Question 1

The stains used in the Ziehl-Neelsen acid-fast stain are

Accepted Answer

A)   crystal violet and eosin
B)   carbolfuschin and methylene blue
C)   carbolfuschin and safranin
D)   safranin and methylene blue B

Question 2

Electron microscopes have a much better resolving power when compared to light microscopes because

Accepted Answer

A)   electrons are invisible to the eye
B)   electrons have longer wavelengths than visible light rays
C)   electrons have shorter wavelengths than visible light rays
D)   electrons are negatively charged C

Question 3

A microscope that converts changes in the speed of light as it passes through an object into differences in brightness is a ________ microscope.

Accepted Answer

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

Question 4

A simple stain

Accepted Answer

A)   uses only a single dye
B)   requires only one step to stain a slide
C)   distinguishes between two different parts of an organism
D)   is composed of an equal balance of acid and basic dyes

Question 5

What is the Wright stain? What does it distinguish?

Accepted Answer

The answer of What is the Wright stain? What does...

Question 6

In a Gram stain,the mordant is

Accepted Answer

A)   crystal violet
B)   iodine
C)   water
D)   alcohol

Question 7

Which is a false statement about light microscopy?

Accepted Answer

A)   a dark-field microscope produces bright images against a dark background
B)   a phase contrast microscope gives 3 dimensional images
C)   fluorescent antibody staining can not determine whether a foreign substance such as a microbe is present in a specimen
D)   a Nomarski microscope produces much higher resolution than the standard phase-contrasting microscope

Question 8

When light bends as it passes through an object,________ of the light has occurred.

Accepted Answer

A)   reflection
B)   absorption
C)   transmission
D)   refraction

Question 9

Would light of a higher or lower wavelength give you better resolution when using a microscope? Why? Would a light microscope that had a total magnification of 500X give you better resolution than one that has a magnification of 100X? Why?

Accepted Answer

The answer of Would light of a higher or lower...

Question 10

When light rays pass into an object but do not emerge,________ has taken place.

Accepted Answer

A)   reflection
B)   absorption
C)   refraction
D)   transmission

Question 11

Which of the following can be used to examine live specimens?

Accepted Answer

A)   transmission electron microscope
B)   scanning electron microscope
C)   scanning tunneling electron microscope
D)   atomic force microscope

Question 12

Compare and contrast light microscopy to electron microscopy. Be sure to include how they work and what they can see (or the extent of their total magnification).

Accepted Answer

The answer of Compare and contrast light microscopy to electron...

Question 13

The lens closest to your eyes during a microscopic examination is the

Accepted Answer

A)   ocular
B)   objective
C)   condenser
D)   compound

Question 14

Electron microscopes use ________ to focus the electron beam.

Accepted Answer

A)   glass lenses
B)   electromagnets
C)   mechanical stages
D)   laser beams

Question 15

The total magnification of a specimen being viewed with a 10X ocular lens and a 40X objective lens is

Accepted Answer

A)   4X
B)   40X
C)   400X
D)   4000X

Question 16

Diffraction occurs when

Accepted Answer

A)   light is reflected by an object
B)   light passes through a small opening
C)   light changes wavelengths
D)   light is absorbed by a normally transparent object (like a glass slide)

Question 17

To calculate the total magnification of a light microscope you must know

Accepted Answer

A)   the magnification of the objective and condenser lenses
B)   the magnification of the ocular and condenser lenses
C)   the magnification of objective, ocular and condenser lenses
D)   the magnification of the objective and ocular lenses

Question 18

Ultraviolet light is a key component of

Accepted Answer

A)   bright-field microscopy
B)   dark-field microscopy
C)   phase-contrast microscopy
D)   fluorescence microscopy

Question 19

Why is diffraction a problem for microscopy?

Accepted Answer

A)   because the lens acts as a large aperture through which light must pass
B)   the small size of higher-power lenses causes severe diffraction
C)   loss of light results in blurred images
D)   diffraction of light is useful when using an oil immersion lens to view objects

Question 20

Which of the following statements about preparing a specimen is false?

Accepted Answer

A)   organisms must be heat fixed before viewed in a hanging drop slide
B)   smears are loopful of medium spread on the surface of a glass slide
C)   wet mount preparations give good views of microbial mobility
D)   the depth of a smear affects the results as too thin you may find no organisms

Exam 3: Microscopy and Staining