.

What is the mordant in the Gram stain?

Iodine.

Flagella are stained with:

Carbolfuchsin.

Capsules are stained using a(n):

Negative stain.

Endospores are stained using a(n):

Schaeffer-Fulton stain.

What color are gram-negative bacteria after the Gram staining process?

Pink. (-)

How does Mycobacterium leprae appear after acid-fast staining?

Pink.

What is the primary purpose of the Gram stain?

Differentiate bacteria based on cell wall structure.