Chapter 3: Microscopy and Staining
Question Type: Multiple Choice
1) Which of the following statements about Leeuwenhoek’s microscopes is false?
a) Leeuwenhoek kept his technique secret.
b) They magnified objects 100 to 300 times.
c) For each specimen a new microscope had to be made.
d) They were able to reveal very fine details of bacteria.
Answer: d
Difficulty: Medium
Learning Objective 1: LO 3.1 Review the known properties of light, such as wavelength and resolution, and how light travels through various media.
Section Reference 1: Section 3.1 Historical Microscopy
2)Which of the following statements about resolution is true?
a) Resolution refers to the ability of a lens to distinguish adjacent objects.
b) With regard to light, resolution means the same thing as wavelength.
c) Resolution refers to a microscope’s ability to magnify objects.
d) Resolution is equal to the distance between two adjacent crests of a wave.
Answer: a
Difficulty: Hard
Learning Objective 1: LO 3.1 Review the known properties of light, such as wavelength and resolution, and how light travels through various media.
Section Reference 1: Section 3.2 Principles of Microscopy
3) A compound light microscope can generally see objects as no smaller than a _____.
a) ribosome
b) large protozoa
c) small bacterium
d)typical virus
Answer: c
Difficulty: Easy
Learning Objective 1: LO 3.2 Identify the components and purposes of the compound light microscope and electron microscope, providing examples of applications of these types of microscopy.
Section Reference 1: Section 3.3 Light Microscopy
4) Light of ______wavelength typically will result in ______resolution.
a) longer, better
b) shorter, better
c) any, poor
d) shorter, worse
Answer: b
Difficulty: Medium
Learning Objective 1: LO 3.1 Review the known properties of light, such as wavelength and resolution, and how light travels through various media.
Section Reference 1: Section 3.2 Principles of Microscopy
5) The formula for the resolving power (resolution distance) of a lens is /2NA (wavelength /2 x numerical aperture). What does this say about resolving power?
a) The smaller the wavelength, the greater the resolving power of the lens.
b) Resolving power is not related the lens’ numerical aperture.
c) We cannot precisely calculate a lens resolving power.
d) A larger resolving power is indicative of a better lens.
Answer: a
Difficulty: Medium
Learning Objective 1: LO 3.1 Review the known properties of light, such as wavelength and resolution, and how light travels through various media.
Section Reference 1: Section 3.2 Principles of Microscopy
6) When light passes through an object, ______of the light has occurred.
a) reflection
b) absorption
c) transmission
d) fluorescence
Answer: c
Difficulty: Easy
Learning Objective 1: LO 3.1 Review the known properties of light, such as wavelength and resolution, and how light travels through various media.
Section Reference 1: Section 3.2 Principles of Microscopy
7) When light bends as it passes through an object, ______, of the light has occurred.
a) reflection
b) absorption
c) transmission
d) refraction
Answer: d
Difficulty: Easy
Learning Objective 1: LO 3.1 Review the known properties of light, such as wavelength and resolution, and how light travels through various media.
Section Reference 1: Section 3.2 Principles of Microscopy
8) When light rays pass into an object but do not emerge, ______has taken place.
a) reflection
b) absorption
c) refraction
d) transmission
Answer: b
Difficulty: Easy
Learning Objective 1: LO 3.1 Review the known properties of light, such as wavelength and resolution, and how light travels through various media.
Section Reference 1: Section 3.2 Principles of Microscopy
9) In order to make use of light for a microscopic examination of an object the object must ______or ______light.
a) absorb, luminesce
b) transmit, absorb
c) transmit, reflect
d) reflect, absorb
Answer: c
Difficulty: Medium
Learning Objective 1: LO 3.1 Review the known properties of light, such as wavelength and resolution, and how light travels through various media.
Section Reference 1: Section 3.2 Principles of Microscopy
10) Electron microscopes have a much better resolving power when compared to light microscopes because electrons _____.
a) are invisible to the eye
b) have longer wavelengths than visible light rays
c) have shorter wavelengths than visible light rays
d) are negatively charged
Answer: c
Difficulty: Easy
Learning Objective 1: LO 3.2 Identify the components and purposes of the compound light microscope and electron microscope, providing examples of applications of these types of microscopy.
Section Reference 1: Section 3.4 Electron Microscopy
11) Diffraction occurs when light _____.
a) is reflected by an object
b) passes through a small opening
c) changes wavelengths
d) is absorbed by a normally transparent object (like a glass slide)
Answer: b
Difficulty: Medium
Learning Objective 1: LO 3.1 Review the known properties of light, such as wavelength and resolution, and how light travels through various media.
Section Reference 1: Section 3.2 Principles of Microscopy
12) Why is diffraction a problem for microscopy?
a) The lens acts as a large aperture through which light must pass.
b) The small size of higher-power lenses causes severe diffraction.
c) The loss of light results in blurred images.
d) Diffraction of light is useful when using an oil immersion lens to view objects.
Answer: b
Difficulty: Medium
Learning Objective 1: LO 3.1 Review the known properties of light, such as wavelength and resolution, and how light travels through various media.
Section Reference 1: Section 3.2 Principles of Microscopy
13) What is true about the index of refraction?
a) If light rays are taken up by the object than it has a high index of refraction.
b) Refraction measures the frequency of the light as it reflects from a material.
c) Oil immersion lenses increase the problem of refraction.
d) Light will bend as it passes through two substances with different indices of refraction.
Answer: d
Difficulty: Hard
Learning Objective 1: LO 3.1 Review the known properties of light, such as wavelength and resolution, and how light travels through various media.
Section Reference 1: Section 3.2 Principles of Microscopy
14) During microscopic observation of a specimen, the amount of light that is allowed to pass through the specimen is controlled by the:
a) condenser
b) objective lens
c) iris diaphragm
d) ocular lens
Answer: c
Difficulty: Medium
Learning Objective 1: LO 3.2 Identify the components and purposes of the compound light microscope and electron microscope, providing examples of applications of these types of microscopy.
Section Reference 1: Section 3.3 Light Microscopy
15) The lens closest to the slide during a microscopic examination is the _____.
a) ocular
b) objective
c) condenser
d) compound
Answer: b
Difficulty: Easy
Learning Objective 1: LO 3.2 Identify the components and purposes of the compound light microscope and electron microscope, providing examples of applications of these types of microscopy.
Section Reference 1: Section 3.3 Light Microscopy
16) A compound microscope has _____.
a) two eyepieces
b) a total magnification of 5,000X
c) only fine adjustment and no coarse adjustment
d) more than one lens
Answer: d
Difficulty: Easy
Learning Objective 1: LO 3.2 Identify the components and purposes of the compound light microscope and electron microscope, providing examples of applications of these types of microscopy.
Section Reference 1: Section 3.3 Light Microscopy
17) The lens closest to your eyes during a microscopic examination is the _____.
a) ocular
b) objective
c) condenser
d) compound
Answer: a
Difficulty: Easy
Learning Objective 1: LO 3.2 Identify the components and purposes of the compound light microscope and electron microscope, providing examples of applications of these types of microscopy.
Section Reference 1: Section 3.3 Light Microscopy
18) Most light microscopes contain a/an ______that converges the light beam so that it passes through the specimen.
a) objective lens
b) iris diaphragm
c) mechanical stage
d) condenser
Answer: d
Difficulty: Medium
Learning Objective 1: LO 3.2 Identify the components and purposes of the compound light microscope and electron microscope, providing examples of applications of these types of microscopy.
Section Reference 1: Section 3.3 Light Microscopy
19) The total magnification of a specimen being viewed with a 10X ocular lens and a 40X objective lens is _____.
a) 4X
b) 40X
c) 400X
d) 4000X
Answer: c
Difficulty: Easy
Learning Objective 1: LO 3.2 Identify the components and purposes of the compound light microscope and electron microscope, providing examples of applications of these types of microscopy.
Section Reference 1: Section 3.3 Light Microscopy
20) To calculate the total magnification of a light microscope you must know the magnification of the _____ lenses.
a) objective and condenser
b) ocular and condenser
c) objective and condenser
d) objective and ocular
Answer: d
Difficulty: Medium
Learning Objective 1: LO 3.2 Identify the components and purposes of the compound light microscope and electron microscope, providing examples of applications of these types of microscopy.
Section Reference 1: Section 3.3 Light Microscopy
21) A parfocal microscope:
a) has more than one source of illumination
b) has both coarse and fine focusing adjustment
c) accentuates small differences in the refractive index of intracellular structures
d) allows for specimens to remain in focus when changing between magnification
Answer: d
Difficulty: Medium
Learning Objective 1: LO 3.2 Identify the components and purposes of the compound light microscope and electron microscope, providing examples of applications of these types of microscopy.
Section Reference 1: Section 3.3 Light Microscopy
22) A microscope in which light rays pass directly through a specimen is a ______microscope.
a) bright field
b) dark field
c) phase-contrast
d) Nomarski
Answer: a
Difficulty: Medium
Learning Objective 1: LO 3.2 Identify the components and purposes of the compound light microscope and electron microscope, providing examples of applications of these types of microscopy.
Section Reference 1: Section 3.3 Light Microscopy
23) A microscope that converts changes in the speed of light as it passes through an object into differences in brightness is a ______microscope.
a) bright field
b) dark field
c) phase-contrast
d) Nomarski
Answer: c
Difficulty: Medium
Learning Objective 1: LO 3.2 Identify the components and purposes of the compound light microscope and electron microscope, providing examples of applications of these types of microscopy.
Section Reference 1: Section 3.3 Light Microscopy
24) Ultraviolet light is a key component of:
a) bright-field microscopy
b) dark-field microscopy
c) phase-contrast microscopy
d) fluorescence microscopy
Answer: d
Difficulty: Easy
Learning Objective 1: LO 3.2 Identify the components and purposes of the compound light microscope and electron microscope, providing examples of applications of these types of microscopy.
Section Reference 1: Section 3.3 Light Microscopy
25) Which is a false statement about light microscopy?
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 cannot determine whether a foreign organism such as a microbe is present in a specimen.
d) A Nomarski microscope produces much higher resolution than the standard phase-contrast microscope.
Answer: c
Difficulty: Medium
Learning Objective 1: LO 3.2 Identify the components and purposes of the compound light microscope and electron microscope, providing examples of applications of these types of microscopy.
Section Reference 1: Section 3.3 Light Microscopy
26) The advent of the electron microscope allowed ______to be viewed for the first time.
a) protozoa
b) bacteria
c) viruses
d) algae
Answer: c
Difficulty: Easy
Learning Objective 1: LO 3.2 Identify the components and purposes of the compound light microscope and electron microscope, providing examples of applications of these types of microscopy.
Section Reference 1: Section 3.4 Electron Microscopy
27) Electron microscopes use ______to focus the electron beam.
a) glass lenses
b) electromagnets
c) mechanical stages
d) laser beams
Answer: b
Difficulty: Medium
Learning Objective 1: LO 3.2 Identify the components and purposes of the compound light microscope and electron microscope, providing examples of applications of these types of microscopy.
Section Reference 1: Section 3.4 Electron Microscopy
28) The best electron microscopes have a resolution of _____ nm.
a) 0.1
b) 1
c) 10
d) 100
Answer: b
Difficulty: Hard
Learning Objective 1: LO 3.2 Identify the components and purposes of the compound light microscope and electron microscope, providing examples of applications of these types of microscopy.
Section Reference 1: Section 3.4 Electron Microscopy
29) Transmission electron microscopes have a maximum magnification of _____.
a) 1,000X
b) 100,000X
c) 500,000X
d) 1,000,000X
Answer: c
Difficulty: Medium
Learning Objective 1: LO 3.2 Identify the components and purposes of the compound light microscope and electron microscope, providing examples of applications of these types of microscopy.
Section Reference 1: Section 3.4 Electron Microscopy
30) Electron microscopes:
a) that are scanning have better resolution than those that are transmission
b) are much more expensive and take up more space than light microscopes
c) can use the same preparations of specimens that have been prepared for viewing with a light microscope
d) have a resolving power approximately 10 times better than the best light microscope
Answer: b
Difficulty: Easy
Learning Objective 1: LO 3.2 Identify the components and purposes of the compound light microscope and electron microscope, providing examples of applications of these types of microscopy.
Section Reference 1: Section 3.4 Electron Microscopy
31) Three dimensional views of cells and other small object could best be obtained using a:
a) phase contrast microscope
b) dark-field microscope
c) transmission electron microscope (TEM)
d) scanning electron microscope (SEM)
Answer: d
Difficulty: Hard
Learning Objective 1: LO 3.2 Identify the components and purposes of the compound light microscope and electron microscope, providing examples of applications of these types of microscopy.
Section Reference 1: Section 3.4 Electron Microscopy
32) Which of the following can be used to examine live specimens?
a) TEM
b) SEM
c) scanning tunneling electron microscope
d) atomic force microscope
Answer: c
Difficulty: Medium
Learning Objective 1: LO 3.2 Identify the components and purposes of the compound light microscope and electron microscope, providing examples of applications of these types of microscopy.
Section Reference 1: Section 3.4 Electron Microscopy
33) The technique that involves the evaporation of water from a frozen and fractured specimen is called:
a) shadow casting
b) freeze-etching
c) heat fixation
d) freeze-fracturing
Answer: b
Difficulty: Hard
Learning Objective 1: LO 3.2 Identify the components and purposes of the compound light microscope and electron microscope, providing examples of applications of these types of microscopy.
Section Reference 1: Section 3.4 Electron Microscopy
34) Colored photos of electron micrographs:
a) reflect the color of the specimen before it was frozen
b) are false color added on during image preparation
c) reflect the color of the specimen after it was frozen
d) are always in pastel shades
Answer: b
Difficulty: Medium
Learning Objective 1: LO 3.2 Identify the components and purposes of the compound light microscope and electron microscope, providing examples of applications of these types of microscopy.
Section Reference 1: Section 3.4 Electron Microscopy
35) Atomic force microscope:
a) allows 3 dimensional imaging and measurement of structures as small as nucleotides in DNA
b) is not yet capable of measuring small forces
c) involves ultraviolet light exciting molecules so that they release light of a longer wavelength
d) has a special condenser and objective lens
Answer: a
Difficulty: Medium
Learning Objective 1: LO 3.2 Identify the components and purposes of the compound light microscope and electron microscope, providing examples of applications of these types of microscopy.
Section Reference 1: Section 3.4 Electron Microscopy
36) The term “basic dyes” refers to the fact that these dyes are _____.
a) easily prepared
b) positively charged
c) attracted to positively charged cell structures
d) simple in their composition
Answer: b
Difficulty: Medium
Learning Objective 1: LO 3.3 Discuss the techniques and purpose of staining specimens and why differential stains such as the Gram stain, capsule stain, endospore stain, and flagellar stain are used.
Section Reference 1: Section 3.5 Techniques of Light Microscopy
37) Which of the following statements about preparing a light microscope specimen is false?
a) Organisms must be heat fixed before viewed in a hanging drop slide.
b) Smears are loopfuls of medium spread on the surface of a glass slide.
c) Wet mounts preparations give good views of microbial mobility.
d) The depth of a smear affects the results;if too thin you may find no organisms.
Answer: a
Difficulty: Easy
Learning Objective 1: LO 3.3 Discuss the techniques and purpose of staining specimens and why differential stains such as the Gram stain, capsule stain, endospore stain, and flagellar stain are used.
Section Reference 1: Section 3.5 Techniques of Light Microscopy
38) A simple stain:
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.
Answer: a
Difficulty: Easy
Learning Objective 1: LO 3.3 Discuss the techniques and purpose of staining specimens and why differential stains such as the Gram stain, capsule stain, endospore stain, and flagellar stain are used.
Section Reference 1: Section 3.5 Techniques of Light Microscopy
39) Which of the following is not a differential stain?
a) Gram stain
b) Schaeffer-Fulton
c) acid-fast stain
d) flagellar stain
Answer: d
Difficulty: Medium
Learning Objective 1: LO 3.3 Discuss the techniques and purpose of staining specimens and why differential stains such as the Gram stain, capsule stain, endospore stain, and flagellar stain are used.
Section Reference 1: Section 3.5 Techniques of Light Microscopy
40) In a Gram stain, the mordant is _____.
a) crystal violet
b) iodine
c) water
d) alcohol
Answer: b
Difficulty: Medium
Learning Objective 1: LO 3.3 Discuss the techniques and purpose of staining specimens and why differential stains such as the Gram stain, capsule stain, endospore stain, and flagellar stain are used.
Section Reference 1: Section 3.5 Techniques of Light Microscopy
41) In a properly executed Gram stain, Gram positive organisms appear ______while Gram negative organisms appear ______.
a) pink, clear
b) pink, purple
c) purple, pink
d) purple, blue
Answer: c
Difficulty: Easy
Learning Objective 1: LO 3.3 Discuss the techniques and purpose of staining specimens and why differential stains such as the Gram stain, capsule stain, endospore stain, and flagellar stain are used.
Section Reference 1: Section 3.5 Techniques of Light Microscopy
42) Why do basic dyes attach to most bacterial surfaces?
a) Most bacterial surfaces are negatively charged.
b) Bacterial cells take up safranin.
c) Most bacterial surfaces resist taking up the stain.
d) Most bacterial surfaces do not have a charge.
Answer: a
Difficulty: Medium
Learning Objective 1: LO 3.3 Discuss the techniques and purpose of staining specimens and why differential stains such as the Gram stain, capsule stain, endospore stain, and flagellar stain are used.
Section Reference 1: Section 3.5 Techniques of Light Microscopy
43) If the step involving iodine were left out of a Gram stain, which of the following would best describe the results?