Question 1

Why does immersion oil improve resolution?

Accepted Answer

A)  It increases the angle of refraction of the light. 
B)  It allows light to travel at a uniform speed on its way to the lens. 
C)  It decreases the working distance. 
D)  It increases the numerical aperture. 
E)  It increases numerical aperture and maintains a uniform light speed.

Question 2

Which of the following are magnifying lenses?

Accepted Answer

A)  dark-field stops 
B)  objectives 
C)  oculars 
D)  condensers 
E)  both objectives and the oculars

Question 3

Compare and contrast the three domains identified by Woese: Eukarya, Bacteria, and Archaea.

Accepted Answer

The answer of Compare and contrast the three domains identified...

Question 4

The endospore stain reveals internal structures within cells of the genera Bacillus and Clostridium.

Accepted Answer

A) True 
 B)False

Question 5

Tannic acid is a mordant (chemical fixative) used in the stain.

Accepted Answer

A)  acid-fast 
B)  flagellar 
C)  endospore 
D)  negative 
E)  electron microscopy

Question 6

A (bright-field/confocal/phase-contrast) light microscope can be used to generate three-dimensional images.

Accepted Answer

The answer of A (bright-field/confocal/phase-contrast) light microscope can be used...

Question 7

The total magnification using a 10 ocular and a 100 objective would be (110/1000/10000) X.

Accepted Answer

The answer of The total magnification using a 10 ocular...

Question 8

High resolution images of the internal structures of microbial cells are obtained using microscopes.

Accepted Answer

A)  atomic force 
B)  confocal 
C)  transmission electron 
D)  scanning tunneling 
E)  scanning electron

Question 9

Unstained cells that lack pigment are best observed on the microscope.

Accepted Answer

A)  scanning electron 
B)  bright-field 
C)  scanning tunneling 
D)  phase-contrast 
E)  transmission electron

Question 10

One-thousandth of a meter is a

Accepted Answer

A)  micrometer (μm). 
B)  yard. 
C)  millimeter (mm). 
D)  centimeter (cm). 
E)  nanometer (nm).

Question 11

The light path illustrated in the figure represents a microscope.

Accepted Answer

A)  phase contrast 
B)  dark-field 
C)  bright-field 
D)  fluorescence 
E)  differential interference contrast

Question 12

A sample from a patient is prepared using the Gomori methenamine silver stain. What type of microbe is suspected of being present?

Accepted Answer

A)  bacteria 
B)  parasitic worm larva 
C)  virus 
D)  protozoal parasite 
E)  fungus

Question 13

In the Gram stain procedure, iodine serves as a

Accepted Answer

A)  fixative. 
B)  mordant. 
C)  decolorizing agent. 
D)  counterstain. 
E)  primary stain.

Question 14

Heat is used to drive the stain into cells in the staining procedure(s).

Accepted Answer

A)  endospore stain 
B)  capsule stain 
C)  Gram stain 
D)  acid-fast stain 
E)  both acid-fast and endospore stains

Question 15

Which of the following phenomena produces magnification?

Accepted Answer

A)  the thickness of a microscopic specimen 
B)  the refraction of radiation as it passes through a lens 
C)  the numerical aperture of a lens 
D)  the length of an objective lens 
E)  the wavelength of a radiation source

Question 16

Figure 4-4 represents a (dichotomous/taxonomic/question) key of the type used to identify a microbe.

Accepted Answer

The answer of  Figure 4-4 represents a (dichotomous/taxonomic/question) key...

Question 17

The acid-fast stain is used to stain

Accepted Answer

A)  bacteria with waxy cell walls. 
B)  endospores. 
C)  bacteria lacking cell walls. 
D)  living bacteria. 
E)  bacteria with capsules.

Question 18

You are a scientist studying the highly specific interactions of bacteriophages with their host cells when they first encounter the cell. Discuss what microscope(s) and preparation procedures you might use for this study.

Accepted Answer

The answer of You are a scientist studying the highly...

Question 19

The light source in a microscope is ultraviolet (UV) light.

Accepted Answer

A)  fluorescent 
B)  phase-contrast 
C)  Nomarski 
D)  bright-field 
E)  dark-field

Question 20

Which of the following microscopes produces the highest resolution images?

Accepted Answer

A)  differential interference 
B)  fluorescent 
C)  dark-field 
D)  scanning electron 
E)  atomic force

Exam 4: Microscopy, Staining, and Classification