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MICROBIOLOGY LAB EXAM QUESTIONS AND
ANSWERS VERIFIED
1.Microscope- The Condenser: focuses the light ging into the objective lens
2.Microscope- The Iris Diaphragm: adjusts the amount of light going into the objective
lens
3.Microscope- Nosepiece: holds the objective lenses and rotates to change from one
objective to another 4. Microscope- Coarse Objective Knob: moves the stage larger
distances to help get the object in focus
5.Microscope- Fine Adjustment Knob: moves the stage smaler increments to help get the
object in better focus
6.Microscope- Objective Lens: magnifies the object. It is located near the object.
7.Microscope- Occular Lens: magnifies the image of the object from the objective lens. It
is located near the eye.
8.Steps in using the microscope: 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
9. Describe the purpose of the oil immersion lens: Used when oil is added to the slide.
Oil must touch the object and objective lens to that the light does not refract futher
10. Parfocal: 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
11. Resolution: The ability to distinguish between two objects that are very close
together.
12. What is resolving power?: The measurement of resolution
13. What are two ways to increase resolving power?: 1. By decreasing the wavelength
of light
(using a blue filter) 2. Increasing the numerical aperature
, 14. What units are used to express resolving power?: nm or nanometers
15. What is better, smaller or larger resolving power?: Smaller is better
Light microscopes have a 200nm resolving power
Electron microscopes have a .2nm resolving power
16. What is chromatic aberration?: The effect when many colors are seen toward the
edge of the microscope field of vision (like a prisim)
17. How are microscopes corrected for chromatic aberration?: With a special
achromat-
ic 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.
18. Describe the process of making a wet-mount slide: 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.
19. Describe the purpose of making a wet-mount slide: To be able to see living
organisms under the microscope in their natural state.
20. What is the advantage of using a wet-mount slide?: Can see movement and
determine if microbes posses their own method of motility. Can also see the actual
shape and arrangement of microbes.
21. What is the dis-advantage of using a wet-mount slide?: The movement is very fast,
microbes are transparent. Must use a "dark-field stop".
22. What is a producer?: Are autotroph organisms that make their own food (through
photosynthesis).
23. What structure is an indicator of a producer?: Chloroplasts is an indicator that an
organism is a producer.
24. An example of a producer is what?: Algae are producers that are found in a pond.
25. What is a consumer?: They are heterotrophic organisms that get their food from
another source (nonphotosynthetic)
26. Examples of a consumer are what?: Protozoans such as paramecium and
multicellular animals like rotifers or daphnia.
27. What is osmosis?: The diffusion of water
MICROBIOLOGY LAB EXAM QUESTIONS AND
ANSWERS VERIFIED
1.Microscope- The Condenser: focuses the light ging into the objective lens
2.Microscope- The Iris Diaphragm: adjusts the amount of light going into the objective
lens
3.Microscope- Nosepiece: holds the objective lenses and rotates to change from one
objective to another 4. Microscope- Coarse Objective Knob: moves the stage larger
distances to help get the object in focus
5.Microscope- Fine Adjustment Knob: moves the stage smaler increments to help get the
object in better focus
6.Microscope- Objective Lens: magnifies the object. It is located near the object.
7.Microscope- Occular Lens: magnifies the image of the object from the objective lens. It
is located near the eye.
8.Steps in using the microscope: 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
9. Describe the purpose of the oil immersion lens: Used when oil is added to the slide.
Oil must touch the object and objective lens to that the light does not refract futher
10. Parfocal: 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
11. Resolution: The ability to distinguish between two objects that are very close
together.
12. What is resolving power?: The measurement of resolution
13. What are two ways to increase resolving power?: 1. By decreasing the wavelength
of light
(using a blue filter) 2. Increasing the numerical aperature
, 14. What units are used to express resolving power?: nm or nanometers
15. What is better, smaller or larger resolving power?: Smaller is better
Light microscopes have a 200nm resolving power
Electron microscopes have a .2nm resolving power
16. What is chromatic aberration?: The effect when many colors are seen toward the
edge of the microscope field of vision (like a prisim)
17. How are microscopes corrected for chromatic aberration?: With a special
achromat-
ic 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.
18. Describe the process of making a wet-mount slide: 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.
19. Describe the purpose of making a wet-mount slide: To be able to see living
organisms under the microscope in their natural state.
20. What is the advantage of using a wet-mount slide?: Can see movement and
determine if microbes posses their own method of motility. Can also see the actual
shape and arrangement of microbes.
21. What is the dis-advantage of using a wet-mount slide?: The movement is very fast,
microbes are transparent. Must use a "dark-field stop".
22. What is a producer?: Are autotroph organisms that make their own food (through
photosynthesis).
23. What structure is an indicator of a producer?: Chloroplasts is an indicator that an
organism is a producer.
24. An example of a producer is what?: Algae are producers that are found in a pond.
25. What is a consumer?: They are heterotrophic organisms that get their food from
another source (nonphotosynthetic)
26. Examples of a consumer are what?: Protozoans such as paramecium and
multicellular animals like rotifers or daphnia.
27. What is osmosis?: The diffusion of water
