BIOD 171 Essential Microbiology Portage Learning Module 3
Real Exam Questions & 100% Correct Answers (Verified) — A+ Grade
1. A nanometer is defined as:
Answer: 10 -9 or one-billionth of a meter
2. True or False: A nanometer is longer than a micrometer
Answer: False A nanometer is 1000x smaller than a micrometer
3. Resolution and contrast are two critical factors that influence
your ability to see an object Explain each
Answer: Resolution refers to the distance between two objects at which the objects can
still be seen as separate Poor or low resolution means two or more objects may appear as
one Contrast on the other hand is the difference in light absorbance between two objects
Poor contrast gives a high background and makes the visualization of multiple objects
difficult For instance, trying to identify 2 dark colored objects at night (low light = low
contrast) versus the same 2 objects in the middle of a sunny afternoon (bright light against
2 dark objects = high contrast
4. Assuming a fixed ocular, identify the part of the microscope
you would adjust to enhance the magnification of a sample
Answer: Objective Only the oculars (eyepiece) and the objectives contribute to the mag-
nification of the sample Since the eyepiece is fixed, only the objectives could be altered
5. Assuming a constant (non-adjustable) light source power,
identify the part of the microscope you would adjust to limit the
amount of light entering the microscope
Answer: Iris diaphragm
SuccessShelf2 © 2025 SuccessShelf2. For Personal Use Only. All rights reserved.
, BIOD 171 Essential Microbiology Portage Learning Module 3
Real Exam Questions & 100% Correct Answers (Verified) — A+ Grade
6. What is the total magnification on (relative to your eye) of a
sample imaged with a 60x objective and a 10x eyepiece? Show
your math
Answer: 60x objective x 10x ocular = 600x magnification
7. True or False: Staining is often required to image a cell that
is adherent and flat (thin
Answer: True.
Adherent, flat and unstained cells are almost invisible due to the limits on both resolution
and contrast Therefore, cell staining is often required to adequately image the sample
8. True or False: A cell that is adherent, flat (thin) , and un-
stained is easily identified using bright field microscopy
Answer: False: Adherent, flat cells are almost invisible due to the limits on both resolu-
tion and contrast
9. Which of the following could be seen clearly by the unaided
eye? Select all that apply
A. Bacteria with a diameter of 24 µm
B. Protozoa with a diameter of 150 µm
C. Virus with a diameter of 0.2 µm
D. Skin cell with a diameter of 1500 µm
Answer:
B. Protozoa with a diameter of 150 µm,
D. Skin cell with a diameter of 1500 µm.
The unaided eye can, on average, clearly resolve objects larger than 100 µm.
SuccessShelf2 © 2025 SuccessShelf2. For Personal Use Only. All rights reserved.
Real Exam Questions & 100% Correct Answers (Verified) — A+ Grade
1. A nanometer is defined as:
Answer: 10 -9 or one-billionth of a meter
2. True or False: A nanometer is longer than a micrometer
Answer: False A nanometer is 1000x smaller than a micrometer
3. Resolution and contrast are two critical factors that influence
your ability to see an object Explain each
Answer: Resolution refers to the distance between two objects at which the objects can
still be seen as separate Poor or low resolution means two or more objects may appear as
one Contrast on the other hand is the difference in light absorbance between two objects
Poor contrast gives a high background and makes the visualization of multiple objects
difficult For instance, trying to identify 2 dark colored objects at night (low light = low
contrast) versus the same 2 objects in the middle of a sunny afternoon (bright light against
2 dark objects = high contrast
4. Assuming a fixed ocular, identify the part of the microscope
you would adjust to enhance the magnification of a sample
Answer: Objective Only the oculars (eyepiece) and the objectives contribute to the mag-
nification of the sample Since the eyepiece is fixed, only the objectives could be altered
5. Assuming a constant (non-adjustable) light source power,
identify the part of the microscope you would adjust to limit the
amount of light entering the microscope
Answer: Iris diaphragm
SuccessShelf2 © 2025 SuccessShelf2. For Personal Use Only. All rights reserved.
, BIOD 171 Essential Microbiology Portage Learning Module 3
Real Exam Questions & 100% Correct Answers (Verified) — A+ Grade
6. What is the total magnification on (relative to your eye) of a
sample imaged with a 60x objective and a 10x eyepiece? Show
your math
Answer: 60x objective x 10x ocular = 600x magnification
7. True or False: Staining is often required to image a cell that
is adherent and flat (thin
Answer: True.
Adherent, flat and unstained cells are almost invisible due to the limits on both resolution
and contrast Therefore, cell staining is often required to adequately image the sample
8. True or False: A cell that is adherent, flat (thin) , and un-
stained is easily identified using bright field microscopy
Answer: False: Adherent, flat cells are almost invisible due to the limits on both resolu-
tion and contrast
9. Which of the following could be seen clearly by the unaided
eye? Select all that apply
A. Bacteria with a diameter of 24 µm
B. Protozoa with a diameter of 150 µm
C. Virus with a diameter of 0.2 µm
D. Skin cell with a diameter of 1500 µm
Answer:
B. Protozoa with a diameter of 150 µm,
D. Skin cell with a diameter of 1500 µm.
The unaided eye can, on average, clearly resolve objects larger than 100 µm.
SuccessShelf2 © 2025 SuccessShelf2. For Personal Use Only. All rights reserved.
