Microbiology LAB Exam #1 Actual
Questions And Detailed Answers
Microscope- The Condenser Detailed Answers focuses the light ging into the objective
lens
Microscope- The Iris Diaphragm Detailed Answers adjusts the amount of light going into
the objective lens
Microscope- Nosepiece Detailed Answers holds the objective lenses and rotates to
change from one objective to another
Microscope- Coarse Objective Knob Detailed Answers moves the stage larger
distances to help get the object in focus
Microscope- Fine Adjustment Knob Detailed Answers moves the stage smaler
increments to help get the object in better focus
Microscope- Objective Lens Detailed Answers magnifies the object. It is located near
the object.
Microscope- Occular Lens Detailed Answers magnifies the image of the object from the
objective lens. It is located near the eye.
Steps in using the microscope Detailed Answers 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 Detailed Answers 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 Detailed Answers 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 Detailed Answers The ability to distinguish between two objects that are very
close together.
What is resolving power? Detailed Answers The measurement of resolution
, What are two ways to increase resolving power? Detailed Answers 1. By decreasing the
wavelength of light (using a blue filter) 2. Increasing the numerical aperature
What units are used to express resolving power? Detailed Answers nm or nanometers
What is better, smaller or larger resolving power? Detailed Answers Smaller is better
Light microscopes have a 200nm resolving power
Electron microscopes have a .2nm resolving power
What is chromatic aberration? Detailed Answers 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? Detailed Answers 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 Detailed Answers 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 Detailed Answers To be able to see
living organisms under the microscope in their natural state.
What is the advantage of using a wet-mount slide? Detailed Answers Can see
movement and determine if microbes posses their own method of motility. Can also see
the actual shape and arrangement of microbes.
What is the dis-advantage of using a wet-mount slide? Detailed Answers The
movement is very fast, microbes are transparent. Must use a "dark-field stop".
What is a producer? Detailed Answers Are autotroph organisms that make their own
food (through photosynthesis).
What structure is an indicator of a producer? Detailed Answers Chloroplasts is an
indicator that an organism is a producer.
An example of a producer is what? Detailed Answers Algae are producers that are
found in a pond.
What is a consumer? Detailed Answers They are heterotrophic organisms that get their
food from another source (nonphotosynthetic)
Examples of a consumer are what? Detailed Answers Protozoans such as paramecium
and multicellular animals like rotifers or daphnia.
Questions And Detailed Answers
Microscope- The Condenser Detailed Answers focuses the light ging into the objective
lens
Microscope- The Iris Diaphragm Detailed Answers adjusts the amount of light going into
the objective lens
Microscope- Nosepiece Detailed Answers holds the objective lenses and rotates to
change from one objective to another
Microscope- Coarse Objective Knob Detailed Answers moves the stage larger
distances to help get the object in focus
Microscope- Fine Adjustment Knob Detailed Answers moves the stage smaler
increments to help get the object in better focus
Microscope- Objective Lens Detailed Answers magnifies the object. It is located near
the object.
Microscope- Occular Lens Detailed Answers magnifies the image of the object from the
objective lens. It is located near the eye.
Steps in using the microscope Detailed Answers 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 Detailed Answers 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 Detailed Answers 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 Detailed Answers The ability to distinguish between two objects that are very
close together.
What is resolving power? Detailed Answers The measurement of resolution
, What are two ways to increase resolving power? Detailed Answers 1. By decreasing the
wavelength of light (using a blue filter) 2. Increasing the numerical aperature
What units are used to express resolving power? Detailed Answers nm or nanometers
What is better, smaller or larger resolving power? Detailed Answers Smaller is better
Light microscopes have a 200nm resolving power
Electron microscopes have a .2nm resolving power
What is chromatic aberration? Detailed Answers 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? Detailed Answers 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 Detailed Answers 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 Detailed Answers To be able to see
living organisms under the microscope in their natural state.
What is the advantage of using a wet-mount slide? Detailed Answers Can see
movement and determine if microbes posses their own method of motility. Can also see
the actual shape and arrangement of microbes.
What is the dis-advantage of using a wet-mount slide? Detailed Answers The
movement is very fast, microbes are transparent. Must use a "dark-field stop".
What is a producer? Detailed Answers Are autotroph organisms that make their own
food (through photosynthesis).
What structure is an indicator of a producer? Detailed Answers Chloroplasts is an
indicator that an organism is a producer.
An example of a producer is what? Detailed Answers Algae are producers that are
found in a pond.
What is a consumer? Detailed Answers They are heterotrophic organisms that get their
food from another source (nonphotosynthetic)
Examples of a consumer are what? Detailed Answers Protozoans such as paramecium
and multicellular animals like rotifers or daphnia.
