Exam 2: The Study of Microbial Structure: Microscopy and Specimen Preparation

Immersion oil can be used to increase the resolution achieved with some microscope lenses because it increases the __________ between the specimen and the objective lens.

The Schaeffer-Fulton procedure is used to stain

Thin films of bacteria that have been air-dried onto a glass microscope slide are called __________.

Scanning electron microscopy is most often used to reveal

Basic dyes such as methylene blue bind to cellular molecules that are

A substage condenser is used to focus light onto the specimen, which increases the resolution of a light microscope.

__________ breaks frozen specimens along lines of greatest weakness, often down the middle of lipid bilayer membranes so that they may be observed by transmission electron microscopy.

The Gram-staining procedure is an example of:

The instrument that produces a bright image of the specimen against a dark background is called a (n) __________ microscope.

__________ is the process by which internal and external structures of cells and organisms are preserved and maintained in position.

Immersion oil increases the amount of light passing through a specimen and entering the objective lens.

If the decolorizer is not left on long enough in the Gram-staining procedure, gram-positive organisms will be stained __________ and gram-negative organisms will be stained __________.

Light rays are refracted (bent) when they cross the interface between materials with different refractive indices.

Resolution decreases when the wavelength of the illuminating light decreases.

The _________________ microscope is capable of atomic resolution of specimens, even when they are immersed in water.

Regions of a specimen with higher electron density scatter ___________ electrons and, therefore, appear __________ in the image projected onto the screen of a transmission electron microscope.

Immersion oil is used to prevent a specimen from drying out.

The Gram-staining procedure is widely used because it allows rapid identification of a microorganism with little additional testing.

Scanning electron microscopes bombard specimens with a stream of electrons; however, the specimen image is produce by electrons that are derived from atoms of the specimen itself rather than by the electrons used to bombard the specimen.

Small internal cell structures are best visualized with a