Microbiology LAB Exam #1(Exam over
Labs 1-10)2023
Microscope- The Condenser - Answer focuses the light ging into the objective lens
Microscope- The Iris Diaphragm - Answer adjusts the amount of light going into the
objective lens
Microscope- Nosepiece - Answer holds the objective lenses and rotates to change
from one objective to another
Microscope- Coarse Objective Knob - Answer moves the stage larger distances to
help get the object in focus
Microscope- Fine Adjustment Knob - Answer moves the stage smaler increments to
help get the object in better focus
Microscope- Objective Lens - Answer magnifies the object. It is located near the
object.
Microscope- Occular Lens - Answer magnifies the image of the object from the
objective lens. It is located near the eye.
Steps in using the microscope - 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 - 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 - 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 - Answer The ability to distinguish between two objects that are very
close together.
What is resolving power? - Answer The measurement of resolution
What are two ways to increase resolving power? - 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? - Answer nm or nanometers
What is better, smaller or larger resolving power? - Answer Smaller is better
Light microscopes have a 200nm resolving power
Electron microscopes have a .2nm resolving power
, Microbiology LAB Exam #1(Exam over
Labs 1-10)2023
What is chromatic aberration? - 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? - 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 - 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 - 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? - Answer 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? - Answer The movement is
very fast, microbes are transparent. Must use a "dark-field stop".
What is a producer? - Answer Are autotroph organisms that make their own food
(through photosynthesis).
What structure is an indicator of a producer? - Answer Chloroplasts is an indicator
that an organism is a producer.
An example of a producer is what? - Answer Algae are producers that are found in a
pond.
What is a consumer? - Answer They are heterotrophic organisms that get their food
from another source (nonphotosynthetic)
Examples of a consumer are what? - Answer Protozoans such as paramecium and
multicellular animals like rotifers or daphnia.
What is osmosis? - Answer The diffusion of water
What organelle of protozoans responds to osmosis? - Answer The cell membrane is
where diffusion occurs.
Why do we use asephtic technique of bacteria? - Answer To obtain pure cultures
and to prevent contamination of pure cultures.
When is it best to use a broth? - Answer When you want to grow a lot of bacteria.
Labs 1-10)2023
Microscope- The Condenser - Answer focuses the light ging into the objective lens
Microscope- The Iris Diaphragm - Answer adjusts the amount of light going into the
objective lens
Microscope- Nosepiece - Answer holds the objective lenses and rotates to change
from one objective to another
Microscope- Coarse Objective Knob - Answer moves the stage larger distances to
help get the object in focus
Microscope- Fine Adjustment Knob - Answer moves the stage smaler increments to
help get the object in better focus
Microscope- Objective Lens - Answer magnifies the object. It is located near the
object.
Microscope- Occular Lens - Answer magnifies the image of the object from the
objective lens. It is located near the eye.
Steps in using the microscope - 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 - 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 - 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 - Answer The ability to distinguish between two objects that are very
close together.
What is resolving power? - Answer The measurement of resolution
What are two ways to increase resolving power? - 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? - Answer nm or nanometers
What is better, smaller or larger resolving power? - Answer Smaller is better
Light microscopes have a 200nm resolving power
Electron microscopes have a .2nm resolving power
, Microbiology LAB Exam #1(Exam over
Labs 1-10)2023
What is chromatic aberration? - 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? - 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 - 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 - 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? - Answer 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? - Answer The movement is
very fast, microbes are transparent. Must use a "dark-field stop".
What is a producer? - Answer Are autotroph organisms that make their own food
(through photosynthesis).
What structure is an indicator of a producer? - Answer Chloroplasts is an indicator
that an organism is a producer.
An example of a producer is what? - Answer Algae are producers that are found in a
pond.
What is a consumer? - Answer They are heterotrophic organisms that get their food
from another source (nonphotosynthetic)
Examples of a consumer are what? - Answer Protozoans such as paramecium and
multicellular animals like rotifers or daphnia.
What is osmosis? - Answer The diffusion of water
What organelle of protozoans responds to osmosis? - Answer The cell membrane is
where diffusion occurs.
Why do we use asephtic technique of bacteria? - Answer To obtain pure cultures
and to prevent contamination of pure cultures.
When is it best to use a broth? - Answer When you want to grow a lot of bacteria.
