,BIOD 171 Module 3 | Practice Q&A | 2026/2027 | Microbiology |
Portage Learning
1. Which metric unit is commonly used in microbiology to measure the size
of bacterial cells?
A) Nanometer (nm)
B) Micrometer (µm)
C) Millimeter (mm)
D) Kilometer (km)
Correct Answer: Micrometer (µm)
Rationale: Most bacteria are between 1–10 µm in size, making the
micrometer the standard unit of measurement for bacterial cells. Viruses,
which are much smaller, are typically measured in nanometers.
2. A nanometer is defined as:
A) 10⁻³ meters
B) 10⁻⁶ meters
C) 10⁻⁹ meters
D) 10⁻¹² meters
Correct Answer: 10⁻⁹ meters
Rationale: A nanometer is one-billionth of a meter (10⁻⁹ m). A micrometer is
10⁻⁶ m, a millimeter is 10⁻³ m, and a picometer is 10⁻¹² m.
3. True or False: A nanometer is longer than a micrometer.
A) True
,B) False
Correct Answer: False
Rationale: A nanometer is 1,000 times smaller than a micrometer. One
micrometer equals 1,000 nanometers. Therefore, a nanometer is shorter
than a micrometer.
4. A micrometer is defined as:
A) 10⁻³ meters
B) 10⁻⁶ meters
C) 10⁻⁹ meters
D) 10⁻¹² meters
Correct Answer: 10⁻⁶ meters
Rationale: A micrometer is one-millionth of a meter (10⁻⁶ m). This is the
standard unit for measuring bacterial cells, which typically range from 1–10
µm in size.
5. Resolution is best defined as the:
A) Ability to make an object appear larger
B) Ability to distinguish two points that are close together as separate
C) Difference in light absorbance between a specimen and the background
D) Ability to see the internal organelles of a virus
Correct Answer: Ability to distinguish two points that are close together as
separate
, Rationale: Resolution determines the clarity of an image. If resolution is poor,
two distinct objects will appear as a single blurred image.
6. Contrast is best defined as the:
A) Ability to make an object appear larger
B) Ability to distinguish two close points as separate
C) Difference in light absorbance between a specimen and the background
D) Ability to see internal structures
Correct Answer: Difference in light absorbance between a specimen and the
background
Rationale: Contrast is the difference in light absorbance between two objects.
Poor contrast gives a high background and makes visualization of multiple
objects difficult.
7. What is the total magnification of a specimen viewed with a 10x ocular
lens and a 40x objective lens?
A) 50x
B) 100x
C) 400x
D) 4,000x
Correct Answer: 400x
Rationale: Total magnification is calculated by multiplying the ocular lens
power by the objective lens power: 10 × 40 = 400x magnification.
Portage Learning
1. Which metric unit is commonly used in microbiology to measure the size
of bacterial cells?
A) Nanometer (nm)
B) Micrometer (µm)
C) Millimeter (mm)
D) Kilometer (km)
Correct Answer: Micrometer (µm)
Rationale: Most bacteria are between 1–10 µm in size, making the
micrometer the standard unit of measurement for bacterial cells. Viruses,
which are much smaller, are typically measured in nanometers.
2. A nanometer is defined as:
A) 10⁻³ meters
B) 10⁻⁶ meters
C) 10⁻⁹ meters
D) 10⁻¹² meters
Correct Answer: 10⁻⁹ meters
Rationale: A nanometer is one-billionth of a meter (10⁻⁹ m). A micrometer is
10⁻⁶ m, a millimeter is 10⁻³ m, and a picometer is 10⁻¹² m.
3. True or False: A nanometer is longer than a micrometer.
A) True
,B) False
Correct Answer: False
Rationale: A nanometer is 1,000 times smaller than a micrometer. One
micrometer equals 1,000 nanometers. Therefore, a nanometer is shorter
than a micrometer.
4. A micrometer is defined as:
A) 10⁻³ meters
B) 10⁻⁶ meters
C) 10⁻⁹ meters
D) 10⁻¹² meters
Correct Answer: 10⁻⁶ meters
Rationale: A micrometer is one-millionth of a meter (10⁻⁶ m). This is the
standard unit for measuring bacterial cells, which typically range from 1–10
µm in size.
5. Resolution is best defined as the:
A) Ability to make an object appear larger
B) Ability to distinguish two points that are close together as separate
C) Difference in light absorbance between a specimen and the background
D) Ability to see the internal organelles of a virus
Correct Answer: Ability to distinguish two points that are close together as
separate
, Rationale: Resolution determines the clarity of an image. If resolution is poor,
two distinct objects will appear as a single blurred image.
6. Contrast is best defined as the:
A) Ability to make an object appear larger
B) Ability to distinguish two close points as separate
C) Difference in light absorbance between a specimen and the background
D) Ability to see internal structures
Correct Answer: Difference in light absorbance between a specimen and the
background
Rationale: Contrast is the difference in light absorbance between two objects.
Poor contrast gives a high background and makes visualization of multiple
objects difficult.
7. What is the total magnification of a specimen viewed with a 10x ocular
lens and a 40x objective lens?
A) 50x
B) 100x
C) 400x
D) 4,000x
Correct Answer: 400x
Rationale: Total magnification is calculated by multiplying the ocular lens
power by the objective lens power: 10 × 40 = 400x magnification.
