Microbiology LAB Exam 2026 Questions
and Answers
Microscope- The Condenser - Correct answer-focuses the light ging into the
objective lens
Microscope- The Iris Diaphragm - Correct answer-adjusts the amount of light
going into the objective lens
Microscope- Nosepiece - Correct answer-holds the objective lenses and rotates to
change from one objective to another
Microscope- Coarse Objective Knob - Correct answer-moves the stage larger
distances to help get the object in focus
Microscope- Fine Adjustment Knob - Correct answer-moves the stage smaler
increments to help get the object in better focus
Microscope- Objective Lens - Correct answer-magnifies the object. It is located
near the object.
Microscope- Occular Lens - Correct answer-magnifies the image of the object
from the objective lens. It is located near the eye.
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,Steps in using the microscope - Correct answer-1) scanner power in place
2) place slide of specimen stage in place with stage clips
3) Using the course adjustment knob, raise the stage all the way up and then down
slowly until you can see image of specimen
4) Readjust with fine adjustment knob
Describe the purpose of the oil immersion lens - Correct answer-Used when oil is
added to the slide. Oil must touch the object and objective lens to that the light
does not refract futher
Parfocal - Correct answer-Parfocal microscopes are able to move from one
objective to the next and still be in focus due to the length of the objective lenses
Resolution - Correct answer-The ability to distinguish between two objects that are
very close together.
What is resolving power? - Correct answer-The measurement of resolution
What are two ways to increase resolving power? - Correct answer-1. By decreasing
the wavelength of light (using a blue filter) 2. Increasing the numerical aperature
What units are used to express resolving power? - Correct answer-nm or
nanometers
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, What is better, smaller or larger resolving power? - Correct answer-Smaller is
better
Light microscopes have a 200nm resolving power
Electron microscopes have a .2nm resolving power
What is chromatic aberration? - Correct answer-The effect when many colors are
seen toward the edge of the microscope field of vision (like a prisim)
How are microscopes corrected for chromatic aberration? - Correct answer-With a
special achromatic lens (corrected for red and blue light) or by using a blue filter.
The lab has blue filters in their microscopes which also increase resolution.
Describe the process of making a wet-mount slide - Correct answer-1) Add the
specimen to the slide
2) Touch the edge of the cover slip with one edge of drop of specimen.
3) Let the cover slip drop gradually to the slide, covering the drop of specimen.
Describe the purpose of making a wet-mount slide - Correct answer-To be able to
see living organisms under the microscope in their natural state.
What is the advantage of using a wet-mount slide? - Correct answer-Can see
movement and determine if microbes posses their own method of motility. Can
also see the actual shape and arrangement of microbes.
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and Answers
Microscope- The Condenser - Correct answer-focuses the light ging into the
objective lens
Microscope- The Iris Diaphragm - Correct answer-adjusts the amount of light
going into the objective lens
Microscope- Nosepiece - Correct answer-holds the objective lenses and rotates to
change from one objective to another
Microscope- Coarse Objective Knob - Correct answer-moves the stage larger
distances to help get the object in focus
Microscope- Fine Adjustment Knob - Correct answer-moves the stage smaler
increments to help get the object in better focus
Microscope- Objective Lens - Correct answer-magnifies the object. It is located
near the object.
Microscope- Occular Lens - Correct answer-magnifies the image of the object
from the objective lens. It is located near the eye.
©COPYRIGHT 2025, ALL RIGHTS RESERVE 1
,Steps in using the microscope - Correct answer-1) scanner power in place
2) place slide of specimen stage in place with stage clips
3) Using the course adjustment knob, raise the stage all the way up and then down
slowly until you can see image of specimen
4) Readjust with fine adjustment knob
Describe the purpose of the oil immersion lens - Correct answer-Used when oil is
added to the slide. Oil must touch the object and objective lens to that the light
does not refract futher
Parfocal - Correct answer-Parfocal microscopes are able to move from one
objective to the next and still be in focus due to the length of the objective lenses
Resolution - Correct answer-The ability to distinguish between two objects that are
very close together.
What is resolving power? - Correct answer-The measurement of resolution
What are two ways to increase resolving power? - Correct answer-1. By decreasing
the wavelength of light (using a blue filter) 2. Increasing the numerical aperature
What units are used to express resolving power? - Correct answer-nm or
nanometers
©COPYRIGHT 2025, ALL RIGHTS RESERVE 2
, What is better, smaller or larger resolving power? - Correct answer-Smaller is
better
Light microscopes have a 200nm resolving power
Electron microscopes have a .2nm resolving power
What is chromatic aberration? - Correct answer-The effect when many colors are
seen toward the edge of the microscope field of vision (like a prisim)
How are microscopes corrected for chromatic aberration? - Correct answer-With a
special achromatic lens (corrected for red and blue light) or by using a blue filter.
The lab has blue filters in their microscopes which also increase resolution.
Describe the process of making a wet-mount slide - Correct answer-1) Add the
specimen to the slide
2) Touch the edge of the cover slip with one edge of drop of specimen.
3) Let the cover slip drop gradually to the slide, covering the drop of specimen.
Describe the purpose of making a wet-mount slide - Correct answer-To be able to
see living organisms under the microscope in their natural state.
What is the advantage of using a wet-mount slide? - Correct answer-Can see
movement and determine if microbes posses their own method of motility. Can
also see the actual shape and arrangement of microbes.
©COPYRIGHT 2025, ALL RIGHTS RESERVE 3
