BIOD 171 Exam 3 Study 2026 Questions
and Answers
True or False: A nanometer (10-9) is longer than a micrometer (10-6). - Correct
answer-False; A nanometer is 1,000 times smaller than a micrometer.
Resolution and contrast are two critical factors that influence your ability to see an
object. Explain each. - Correct answer-Resolution is the difference in distance
between two objects that appear as two separate objects.
Contrast is the difference in light absorption by an object.
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.
- Correct answer-Iris diaphragm
What is the total magnification (relative to your eye) of a sample imaged with a
60x objective and a 10x eyepiece? Show your math. - Correct answer-60 x 10 =
600x magnification
True or False: Staining is often required to image a cell that is adherent and flat
(thin). - Correct answer-True
©COPYRIGHT 2025, ALL RIGHTS RESERVED 1
, Which of the following could NOT be seen clearly by the unaided eye? Select all
that apply. - Correct answer-Bacteria with diameter of 24 μm
Virus with a diameter of 0.2 μm
This type of microscope utilizes ultraviolet (UV) light to illuminate stained objects.
- Correct answer-Fluorescence
This type of microscope can provide detailed images of live cells without staining.
- Correct answer-Phase-Contrast
This type of microscope enhances contrast between specimen and background but
does not permit the visualization of intracellular structures. - Correct answer-Dark
Field
This type of microscope is capable of capturing images in multiple focal planes,
rendering a specimen in 3-D. - Correct answer-Confocal
Identify what type of electron microscope was used to capture the following image
and explain your choice. - Correct answer-SEM. It appears that the electrons
reflected off of the sample creating a shell. Only TEM is capable of visualizing
subcellular substrucutres.
©COPYRIGHT 2025, ALL RIGHTS RESERVED 2
and Answers
True or False: A nanometer (10-9) is longer than a micrometer (10-6). - Correct
answer-False; A nanometer is 1,000 times smaller than a micrometer.
Resolution and contrast are two critical factors that influence your ability to see an
object. Explain each. - Correct answer-Resolution is the difference in distance
between two objects that appear as two separate objects.
Contrast is the difference in light absorption by an object.
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.
- Correct answer-Iris diaphragm
What is the total magnification (relative to your eye) of a sample imaged with a
60x objective and a 10x eyepiece? Show your math. - Correct answer-60 x 10 =
600x magnification
True or False: Staining is often required to image a cell that is adherent and flat
(thin). - Correct answer-True
©COPYRIGHT 2025, ALL RIGHTS RESERVED 1
, Which of the following could NOT be seen clearly by the unaided eye? Select all
that apply. - Correct answer-Bacteria with diameter of 24 μm
Virus with a diameter of 0.2 μm
This type of microscope utilizes ultraviolet (UV) light to illuminate stained objects.
- Correct answer-Fluorescence
This type of microscope can provide detailed images of live cells without staining.
- Correct answer-Phase-Contrast
This type of microscope enhances contrast between specimen and background but
does not permit the visualization of intracellular structures. - Correct answer-Dark
Field
This type of microscope is capable of capturing images in multiple focal planes,
rendering a specimen in 3-D. - Correct answer-Confocal
Identify what type of electron microscope was used to capture the following image
and explain your choice. - Correct answer-SEM. It appears that the electrons
reflected off of the sample creating a shell. Only TEM is capable of visualizing
subcellular substrucutres.
©COPYRIGHT 2025, ALL RIGHTS RESERVED 2
