Chapter 03: Observing Microbes
MULTIPLE CHOICE
1. Resolution is
a. the ability to detect individual cells.
b. using a microscope to be seen.
c. increasing the size of an image.
d. the smallest distance two objects can be separated and still be distinguished.
ANS: D DIF: Easy REF: 3.1
OBJ: 3.1a Explain how magnification improves resolution of a microscopic image.
MSC: Remembering
2. Which of the following equals one millimeter?
a. 10-3 m c. 10-9 m
b. 10 m
-6
d. 10-12 m
ANS: A DIF: Easy REF: 3.1
OBJ: 3.1a Explain how magnification improves resolution of a microscopic image.
MSC: Remembering
3. Which of the following statements is INCORRECT?
a. In fluorescence microscopy, fluorescent-labeled cellular structures are identified.
b. In light microscopy, the object appears light against a dark background.
c. In phase-contrast microscopy, organelles appear as light/dark patterns by variation in
refractive indexes.
d. Electron microscopy uses electrons to visualize the specimen.
ANS: B DIF: Moderate REF: 3.1
OBJ: 3.1b Explain what can be learned from different kinds of microscopy.
MSC: Analyzing
4. In a compound microscope, which is the accurate pathway of light?
a. light source, condenser, objective, specimen, eyepiece
b. condenser, light source, eyepiece, specimen, objective
c. eyepiece, objective, specimen, condenser, light source
d. light source, condenser, specimen, objective, eyepiece
ANS: D DIF: Easy REF: 3.3
OBJ: 3.3a Explain the use of a bright-field microscope. MSC: Remembering
5. Which microscope is used to observe specific fluorescent-labeled structures?
a. a compound light microscope c. a fluorescence microscope
b. a phase-contrast microscope d. an electron microscope
ANS: C DIF: Easy REF: 3.1
OBJ: 3.1b Explain what can be learned from different kinds of microscopy.
MSC: Remembering
,6. What is the total magnification of a specimen viewed with a 10x ocular lens and a 35x objective lens?
a. 10x c. 350x
b. 3.5x d. 3,500x
ANS: C DIF: Moderate REF: 3.3
OBJ: 3.3b Describe how to observe an object in focus by using a compound microscope.
MSC: Applying
7. In the figure below, line “B” points to the microscope’s
a. ocular lens. c. condenser.
b. objective. d. light source.
ANS: B DIF: Easy REF: 3.3
OBJ: 3.3b Describe how to observe an object in focus by using a compound microscope.
MSC: Remembering
8. In the figure below, line “C” points to the microscope’s
a. ocular lens. c. condenser.
b. objective. d. light source.
ANS: C DIF: Easy REF: 3.3
OBJ: 3.3b Describe how to observe an object in focus by using a compound microscope.
, MSC: Remembering
9. In the figure below, line “D” points to the microscope’s
a. ocular lens. c. condenser.
b. objective. d. light source.
ANS: D DIF: Easy REF: 3.3
OBJ: 3.3b Describe how to observe an object in focus by using a compound microscope.
MSC: Remembering
10. You are performing a Gram stain to differentiate between Gram-positive and Gram-negative bacteria.
At the end of the procedure, a Gram-positive cell will appear
a. purple. c. pink.
b. colorless. d. blue.
ANS: A DIF: Easy REF: 3.4
OBJ: 3.4b Describe how the Gram stain distinguishes two classes of bacteria.
MSC: Understanding
11. You complete a Gram stain on Gram-positive bacteria; however, you over-decolorize your sample.
What color will your bacteria be at this point?
a. purple c. pink
b. colorless d. blue
ANS: C DIF: Difficult REF: 3.4
OBJ: 3.4b Describe how the Gram stain distinguishes two classes of bacteria.
MSC: Analyzing
12. Which of the following is the correct order of the Gram-stain regents?
a. iodine, crystal violet, safranin, ethanol
b. ethanol, crystal violet, safranin, iodine
c. crystal violet, ethanol, iodine, safranin
d. crystal violet, iodine, ethanol, safranin
ANS: D DIF: Moderate REF: 3.4
OBJ: 3.4b Describe how the Gram stain distinguishes two classes of bacteria.
MSC: Applying
MULTIPLE CHOICE
1. Resolution is
a. the ability to detect individual cells.
b. using a microscope to be seen.
c. increasing the size of an image.
d. the smallest distance two objects can be separated and still be distinguished.
ANS: D DIF: Easy REF: 3.1
OBJ: 3.1a Explain how magnification improves resolution of a microscopic image.
MSC: Remembering
2. Which of the following equals one millimeter?
a. 10-3 m c. 10-9 m
b. 10 m
-6
d. 10-12 m
ANS: A DIF: Easy REF: 3.1
OBJ: 3.1a Explain how magnification improves resolution of a microscopic image.
MSC: Remembering
3. Which of the following statements is INCORRECT?
a. In fluorescence microscopy, fluorescent-labeled cellular structures are identified.
b. In light microscopy, the object appears light against a dark background.
c. In phase-contrast microscopy, organelles appear as light/dark patterns by variation in
refractive indexes.
d. Electron microscopy uses electrons to visualize the specimen.
ANS: B DIF: Moderate REF: 3.1
OBJ: 3.1b Explain what can be learned from different kinds of microscopy.
MSC: Analyzing
4. In a compound microscope, which is the accurate pathway of light?
a. light source, condenser, objective, specimen, eyepiece
b. condenser, light source, eyepiece, specimen, objective
c. eyepiece, objective, specimen, condenser, light source
d. light source, condenser, specimen, objective, eyepiece
ANS: D DIF: Easy REF: 3.3
OBJ: 3.3a Explain the use of a bright-field microscope. MSC: Remembering
5. Which microscope is used to observe specific fluorescent-labeled structures?
a. a compound light microscope c. a fluorescence microscope
b. a phase-contrast microscope d. an electron microscope
ANS: C DIF: Easy REF: 3.1
OBJ: 3.1b Explain what can be learned from different kinds of microscopy.
MSC: Remembering
,6. What is the total magnification of a specimen viewed with a 10x ocular lens and a 35x objective lens?
a. 10x c. 350x
b. 3.5x d. 3,500x
ANS: C DIF: Moderate REF: 3.3
OBJ: 3.3b Describe how to observe an object in focus by using a compound microscope.
MSC: Applying
7. In the figure below, line “B” points to the microscope’s
a. ocular lens. c. condenser.
b. objective. d. light source.
ANS: B DIF: Easy REF: 3.3
OBJ: 3.3b Describe how to observe an object in focus by using a compound microscope.
MSC: Remembering
8. In the figure below, line “C” points to the microscope’s
a. ocular lens. c. condenser.
b. objective. d. light source.
ANS: C DIF: Easy REF: 3.3
OBJ: 3.3b Describe how to observe an object in focus by using a compound microscope.
, MSC: Remembering
9. In the figure below, line “D” points to the microscope’s
a. ocular lens. c. condenser.
b. objective. d. light source.
ANS: D DIF: Easy REF: 3.3
OBJ: 3.3b Describe how to observe an object in focus by using a compound microscope.
MSC: Remembering
10. You are performing a Gram stain to differentiate between Gram-positive and Gram-negative bacteria.
At the end of the procedure, a Gram-positive cell will appear
a. purple. c. pink.
b. colorless. d. blue.
ANS: A DIF: Easy REF: 3.4
OBJ: 3.4b Describe how the Gram stain distinguishes two classes of bacteria.
MSC: Understanding
11. You complete a Gram stain on Gram-positive bacteria; however, you over-decolorize your sample.
What color will your bacteria be at this point?
a. purple c. pink
b. colorless d. blue
ANS: C DIF: Difficult REF: 3.4
OBJ: 3.4b Describe how the Gram stain distinguishes two classes of bacteria.
MSC: Analyzing
12. Which of the following is the correct order of the Gram-stain regents?
a. iodine, crystal violet, safranin, ethanol
b. ethanol, crystal violet, safranin, iodine
c. crystal violet, ethanol, iodine, safranin
d. crystal violet, iodine, ethanol, safranin
ANS: D DIF: Moderate REF: 3.4
OBJ: 3.4b Describe how the Gram stain distinguishes two classes of bacteria.
MSC: Applying
