Bio 271 Module 3 Exam Questions with Correct
Answers
A micrometer is defined as:
10^-6
Resolution and contrast are two critical factors that influence your ability to see an
object. Explain each.
Resolution is the distance between objects at which they appear separate. Poor resolution can
show two or more objects as just one.
Contrast is the difference in light absorption between two objects. Poor contrast can make the
visualization of multiple object difficult.
Assuming a fixed ocular, identify the part of the microscope you would adjust to
enhance the magnification of a sample.
Objective
What is the total magnification (relative to your eye) of a sample imaged with a 60x
objective and a 10x eyepiece?
10 x 60 = 600x
True or false: A cell that is adherent, flat, and unstained is easily identified using bright
field microscopy.
False. Adherent, flat cells are almost invisible due to the limits on both resolution and
contrast.
, Which of the following could be seen clearly by the unaided eye. Select all that apply.
A. Virus with a diameter of 0.2 micrometers
B. Bacteria with a diameter of 24 micrometers
C. Skin cell with a diameter of 1500 micrometers
D. Protozoa with a diameter of 150 micrometers
C and D. The unaided eye can see objects >150 micrometers.
Label the following microscope components.
Answers:
1. F
2. D
3. B
4. G
5. A
6. H
Options:
A. Stage
B. Fine adjustment knob
C. Iris diaphragm
D. Neck
E. Condenser lens
F. Eyepiece
G. Objective
Answers
A micrometer is defined as:
10^-6
Resolution and contrast are two critical factors that influence your ability to see an
object. Explain each.
Resolution is the distance between objects at which they appear separate. Poor resolution can
show two or more objects as just one.
Contrast is the difference in light absorption between two objects. Poor contrast can make the
visualization of multiple object difficult.
Assuming a fixed ocular, identify the part of the microscope you would adjust to
enhance the magnification of a sample.
Objective
What is the total magnification (relative to your eye) of a sample imaged with a 60x
objective and a 10x eyepiece?
10 x 60 = 600x
True or false: A cell that is adherent, flat, and unstained is easily identified using bright
field microscopy.
False. Adherent, flat cells are almost invisible due to the limits on both resolution and
contrast.
, Which of the following could be seen clearly by the unaided eye. Select all that apply.
A. Virus with a diameter of 0.2 micrometers
B. Bacteria with a diameter of 24 micrometers
C. Skin cell with a diameter of 1500 micrometers
D. Protozoa with a diameter of 150 micrometers
C and D. The unaided eye can see objects >150 micrometers.
Label the following microscope components.
Answers:
1. F
2. D
3. B
4. G
5. A
6. H
Options:
A. Stage
B. Fine adjustment knob
C. Iris diaphragm
D. Neck
E. Condenser lens
F. Eyepiece
G. Objective
