2025-2026 SERIES
MICROBIOLOGY LAB EXAM #1 COMPLETE
QUESTIONS AND CORRECT ANSWERS | GRADED
AND THE LATEST SERIES
Microscope- The Condenser
Ans: focuses the light ging into the objective lens
Question: Microscope- The Iris Diaphragm
Ans: adjusts the amount of light going into the objective lens
Question: Microscope- Nosepiece
Ans: holds the objective lenses and rotates to change from one objective to
another
Question: Microscope- Coarse Objective Knob
Ans: moves the stage larger distances to help get the object in focus
Question: Microscope- Fine Adjustment Knob
Ans: moves the stage smaler increments to help get the object in better focus
Question: Microscope- Objective Lens
Ans: magnifies the object. It is located near the object.
Question: Microscope- Occular Lens
, 2025-2026 SERIES
Ans: magnifies the image of the object from the objective lens. It is located near
the eye.
Question: Steps in using the microscope
Ans: 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
Question: Describe the purpose of the oil immersion lens
Ans: Used when oil is added to the slide. Oil must touch the object and objective
lens to that the light does not refract futher
Question: Parfocal
Ans: 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
Question: Resolution
Ans: The ability to distinguish between two objects that are very close together.
Question: What is resolving power?
Ans: The measurement of resolution
Question: What are two ways to increase resolving power?
, 2025-2026 SERIES
Ans: 1. By decreasing the wavelength of light (using a blue filter) 2. Increasing
the numerical aperature
Question: What units are used to express resolving power?
Ans: nm or nanometers
Question: What is better, smaller or larger resolving power?
Ans: Smaller is better
Light microscopes have a 200nm resolving power
Electron microscopes have a .2nm resolving power
Question: What is chromatic aberration?
Ans: The effect when many colors are seen toward the edge of the microscope
field of vision (like a prisim)
Question: How are microscopes corrected for chromatic aberration?
Ans: 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.
Question: Describe the process of making a wet-mount slide
Ans: 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.
MICROBIOLOGY LAB EXAM #1 COMPLETE
QUESTIONS AND CORRECT ANSWERS | GRADED
AND THE LATEST SERIES
Microscope- The Condenser
Ans: focuses the light ging into the objective lens
Question: Microscope- The Iris Diaphragm
Ans: adjusts the amount of light going into the objective lens
Question: Microscope- Nosepiece
Ans: holds the objective lenses and rotates to change from one objective to
another
Question: Microscope- Coarse Objective Knob
Ans: moves the stage larger distances to help get the object in focus
Question: Microscope- Fine Adjustment Knob
Ans: moves the stage smaler increments to help get the object in better focus
Question: Microscope- Objective Lens
Ans: magnifies the object. It is located near the object.
Question: Microscope- Occular Lens
, 2025-2026 SERIES
Ans: magnifies the image of the object from the objective lens. It is located near
the eye.
Question: Steps in using the microscope
Ans: 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
Question: Describe the purpose of the oil immersion lens
Ans: Used when oil is added to the slide. Oil must touch the object and objective
lens to that the light does not refract futher
Question: Parfocal
Ans: 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
Question: Resolution
Ans: The ability to distinguish between two objects that are very close together.
Question: What is resolving power?
Ans: The measurement of resolution
Question: What are two ways to increase resolving power?
, 2025-2026 SERIES
Ans: 1. By decreasing the wavelength of light (using a blue filter) 2. Increasing
the numerical aperature
Question: What units are used to express resolving power?
Ans: nm or nanometers
Question: What is better, smaller or larger resolving power?
Ans: Smaller is better
Light microscopes have a 200nm resolving power
Electron microscopes have a .2nm resolving power
Question: What is chromatic aberration?
Ans: The effect when many colors are seen toward the edge of the microscope
field of vision (like a prisim)
Question: How are microscopes corrected for chromatic aberration?
Ans: 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.
Question: Describe the process of making a wet-mount slide
Ans: 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.
