BIOL 271 Microbiology w/ Lab Module 3 Exam Review
Comprehensive Multiple-Choice Question Bank (150 Questions)
SECTION 1: MICROSCOPY FUNDAMENTALS & MEASUREMENT
🟢 1. A nanometer is defined as which of the following?
A) 10⁻³ meters
B) 10⁻⁶ meters
🟢 C) 10⁻⁹ meters
D) 10⁻¹² meters
🔴 Correct Answer: C – A nanometer is one-billionth of a meter (10⁻⁹ m). A micrometer is 10⁻⁶
m, and a millimeter is 10⁻³ m.
🟢 2. A micrometer is defined as:
A) 10⁻³ meters
🟢 B) 10⁻⁶ meters
C) 10⁻⁹ meters
D) 10⁻¹² meters
🔴 Correct Answer: B – A micrometer (μm) is one-millionth of a meter (10⁻⁶ m), commonly
used to measure the size of cells.
🟢 3. True or False: A nanometer is longer than a micrometer.
🟢 A) True
B) False
🔴 Correct Answer: B (False) – A nanometer is 1,000 times smaller than a micrometer.
Specifically, 1 μm = 1,000 nm.
🟢 4. Which unit of measurement is most appropriate for measuring the size of a typical
bacterial cell?
A) Nanometer
🟢 B) Micrometer
C) Millimeter
D) Centimeter
🔴 Correct Answer: B – Bacterial cells are typically measured in micrometers (μm), with most
ranging from 0.5 to 5.0 μm in diameter.
🟢 5. Which unit of measurement is most appropriate for measuring viruses and cellular
organelles?
,🟢 A) Nanometer
B) Micrometer
C) Millimeter
D) Centimeter
🔴 Correct Answer: A – Nanometers (nm) are used to measure viruses, cellular organelles, and
macromolecules. A typical virus ranges from 20–300 nm.
🟢 6. A bacterium has a diameter of 0.5 μm. What is this measurement in nanometers?
A) 5 nm
B) 50 nm
🟢 C) 500 nm
D) 5,000 nm
🔴 Correct Answer: C – 1 μm = 1,000 nm, so 0.5 μm × 1,000 = 500 nm.
🟢 7. The unaided human eye can reliably resolve objects approximately larger than:
A) 1 μm
B) 10 μm
C) 50 μm
🟢 D) 100 μm
🔴 Correct Answer: D – The unaided eye can, on average, clearly resolve objects greater than
100 μm (0.1 mm).
🟢 8. Which of the following could NOT be seen clearly by the unaided eye? Select all that
apply.
A) Protozoa with diameter of 150 μm
🟢 B) Bacteria with diameter of 24 μm
C) Skin cell with diameter of 1,500 μm
🟢 D) Virus with diameter of 0.2 μm
🔴 Correct Answer: B and D – The unaided eye can resolve objects > 100 μm. Bacteria (24 μm)
and viruses (0.2 μm) fall below this threshold and require microscopy.
🟢 9. Resolution is best defined as:
A) The ability to make an image appear larger
🟢 B) The ability to distinguish two adjacent points as separate entities
C) The difference in light intensity between the specimen and background
D) The ability to add color to a specimen
🔴 Correct Answer: B – Resolution refers to the distance between two objects at which they
can still be seen as separate. Poor resolution causes two or more objects to appear as one.
🟢 10. Contrast is best defined as:
,A) The ability to distinguish two adjacent points as separate
🟢 B) The difference in light absorbance between two objects
C) The total magnification of an image
D) The ability to focus light onto a specimen
🔴 Correct Answer: B – Contrast is the difference in light absorbance between two objects.
Poor contrast gives a high background and makes visualization of multiple objects difficult.
🟢 11. Which microscope component controls the amount of light that passes through the
sample and into the objective lens?
A) Objective lens
B) Condenser
🟢 C) Iris diaphragm
D) Eyepiece
🔴 Correct Answer: C – The iris diaphragm controls the amount of light that passes through
the sample and into the objective lens. It can be adjusted (opened or closed) to alter the
amount of light.
🟢 12. What is the total magnification when using a 60x objective and a 10x eyepiece?
A) 60x
B) 70x
C) 600x
D) 6,000x
🔴 Correct Answer: C – Total magnification = objective magnification × eyepiece
magnification = 60 × 10 = 600x.
🟢 13. What is the total magnification when using a 100x objective and a 10x eyepiece?
A) 110x
🟢 B) 1,000x
C) 10,000x
D) 100,000x
🔴 Correct Answer: B – Total magnification = objective magnification × eyepiece
magnification = 100 × 10 = 1,000x.
🟢 14. What is the total magnification when using a 40x objective and a 15x eyepiece?
A) 55x
B) 400x
🟢 C) 600x
D) 4,000x
🔴 Correct Answer: C – Total magnification = 40 × 15 = 600x.
, 🟢 15. Which lens is closest to the specimen and provides the greatest magnification?
A) Ocular lens
B) Condenser lens
🟢 C) Objective lens
D) Iris diaphragm
🔴 Correct Answer: C – The objective lens is nearest to the specimen and provides the primary
magnification.
🟢 16. What is the typical magnification of the ocular (eyepiece) lens?
A) 4x
🟢 B) 10x
C) 40x
D) 100x
🔴 Correct Answer: B – The ocular lens typically provides 10x magnification.
🟢 17. Which of the following would you adjust to limit the amount of light entering the
microscope, assuming a constant light source?
A) Objective
B) Condenser
🟢 C) Iris diaphragm
D) Eyepiece
🔴 Correct Answer: C – The iris diaphragm is the component that controls light entry; it can be
opened or closed to regulate light passing through the sample.
🟢 18. Which microscope component holds the slide in place on the microscope stage?
A) Condenser
B) Objective
C) Ocular
🟢 D) Stage clips
🔴 Correct Answer: D – Stage clips (or mechanical stage controls) hold the slide securely in
place on the stage.
🟢 19. The condenser on a light microscope functions to:
A) Magnify the image
🟢 B) Focus and concentrate light onto the specimen
C) Control the amount of light entering the objective
D) Hold the slide in place
🔴 Correct Answer: B – The condenser focuses and concentrates light onto the specimen to
improve illumination and resolution.
Comprehensive Multiple-Choice Question Bank (150 Questions)
SECTION 1: MICROSCOPY FUNDAMENTALS & MEASUREMENT
🟢 1. A nanometer is defined as which of the following?
A) 10⁻³ meters
B) 10⁻⁶ meters
🟢 C) 10⁻⁹ meters
D) 10⁻¹² meters
🔴 Correct Answer: C – A nanometer is one-billionth of a meter (10⁻⁹ m). A micrometer is 10⁻⁶
m, and a millimeter is 10⁻³ m.
🟢 2. A micrometer is defined as:
A) 10⁻³ meters
🟢 B) 10⁻⁶ meters
C) 10⁻⁹ meters
D) 10⁻¹² meters
🔴 Correct Answer: B – A micrometer (μm) is one-millionth of a meter (10⁻⁶ m), commonly
used to measure the size of cells.
🟢 3. True or False: A nanometer is longer than a micrometer.
🟢 A) True
B) False
🔴 Correct Answer: B (False) – A nanometer is 1,000 times smaller than a micrometer.
Specifically, 1 μm = 1,000 nm.
🟢 4. Which unit of measurement is most appropriate for measuring the size of a typical
bacterial cell?
A) Nanometer
🟢 B) Micrometer
C) Millimeter
D) Centimeter
🔴 Correct Answer: B – Bacterial cells are typically measured in micrometers (μm), with most
ranging from 0.5 to 5.0 μm in diameter.
🟢 5. Which unit of measurement is most appropriate for measuring viruses and cellular
organelles?
,🟢 A) Nanometer
B) Micrometer
C) Millimeter
D) Centimeter
🔴 Correct Answer: A – Nanometers (nm) are used to measure viruses, cellular organelles, and
macromolecules. A typical virus ranges from 20–300 nm.
🟢 6. A bacterium has a diameter of 0.5 μm. What is this measurement in nanometers?
A) 5 nm
B) 50 nm
🟢 C) 500 nm
D) 5,000 nm
🔴 Correct Answer: C – 1 μm = 1,000 nm, so 0.5 μm × 1,000 = 500 nm.
🟢 7. The unaided human eye can reliably resolve objects approximately larger than:
A) 1 μm
B) 10 μm
C) 50 μm
🟢 D) 100 μm
🔴 Correct Answer: D – The unaided eye can, on average, clearly resolve objects greater than
100 μm (0.1 mm).
🟢 8. Which of the following could NOT be seen clearly by the unaided eye? Select all that
apply.
A) Protozoa with diameter of 150 μm
🟢 B) Bacteria with diameter of 24 μm
C) Skin cell with diameter of 1,500 μm
🟢 D) Virus with diameter of 0.2 μm
🔴 Correct Answer: B and D – The unaided eye can resolve objects > 100 μm. Bacteria (24 μm)
and viruses (0.2 μm) fall below this threshold and require microscopy.
🟢 9. Resolution is best defined as:
A) The ability to make an image appear larger
🟢 B) The ability to distinguish two adjacent points as separate entities
C) The difference in light intensity between the specimen and background
D) The ability to add color to a specimen
🔴 Correct Answer: B – Resolution refers to the distance between two objects at which they
can still be seen as separate. Poor resolution causes two or more objects to appear as one.
🟢 10. Contrast is best defined as:
,A) The ability to distinguish two adjacent points as separate
🟢 B) The difference in light absorbance between two objects
C) The total magnification of an image
D) The ability to focus light onto a specimen
🔴 Correct Answer: B – Contrast is the difference in light absorbance between two objects.
Poor contrast gives a high background and makes visualization of multiple objects difficult.
🟢 11. Which microscope component controls the amount of light that passes through the
sample and into the objective lens?
A) Objective lens
B) Condenser
🟢 C) Iris diaphragm
D) Eyepiece
🔴 Correct Answer: C – The iris diaphragm controls the amount of light that passes through
the sample and into the objective lens. It can be adjusted (opened or closed) to alter the
amount of light.
🟢 12. What is the total magnification when using a 60x objective and a 10x eyepiece?
A) 60x
B) 70x
C) 600x
D) 6,000x
🔴 Correct Answer: C – Total magnification = objective magnification × eyepiece
magnification = 60 × 10 = 600x.
🟢 13. What is the total magnification when using a 100x objective and a 10x eyepiece?
A) 110x
🟢 B) 1,000x
C) 10,000x
D) 100,000x
🔴 Correct Answer: B – Total magnification = objective magnification × eyepiece
magnification = 100 × 10 = 1,000x.
🟢 14. What is the total magnification when using a 40x objective and a 15x eyepiece?
A) 55x
B) 400x
🟢 C) 600x
D) 4,000x
🔴 Correct Answer: C – Total magnification = 40 × 15 = 600x.
, 🟢 15. Which lens is closest to the specimen and provides the greatest magnification?
A) Ocular lens
B) Condenser lens
🟢 C) Objective lens
D) Iris diaphragm
🔴 Correct Answer: C – The objective lens is nearest to the specimen and provides the primary
magnification.
🟢 16. What is the typical magnification of the ocular (eyepiece) lens?
A) 4x
🟢 B) 10x
C) 40x
D) 100x
🔴 Correct Answer: B – The ocular lens typically provides 10x magnification.
🟢 17. Which of the following would you adjust to limit the amount of light entering the
microscope, assuming a constant light source?
A) Objective
B) Condenser
🟢 C) Iris diaphragm
D) Eyepiece
🔴 Correct Answer: C – The iris diaphragm is the component that controls light entry; it can be
opened or closed to regulate light passing through the sample.
🟢 18. Which microscope component holds the slide in place on the microscope stage?
A) Condenser
B) Objective
C) Ocular
🟢 D) Stage clips
🔴 Correct Answer: D – Stage clips (or mechanical stage controls) hold the slide securely in
place on the stage.
🟢 19. The condenser on a light microscope functions to:
A) Magnify the image
🟢 B) Focus and concentrate light onto the specimen
C) Control the amount of light entering the objective
D) Hold the slide in place
🔴 Correct Answer: B – The condenser focuses and concentrates light onto the specimen to
improve illumination and resolution.
