Microscopy and Staining Techniques

Flashcards reviewing key concepts in microscopy and staining methods.

How do you determine total magnification in a microscope?

Multiply the ocular lens magnification by the objective lens magnification.

What is refraction?

The measure of the light-bending ability of a medium.

What is resolution in microscopy?

The ability of the lenses of a microscope to distinguish fine detail and structure.

Which microscope uses an opaque disk to block light, producing a light specimen on a dark background?

Darkfield microscope.

Which microscope uses an ultraviolet light source to produce a brightly colored object against a dark background?

Fluorescence microscope.

Which microscope is useful for studying detailed surface structures of intact cells and viruses?

Scanning electron microscope.

How do most microorganisms appear when viewed unstained with brightfield microscopy?

Colorless.

What is the charge of the chromophore of basic dyes, and how does it relate to bacteria?

Positively charged and attracted to most types of bacteria.

Which of the following is NOT a kind of staining technique: simple, differential, special, or selective?

Selective.

What does fixing a slide accomplish besides attaching microorganisms?

Killing the organisms

What is negative staining?

A technique used for preparing a slide with colorless bacteria against a colored background.

What is the mordant in the Gram stain?

Iodine.

What type of stain is used for capsules?

Negative stain.

What color are gram-negative bacteria at the completion of the gram staining process?

Red/pink.

What is the appearance of Mycobacterium leprae after being stained with an acid-fast stain?

Bright pink.