BIOD 171 MODULE 3 PROFESSIONAL
CERTIFICATION EXAM QUESTIONS AND
ANSWERS
A nanometer is defined as: - Correct ANS~ 10 -9 or one-billionth of a meter
True or False: A nanometer is longer than a micrometer - Correct ANS~ False
A nanometer is 1000x smaller than a micrometer
Resolution and contrast are two critical factors that influence your ability to see an
object. Explain each. - Correct ANS~ 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).
Assuming a fixed ocular, identify the part of the microscope you would adjust to
enhance the magnification of a sample. - Correct ANS~ Objective
Only the oculars (eyepiece) and the objectives contribute to the magnification of the
sample. Since the eyepiece
is fixed, only the objectives could be altered.
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 ANS~ Iris diaphragm
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. - Correct ANS~ 60x objective x
10x ocular = 600x magnification
True or False: Staining is often required to image a cell that is adherent and flat
(thin). - Correct ANS~ 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.
True or False: A cell that is adherent, flat (thin), and unstained is easily identified
using bright field microscopy - Correct ANS~ 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. Bacteria with diameter of 24 μm
B. Protozoa with diameter of 150 μm
C. Virus with a diameter of 0.2 μm
D. Skin cell with diameter of 1500 μm - Correct ANS~ B. Protozoa with diameter of
150 μm
D. Skin cell with diameter of 1500 μm
The unaided eye can, on average, clearly resolve objects > 100 μm
2. Which of the following could NOT be seen clearly by the unaided eye? Select all
that apply.
A. Bacteria with diameter of 24 μm
B. Protozoa with diameter of 150 μm
C. Virus with a diameter of 0.2 μm
D. Skin cell with diameter of 1500 μm - Correct ANS~ A. Bacteria with diameter of
24 μm
C. Virus with a diameter of 0.2 μm
The unaided eye can, on average, clearly resolve objects > 100 μm
1. Label the following unmarked microscope components (numbered arrows) by
matching it with the components provided
(letters). - Correct ANS~ 1F- eyepiece
2D- neck
3B- fine adjustment knob
4G- objective
5A- stage
6H- base
This type of microscope is best suited for visualizing GFP, RFP, and YFP proteins. -
Correct ANS~ Fluorescence
This type of microscope utilizes ultraviolet (UV) light to illuminate stained objects. -
Correct ANS~ Fluorescence
This type of microscope uses a specialized condenser and objective to amplify the
slight differences between cells and background. - Correct ANS~ Phase-contrast
CERTIFICATION EXAM QUESTIONS AND
ANSWERS
A nanometer is defined as: - Correct ANS~ 10 -9 or one-billionth of a meter
True or False: A nanometer is longer than a micrometer - Correct ANS~ False
A nanometer is 1000x smaller than a micrometer
Resolution and contrast are two critical factors that influence your ability to see an
object. Explain each. - Correct ANS~ 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).
Assuming a fixed ocular, identify the part of the microscope you would adjust to
enhance the magnification of a sample. - Correct ANS~ Objective
Only the oculars (eyepiece) and the objectives contribute to the magnification of the
sample. Since the eyepiece
is fixed, only the objectives could be altered.
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 ANS~ Iris diaphragm
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. - Correct ANS~ 60x objective x
10x ocular = 600x magnification
True or False: Staining is often required to image a cell that is adherent and flat
(thin). - Correct ANS~ 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.
True or False: A cell that is adherent, flat (thin), and unstained is easily identified
using bright field microscopy - Correct ANS~ 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. Bacteria with diameter of 24 μm
B. Protozoa with diameter of 150 μm
C. Virus with a diameter of 0.2 μm
D. Skin cell with diameter of 1500 μm - Correct ANS~ B. Protozoa with diameter of
150 μm
D. Skin cell with diameter of 1500 μm
The unaided eye can, on average, clearly resolve objects > 100 μm
2. Which of the following could NOT be seen clearly by the unaided eye? Select all
that apply.
A. Bacteria with diameter of 24 μm
B. Protozoa with diameter of 150 μm
C. Virus with a diameter of 0.2 μm
D. Skin cell with diameter of 1500 μm - Correct ANS~ A. Bacteria with diameter of
24 μm
C. Virus with a diameter of 0.2 μm
The unaided eye can, on average, clearly resolve objects > 100 μm
1. Label the following unmarked microscope components (numbered arrows) by
matching it with the components provided
(letters). - Correct ANS~ 1F- eyepiece
2D- neck
3B- fine adjustment knob
4G- objective
5A- stage
6H- base
This type of microscope is best suited for visualizing GFP, RFP, and YFP proteins. -
Correct ANS~ Fluorescence
This type of microscope utilizes ultraviolet (UV) light to illuminate stained objects. -
Correct ANS~ Fluorescence
This type of microscope uses a specialized condenser and objective to amplify the
slight differences between cells and background. - Correct ANS~ Phase-contrast
