False
Viruses are generally measured in
nanometers.
Coating a specimen with a heavy metal is a step in preparing it for (phase/fluorescent/electron) microscopy.
Electron
The process of immobilizing organisms on a glass slide through the application of either heat or chemicals is (staining/mordant/fixation).
Fixation
The total magnification using a 10 ocular and a 100 objective would be (110/1000/10000) X. (Be sure your answer is a numeral.)
1000
Why does immersion oil improve resolution?
It increases numerical aperture and maintains a uniform light speed.
How are negative stains different from other types of stains?
They stain the background, leaving the cells colorless.
Which of the following is an example of a dye used in a simple stain?
Methylene blue
How does the malachite green stain enter an endospore?
It is heated
Following an endospore stain, how does one distinguish endospores from vegetative cells?
What is the fundamental purpose of staining in light microscopy?
To increase the contrast and visibility of the specimen
Why is a specimen smaller than 200 nm not visible with a light microscope?
Anything smaller than 200 nm cannot interact with visible light.
What happens to the light rays when they hit the specimen?
They are reflected, refracted, or absorbed by the specimen.
They are reflected, refracted, or absorbed by the specimen.
What is the role of the ocular lens?
To recreate the image in the viewer’s eye
What is meant by light rays being divergent?
It is spreading out
In a typical brightfield microscope (seen in the animation), at which point does magnification begin?
The objective lens
You are shown a micrograph from a light microscope in which the specimens appear bright compared to the background. The micrograph is probably from a(n) ________ microscope.
dark-field
Which of the following is an incorrect pairing?
numerical aperture; curved glass
In Gram staining, ethanol-acetone is used as a
decolorizing agent
The microscope preferred for viewing living specimens is the ________ microscope.
phase-contrast
Which of the following microscopes produces the highest resolution images?
atomic force
A primary purpose for the use of stains in microscopy is the increase the (magnification/brightness/contrast) of a specimen.
contrast
If a microbiology lab student left the safranin out of the Gram stain procedure, what would be the result?
Gram-positive cells would be purple and Gram-negative cells would be colorless.
The Gram stain can be used to distinguish bacteria based on the structure of their cell walls.
true
In the Gram stain procedure, iodine serves as a
In a compound microscope, the lens that directs light through the specimen is the (ocular/condenser/objective) lens.
condenser
A measurement of a microbe is reported as 1 × 10-6 m, also known as
micrometers (μm).
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