BIOD 171 MODULE 3 ESSENTIAL
MICROBIOLOGY CERTIFICATION TEST
PAPER COMPLETE QUESTIONS AND
CORRECT ANSWERS FULL SOLUTION
GUIDE
●● True or False: A nanometer is longer than a micrometer
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.
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.
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.
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.
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).
Answer: True
MICROBIOLOGY CERTIFICATION TEST
PAPER COMPLETE QUESTIONS AND
CORRECT ANSWERS FULL SOLUTION
GUIDE
●● True or False: A nanometer is longer than a micrometer
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.
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.
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.
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.
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).
Answer: True
