Microbiology 2420: Lab Final Exam
and All Actual Answers.
What do you in case of spills or breakage? - Answer Immediately inform your laboratory
instructor or quarantine the area and wait for cleanup as instructed.
All labels must contain? - Answer Initials ( all 3) & section number BMS L4
date 04/18/2018
medium or test NA(nutrient)
name of organism ( or source of culture) E. coli
What is light microscopy? - Answer Light microscopy utilizes lenses, typically produced from
glass, to focus and magnify light rays passing through or reflected from a specimen.
How do you calculate the total magnification of a compound microscope? - Answer The total
magnification of a compound microscope is calculated by multiplying the power of the ocular
lens( eyepiece ) times the power of the objective lens( the one nearest the specimen).
Ocular lenses magnification ? - Answer 10x
Resolution( resolving power) - Answer the minimum distance between 2 points that allows
them to be distinguishable as 2 separate points.
What is the use of the sub-stage condenser? - Answer the use of a sub stage condenser and
the use of immersion oil at high magnification helps gather light to improve resolution.
How do you store a microscope? - Answer - the cord should be secured and folded
- high power objective ( blue one) in place
- stage all the way down
- rheostat turned to the lowest setting ( proper positioning of the rheostat increases the life of
the bulbs)
- free of oil, stains and dirt( leaving oil on the lenses will damage them)
How do clean your lenses on a microscope? - Answer Clean your lenses with ONLY lens
paper.
scanner objective lens - Answer magnification = 4x
,magnification ocular = 10x
total magnification = 40x
low power lens - Answer magnification = 10x
magnification ocular = 10x
total magnification = 100x
high power/ dry lens - Answer magnification= 40x
magnification ocular = 10x
total magnification = 400x
oil immersion lens - Answer magnification = 100x
magnification ocular = 10x
total magnification = 1000x
Major rules for the microscope? - Answer - mind the rheostat
- No course focus knob on high power
- DO NOT get oil on the high/ dry power lens
What is the lever of the iris diaphragm used for ? - Answer used to control the amount of
light reaching the specimen
- should be nearly closed on low power
- should be fully open on oil immersion
Coarse adjustment knob - Answer used to obtain initial focus ( never use on when using high
dry or oil immersion lenses)
Fine adjustment knob - Answer Used to sharpen focus.
How many times should one turn the fine adjustment knob? - Answer two full turns
Why is is incorrect to turn it more then this? - Answer It will override the stage stop
mechanism and the objective lens may hit the slide.
Parfocaling - Answer the ability to remain at or near focus when switching from one
objective lens to another.
, How does one properly parfocal? - Answer Center , adjust the light and fine focus.
one thing to remember about oil immersion - Answer Never touch the course adjustment on
oil immersion.
Before switching to a higher power objective lens, what must the position of the specimen be? -
Answer Centered
After adding oil, switching the oil immersion objective into place , and fine adjustment , the
image of the specimen cannot be visualized. Describe the procedure to get the image in focus
under oil immersion. - Answer 1) Rotate the nose piece past the scanning lens to the low
power , DO NOT GO PAST THE HIGH/DRY LENS
2) With the low power objective in place, reduce the light and use the course adjustment knob
to bring the object into focus and sharpen focus with the fine adjustment knob
3) Rotate the revolving nose piece in the opposite direction you turned it. Past the scanning lens
directing to the oil immersion lens.
4) Adjust the light and fine focus. Repeat if necessary.
Why do we use immersion oil ? - Answer Reduces light refraction
How do you label stock plates? - Answer -Label all plates on the bottoms with your wax
pencil (lids can be accidentally interchanged)
- Label in small letters, at the edge of the plates so your view of growing colonies will not be
obscured.
How do you label tubes? - Answer - Use only a small amount of tape ( no more than 1 inch)
- Affix the label below the closure but above the medium to allow viewing of specimen.
Growth media - Answer 1) liquid broth
2)solid - nutrient agar
How do you store a stock plate? - Answer Agar side up
Ubiquitous - Answer found everywhere , universal
Contamination - Answer Accidental , something that has escaped containment.
and All Actual Answers.
What do you in case of spills or breakage? - Answer Immediately inform your laboratory
instructor or quarantine the area and wait for cleanup as instructed.
All labels must contain? - Answer Initials ( all 3) & section number BMS L4
date 04/18/2018
medium or test NA(nutrient)
name of organism ( or source of culture) E. coli
What is light microscopy? - Answer Light microscopy utilizes lenses, typically produced from
glass, to focus and magnify light rays passing through or reflected from a specimen.
How do you calculate the total magnification of a compound microscope? - Answer The total
magnification of a compound microscope is calculated by multiplying the power of the ocular
lens( eyepiece ) times the power of the objective lens( the one nearest the specimen).
Ocular lenses magnification ? - Answer 10x
Resolution( resolving power) - Answer the minimum distance between 2 points that allows
them to be distinguishable as 2 separate points.
What is the use of the sub-stage condenser? - Answer the use of a sub stage condenser and
the use of immersion oil at high magnification helps gather light to improve resolution.
How do you store a microscope? - Answer - the cord should be secured and folded
- high power objective ( blue one) in place
- stage all the way down
- rheostat turned to the lowest setting ( proper positioning of the rheostat increases the life of
the bulbs)
- free of oil, stains and dirt( leaving oil on the lenses will damage them)
How do clean your lenses on a microscope? - Answer Clean your lenses with ONLY lens
paper.
scanner objective lens - Answer magnification = 4x
,magnification ocular = 10x
total magnification = 40x
low power lens - Answer magnification = 10x
magnification ocular = 10x
total magnification = 100x
high power/ dry lens - Answer magnification= 40x
magnification ocular = 10x
total magnification = 400x
oil immersion lens - Answer magnification = 100x
magnification ocular = 10x
total magnification = 1000x
Major rules for the microscope? - Answer - mind the rheostat
- No course focus knob on high power
- DO NOT get oil on the high/ dry power lens
What is the lever of the iris diaphragm used for ? - Answer used to control the amount of
light reaching the specimen
- should be nearly closed on low power
- should be fully open on oil immersion
Coarse adjustment knob - Answer used to obtain initial focus ( never use on when using high
dry or oil immersion lenses)
Fine adjustment knob - Answer Used to sharpen focus.
How many times should one turn the fine adjustment knob? - Answer two full turns
Why is is incorrect to turn it more then this? - Answer It will override the stage stop
mechanism and the objective lens may hit the slide.
Parfocaling - Answer the ability to remain at or near focus when switching from one
objective lens to another.
, How does one properly parfocal? - Answer Center , adjust the light and fine focus.
one thing to remember about oil immersion - Answer Never touch the course adjustment on
oil immersion.
Before switching to a higher power objective lens, what must the position of the specimen be? -
Answer Centered
After adding oil, switching the oil immersion objective into place , and fine adjustment , the
image of the specimen cannot be visualized. Describe the procedure to get the image in focus
under oil immersion. - Answer 1) Rotate the nose piece past the scanning lens to the low
power , DO NOT GO PAST THE HIGH/DRY LENS
2) With the low power objective in place, reduce the light and use the course adjustment knob
to bring the object into focus and sharpen focus with the fine adjustment knob
3) Rotate the revolving nose piece in the opposite direction you turned it. Past the scanning lens
directing to the oil immersion lens.
4) Adjust the light and fine focus. Repeat if necessary.
Why do we use immersion oil ? - Answer Reduces light refraction
How do you label stock plates? - Answer -Label all plates on the bottoms with your wax
pencil (lids can be accidentally interchanged)
- Label in small letters, at the edge of the plates so your view of growing colonies will not be
obscured.
How do you label tubes? - Answer - Use only a small amount of tape ( no more than 1 inch)
- Affix the label below the closure but above the medium to allow viewing of specimen.
Growth media - Answer 1) liquid broth
2)solid - nutrient agar
How do you store a stock plate? - Answer Agar side up
Ubiquitous - Answer found everywhere , universal
Contamination - Answer Accidental , something that has escaped containment.
