BIOD 171 Module 3 Exam Questions & Answers |
Biology Study Guide | Actual Questions with
Revised Answers, 100% Verified and Updated
Already Graded A+|Latest Exam and Brand new
Version!!!
A nanometer is defined as:
CORRECT ANSWER:
10 -9 or one-billionth of a meter
True or False: A nanometer is longer than a micrometer
CORRECT ANSWER:
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 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).
Assuming a fixed ocular, identify the part of the microscope you would
adjust to enhance the magnification of a sample.
CORRECT ANSWER:
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 ANSWER:
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 ANSWER:
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 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.
,True or False: A cell that is adherent, flat (thin), and unstained is easily
identified using bright field microscopy
CORRECT ANSWER:
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 ANSWER:
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 ANSWER:
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 ANSWER:
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 ANSWER:
Fluorescence
This type of microscope utilizes ultraviolet (UV) light to illuminate
stained objects.
CORRECT ANSWER:
Fluorescence
This type of microscope uses a specialized condenser and objective
to amplify the slight differences between cells and background.
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 uses neither halogen nor UV light sources but
rather lasers to illuminate stained cells in high resolution.
Biology Study Guide | Actual Questions with
Revised Answers, 100% Verified and Updated
Already Graded A+|Latest Exam and Brand new
Version!!!
A nanometer is defined as:
CORRECT ANSWER:
10 -9 or one-billionth of a meter
True or False: A nanometer is longer than a micrometer
CORRECT ANSWER:
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 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).
Assuming a fixed ocular, identify the part of the microscope you would
adjust to enhance the magnification of a sample.
CORRECT ANSWER:
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 ANSWER:
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 ANSWER:
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 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.
,True or False: A cell that is adherent, flat (thin), and unstained is easily
identified using bright field microscopy
CORRECT ANSWER:
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 ANSWER:
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 ANSWER:
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 ANSWER:
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 ANSWER:
Fluorescence
This type of microscope utilizes ultraviolet (UV) light to illuminate
stained objects.
CORRECT ANSWER:
Fluorescence
This type of microscope uses a specialized condenser and objective
to amplify the slight differences between cells and background.
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 uses neither halogen nor UV light sources but
rather lasers to illuminate stained cells in high resolution.
