question

1 micrometer

answer

1,000 nanometers is equal to which of the following?

question

differential interference contrast microscopy

answer

The three-dimensional effect observed in this micrograph is produced by ______________.

question

condenser

answer

Which part of the microscope shown here focuses light through the specimen?

question

False

Mycobacterium tuberculosis, the cause of tuberculosis, is often demonstrated by the use of such stains as the acid-fast stain.

answer

A patient suffering from tuberculosis could be diagnosed by the use of a negative stain.

question

endospores

answer

Acid-fast Mycobacteria are distinguished from non-acid fast bacteria by the presence of ____________________.

question

scanning electron microscopy

answer

A three-dimensional image of a bacterium is achieved by using ____________________.

question

10X

answer

Assume that you are looking at a 25 um plant cell magnified 100X. If you are using a 10X ocular lens, what is the magnifying power of the objective lens?

question

True

answer

Bacterial smears must be heat-fixed prior to staining procedures.

question

Condenser

answer

Which part of the microscope shown here focuses light through the specimen?

question

False

answer

A counterstain may be used to improve the bonding between a stain and the specimen.

question

selectively remove stain from cells.

answer

A decolorizer is used to:

question

False.
Mycobacterium tuberculosis, the cause of tuberculosis, is often demonstrated by the use of such stains as the acid-fast stain.

answer

A patient suffering from tuberculosis could be diagnosed by the use of a negative stain.

question

False.
A scanning tunneling microscope is an example of a probe microscope.

answer

A scanning tunneling microscope is an example of a light microscope.

question

scanning electron microscopy.

answer

A three-dimensional image of a bacterium is achieved by using ____________________.

question

the phase plate.

answer

All of the following are components of a bright-field compound microscope EXCEPT:

question

The specimen must be sectioned prior to viewing.

answer

All of the following are true for both TEM and SEM except:

question

Atomic force

answer

All of the following are types of light microscopy except:

question

condenser

answer

As light travels through a compound light microscope, what is the second structure through which it passes?

question

10X

answer

Assume that you are looking at a 25 um plant cell magnified 100X. If you are using a 10X ocular lens, what is the magnifying power of the objective lens?

question

True

answer

Bacterial smears must be heat-fixed prior to staining procedures.

question

True
Heat or chemicals, such as methanol and formalin, are good fixation agents. Both of these types of agents help dry out cells and make them stick to a slide.

answer

Endospore stains and acid-fast stains both involve heat.

question

True

answer

Fluorescent-labeled antibodies would allow specific recognition of one bacterium in a mixed culture of bacteria.

question

True

answer

Gram-positive bacteria retain the primary stain after decolorizing with alcohol.

question

1000X

answer

If you use a compound light microscope, a 2 um (micrometer) bacterial cell is best seen at which magnification?

question

False

answer

Immersion oil acts to decrease refraction of light rays and thus increase magnification.

question

False
Immersion oil works by increasing the numerical aperture of a lens.

answer

Immersion oil improves resolution because it decreases the working distance.

question

False
The condenser lens, not the ocular lens, directs light through the specimen.

answer

In a compound microscope, the lens that directs light through the specimen is the ocular lens.

question

colorless.

answer

In a negative stain, gram-negative bacteria will be:

question

unstained in a colored background.

answer

In a negative staining procedure, the bacterial cells would be ____________________.

question

Answers A, B, and C are correct.

answer

In microscopy, which of the following plays an important role in visualizing extremely small objects clearly?

question

primary stain.

answer

In the Gram stain, crystal violet is the ____________________.

question

in thick layers of peptidoglycan.

answer

In the Gram stain, crystal violet remains in gram-positive cells after treatment with alcohol because crystal violet-iodine (CV-I) complexes are trapped ____________________.

question

purple

answer

In the Gram stain, if the decolorizing step is deleted, gram-negative cells will appear ____at the completion of the staining procedure.

question

counterstain

answer

In the Gram stain, safranin serves as the ___________.

question

ethanol/acetone

answer

In the Gram stain, which of the reagents actually differentiates between Gram-positive and Gram-negative cells?

question

presence of an endospore.

answer

In the Gram-stain procedure, a clear oval in the center of a cell could indicate:

question

clear halos

answer

In the capsule stain using India ink, capsules are distinguished as _________surrounding cells.

question

alcohol

answer

In the decolorizing step of the Gram stain, which reagent is used?

question

False

answer

Magnification is the quality of the microscope that allows one to distinguish between two points that are very close together.

question

False

answer

Phase-contrast microscopy is an especially useful type of microscopy because it permits detailed examination of internal structures in living microorganisms.

question

True

answer

Phase-contrast microscopy is an especially useful type of microscopy because it permits detailed examination of internal structures in living microorganisms.

question

3-1-4-5-2

answer

Place the structures of the compound light microscope in the order that light passes through them on the way to the observer's eyes: (1) condenser, (2) ocular lens, (3) illuminator, (4) specimen, (5) objective lens.

question

wavelength

answer

Resolution is great when using an electron microscope because the _____________ of the electron beam is much less than that of visible light.

question

False

answer

Stains used in electron microscopy increase the contrast between specimen and background by colorizing the internal structures differently.

question

False

answer

The Gram stain is important in microbiology because it differentiates all pathogens from all nonpathogenic bacteria.

question

2000x

answer

The limit of useful magnification for a light microscope is _______________________.

question

make gram-negative cells visible.

answer

The purpose of the counterstain in the Gram stain is to:

question

It attaches cells firmly to the slide's surface.

answer

What is the purpose of fixation in smear preparation?

question

Which is common to the Gram stain and acid-fast stain?

answer

Fixation of the smear prior to staining.

question

UV > Violet > Red

answer

Which of the following has the shortest wavelength?

question

electron microscope

answer

Which of the following is not a modification of a compound microscope?

question

Cell structures are differentiated

answer

Which of the following is not accomplished by fixing cells to a slide?

question

0.02 microm ribosome

answer

Which of the following is not visible through a compound light microscope?

question

1000 nm (length) mitochondrion

answer

Which of the following is the same size as a 1 microm (length) bacterial cell?

question

0.01 cm

answer

Which of the following measurements does not equal 1mm?

question

acid-fast stain

answer

Which of the following stains is used for visualizing Mycobacterium?

question

Probe microscope

Confocal, phase-contrast, and dark-field microscopes are all types of light microscopes. As such, they can magnify only up to about 2,000X.

answer

Which of the following types of microscopes should be used to view a specimen at 50,000X?

question

Phase-contrast

answer

Which of the following types of microscopy is most useful for viewing the internal structures of unstained specimens?

question

Brightfield.

answer

Which type of light microscopy is used to visualize stained specimens?

question

Atomic force

answer

Which type of microscope uses a metal and diamond probe that is gently forced down along the surface of a specimen?

question

Fluorescence microscopy

answer

Which type of microscopy is used to identify pathogenic bacteria in clinical specimens?

question

human cells and gram-positive bacteria.

answer

You prepare a smear of tooth scrapings and see large (~10 microm) red nucleated cells and smaller (~2 microm) blue cells. You can conclude that you are seeing:

question

there are bacteria on your teeth.

answer

You see blue bacterial cells in a gram-stained smear from your tooth scrapings. You can conclude that:

question

he didn't fix the smear.

answer

Your lab partner tells you the bacteria are moving in his Gram stain. You can conclude that:

Microbiology Chapter 4: Microscopy – Flashcards

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