Question 1

What happens to an electron when excited by light at the excitation wavelength?

Accepted Answer

A)  It remains in the same orbital. 
B)  It moves to a lower energy orbital. 
C)  It moves to a higher energy orbital. 
D)  It emits a photon. 
E)  It is filtered. 
A)  It remains in the same orbital. 
B)  It moves to a lower energy orbital. 
C)  It moves to a higher energy orbital. 
D)  It emits a photon. 
E)  It is filtered.

Question 2

List and briefly describe four ways that light interacts with objects.

Accepted Answer

(1) Absorption: light energy is absorbed

Question 3

Which of the following would be MOST appropriate to visualize viral particles being assembled inside an infected bacterial cell?

Accepted Answer

A)  dark-field microscopy 
B)  atomic force microscopy 
C)  fluorescence microscopy 
D)  scanning electron microscopy 
E)  transmission electron microscopy 
A)  dark-field microscopy 
B)  atomic force microscopy 
C)  fluorescence microscopy 
D)  scanning electron microscopy 
E)  transmission electron microscopy

Question 4

Chlamydia trachomatis transmits infection to a new cell via

Accepted Answer

A)  a membrane vesicle. 
B)  elementary bodies. 
C)  amoeba. 
D)  host membranes. 
E)  the human cell. 
A)  a membrane vesicle. 
B)  elementary bodies. 
C)  amoeba. 
D)  host membranes. 
E)  the human cell.

Question 5

What is the best explanation for a Gram-negative bacterium appearing purple after performing a Gram stain?

Accepted Answer

A)  The safranin was not applied. 
B)  The decolorizer was not applied. 
C)  The iodine was not applied. 
D)  The crystal violet was not applied. 
E)  The stain was properly performed. 
A)  The safranin was not applied. 
B)  The decolorizer was not applied. 
C)  The iodine was not applied. 
D)  The crystal violet was not applied. 
E)  The stain was properly performed.

Question 6

Which type of microscopy is particularly useful to study the surfaces of live bacteria?

Accepted Answer

A)  atomic force 
B)  scanning electron 
C)  transmission electron 
D)  dark-field 
E)  bright-field 
A)  atomic force 
B)  scanning electron 
C)  transmission electron 
D)  dark-field 
E)  bright-field

Question 7

The part of the human eye that is MOST involved in resolving an image is the

Accepted Answer

A)  iris. 
B)  lens. 
C)  optic nerve. 
D)  retina. 
E)  cornea. 
A)  iris. 
B)  lens. 
C)  optic nerve. 
D)  retina. 
E)  cornea.

Question 8

Which two components of the Gram stain form a complex that is retained by Gram-positive cells?

Accepted Answer

A)  crystal violet and iodine 
B)  safranin and iodine 
C)  crystal violet and safranin 
D)  alcohol and safranin 
E)  alcohol and iodine 
A)  crystal violet and iodine 
B)  safranin and iodine 
C)  crystal violet and safranin 
D)  alcohol and safranin 
E)  alcohol and iodine

Question 9

Which of these techniques would provide the best resolution of an enzyme's structure?

Accepted Answer

A)  scanning electron microscopy 
B)  transmission electron microscopy 
C)  cryo-EM 
D)  X-ray diffraction analysis 
E)  atomic force microscopy 
A)  scanning electron microscopy 
B)  transmission electron microscopy 
C)  cryo-EM 
D)  X-ray diffraction analysis 
E)  atomic force microscopy

Question 10

What would happen if a lens had the same refractive index as air?

Accepted Answer

A)  Light would not pass through the lens. 
B)  The image would be magnified more than with a glass lens. 
C)  The image would be magnified, but the resolution would be less than with a glass lens. 
D)  The image would be magnified, and the resolution would be greater than with a glass lens. 
E)  The image would not be magnified. 
A)  Light would not pass through the lens. 
B)  The image would be magnified more than with a glass lens. 
C)  The image would be magnified, but the resolution would be less than with a glass lens. 
D)  The image would be magnified, and the resolution would be greater than with a glass lens. 
E)  The image would not be magnified.

Question 11

A(n) ________ acts to vary the diameter of the light column in a light microscope.

Accepted Answer

A)  condenser 
B)  objective 
C)  ocular 
D)  diaphragm 
E)  lens 
A)  condenser 
B)  objective 
C)  ocular 
D)  diaphragm 
E)  lens

Question 12

Describe three methods of sample preparation for electron microscopy. Which method would cause the fewest artifacts? Why?

Accepted Answer

(1) Samples can be embedded in a polymer

Question 13

What color are Gram-positive and Gram-negative cells when properly Gram stained? For each step of the Gram-stain procedure, predict the colors of a Gram-positive or Gram-negative cell if that step were omitted during staining. Explain your reasoning.

Accepted Answer

Properly Gram stained Gram-positive cell

Question 14

Which of the following methods is used to generate the structure shown below?

Accepted Answer

A)  scanning probe microscopy 
B)  scanning electron microscopy 
C)  transmission electron microscopy 
D)  confocal microscopy 
E)  X-ray crystallography 
A)  scanning probe microscopy 
B)  scanning electron microscopy 
C)  transmission electron microscopy 
D)  confocal microscopy 
E)  X-ray crystallography

Question 15

Resolution is the smallest distance by which two objects can be ________ and still be ________.

Accepted Answer

A)  magnified; seen 
B)  separated; distinguished 
C)  magnified; separated 
D)  distinguished; separated 
E)  magnified; distinguished 
A)  magnified; seen 
B)  separated; distinguished 
C)  magnified; separated 
D)  distinguished; separated 
E)  magnified; distinguished

Question 16

Which type of microscopy gives a "false 3-D image"?

Accepted Answer

A)  Gram stain 
B)  nuclear magnetic resonance 
C)  scanning electron 
D)  negative stain 
E)  differential interference contrast 
A)  Gram stain 
B)  nuclear magnetic resonance 
C)  scanning electron 
D)  negative stain 
E)  differential interference contrast

Question 17

Why are stains used in microscopy? Compare and contrast the stains used in light versus electron microscopy.

Accepted Answer

Stains are used to increase the contrast

Question 18

Transmission electron microscopy commonly has a resolution of ________ the highest resolution possible for light microscopy.

Accepted Answer

A)  10X 
B)  100X 
C)  1,000X 
D)  10,000X 
E)  1,000,000X 
A)  10X 
B)  100X 
C)  1,000X 
D)  10,000X 
E)  1,000,000X

Question 19

List three different differential stains used in microbiology. What can be detected with each?

Accepted Answer

The most common differential stain is th

Question 20

Label the condenser in the figure below.

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
E)  E 
A)  A 
B)  B 
C)  C 
D)  D 
E)  E

Exam 2: Observing the Microbial Cell

What happens to an electron when excited by light at the excitation wavelength?

List and briefly describe four ways that light interacts with objects.

Which of the following would be MOST appropriate to visualize viral particles being assembled inside an infected bacterial cell?

Chlamydia trachomatis transmits infection to a new cell via

What is the best explanation for a Gram-negative bacterium appearing purple after performing a Gram stain?

Which type of microscopy is particularly useful to study the surfaces of live bacteria?

The part of the human eye that is MOST involved in resolving an image is the

Which two components of the Gram stain form a complex that is retained by Gram-positive cells?

Which of these techniques would provide the best resolution of an enzyme's structure?

What would happen if a lens had the same refractive index as air?

A(n) ________ acts to vary the diameter of the light column in a light microscope.

Describe three methods of sample preparation for electron microscopy. Which method would cause the fewest artifacts? Why?

What color are Gram-positive and Gram-negative cells when properly Gram stained? For each step of the Gram-stain procedure, predict the colors of a Gram-positive or Gram-negative cell if that step were omitted during staining. Explain your reasoning.

Which of the following methods is used to generate the structure shown below?

Resolution is the smallest distance by which two objects can be ________ and still be ________.

Which type of microscopy gives a "false 3-D image"?

Why are stains used in microscopy? Compare and contrast the stains used in light versus electron microscopy.

Transmission electron microscopy commonly has a resolution of ________ the highest resolution possible for light microscopy.

List three different differential stains used in microbiology. What can be detected with each?

Label the condenser in the figure below.

Microbial Life: Origin and Discovery

Cell Structure and Function

Bacterial Culture, Growth, and Development

Environmental Influences and Control of Microbial Growth

Viruses

Genomes and Chromosomes

Transcription, Translation, and Bioinformatics

Gene Transfer, Mutations, and Genome Evolution

Molecular Regulation

Viral Molecular Biology

Biotechniques and Synthetic Biology

Energetics and Catabolism

Electron Flow in Organotrophy, Lithotrophy, and Phototrophy

Biosynthesis

Food and Industrial Microbiology

Origins and Evolution

Bacterial Diversity

Archaeal Diversity

Eukaryotic Diversity

Microbial Ecology

Microbes in Global Elemental Cycles

Human Microbiota and Innate Immunity

The Adaptive Immune Response

Microbial Pathogenesis

Microbial Diseases

Antimicrobial Therapy

Clinical Microbiology and Epidemiology

Filters

Resolution is the smallest distance by which two objects can be and still be .