MICROBIOLOGY LAB FINAL EXAM VERSION
1 2025/2026 WITH ACTUAL CORRECT
QUESTIONS AND VERIFIED DETAILED
ANSWERS |FREQUENTLY TESTED
QUESTIONS AND SOLUTIONS |ALREADY
GRADED A+|NEWEST|BRAND NEW
VERSION!!|LATEST UPDATE
What does it mean when the box of tips for the mechanical pipettes has a piece of autoclave
tape covering the opening?
Question options:
A)
It means that the box of tips has been sterilized in the autoclave, but someone has already
opened the box.
B)
It means that the box of tips has not yet been sterilized in the autoclave.
C)
It means that the box of tips has been sterilized in the autoclave, and has not yet been opened.
It means that the box of tips has been sterilized in the autoclave, and has not yet been opened.
What should you do if you are the first person to open a new box of tips for the mechanical
pipette?
Question options:
A)
You should remove the piece of autoclave tape from the box entirely and throw it in the
garbage. This tells other people that the tips absolutely not sterile anymore.
B)
You should remove the piece of tape briefly to take a tip, and then return it to the front of the
box as soon as you have one, so that the box doesn't look like its been disturbed.
C)
You should move the piece of autoclave tape from the front of the box to the top, to tell other
people that the box has been opened.
1|Page
,You should move the piece of autoclave tape from the front of the box to the top, to tell other
people that the box has been opened.
How should you discard a pipette tip after you have used it?
Question options:
A)
You should carefully remove the tip with your fingers, and then place it on the nearest glassware
discard trolley.
B)
You should remove the the used tips and place them neatly on your work bench. Once you're
done for the day, you can collect all the tips and discard them in the nearest waste paper
basket.
C)
You should simply reach over to the nearest sharps container, and depress the tip ejector button
so that the tip drops directly into the sharps waste bucket.
You should simply reach over to the nearest sharps container, and depress the tip ejector button
so that the tip drops directly into the sharps waste bucket.
To label a test tube, it's best to use a permanent marker and:
Question options:
A)
Write directly on the surface of the glass (but not on the white frosted area) to make clean-up
easy.
B)
Write on the white frosted area of the tube to make sure that your writing doesn't accidentally
get wiped away.
Write directly on the surface of the glass (but not on the white frosted area) to make clean-up
easy.
After transferring 1 ml from the first test tube, into the next test tube, with a P1000 mechanical
pipette, I should:
Question options:
A)
Keep my pipette in my hand being careful not to let the tip touch anything, mix the tube by
swirling vigorously in my other hand. After mixing, continue my serial dilution using the same
tip.
B)
Carefully place my pipette on top of something, like a test tube rack or the tip box so that the tip
2|Page
,doesn't touch anything, while I shake the tube up and down to mix it.
C)
Discard my pipette tip, place my pipette on the counter, mix the tube by tapping the bottom ten
times, and then get a fresh tip to continue my dilution series.
Discard my pipette tip, place my pipette on the counter, mix the tube by tapping the bottom ten
times, and then get a fresh tip to continue my dilution series.
When I am plating dilution tubes onto Petri plates, it's best to:
Question options:
A)
Lift the lid just enough so that I can reach underneath it to expel my sample onto the surface of
the agar.
B)
Leave the lid on the plate entirely, and pipette my sample onto the lid. Bacteria will grow fine
there.
C)
Remove the lid from the plate entirely and put it down on the counter top.
Lift the lid just enough so that I can reach underneath it to expel my sample onto the surface of
the agar.
When performing the spread plate technique, I should:
Question options:
A)
Hold the hockey stick flat against the surface of the plate, and spin the turntable to spread the
sample.
B)
Not even attempt to spread the plate. The properties of the Petri plate are such that the sample
should spread itself out over the surface while the plate is incubating.
C)
Spread the sample back and forth across the plate by wiggling the hockey stick with my hand.
Hold the hockey stick flat against the surface of the plate, and spin the turntable to spread the
sample.
To sterilize the glass spreader, I should:
Question options:
A)
Dip the spreader in alcohol for a few seconds, and then immediately pass the spreader through
the flame of the burner, before the alcohol has had a chance to drip off.
3|Page
, B)
Dip the spreader in alcohol for a few seconds, then try to shake off whatever excess alcohol I
can. Finally, I'll give the spreader a quick pass through the flame to burn off any remnants of
alcohol.
C)
Dip the spreader in alcohol for a few seconds, then try to shake off whatever excess alcohol I
can. Finally, I will hold the spreader in the flame for about 5 seconds, or until it turns red hot so
that I can be sure it has been sterilized.
Dip the spreader in alcohol for a few seconds, then try to shake off whatever excess alcohol I
can. Finally, I'll give the spreader a quick pass through the flame to burn off any remnants of
alcohol.
To make a smear for microscopy from a sample growing on a Petri plate, I should:
Question options:
A)
Touch a single colony with my needle, and mix it into a small drop of water on my microscope
slide. Let it air dry and then heat fix it over the pilot flame of the burner.
B)
Pick a single colony, by scooping the entire colony up with my loop, and then mix the entire
loopful into a drop of water on the slide until the mixture is thick and cloudy. Heat the slide
gently over the flame of the burner to both dry the slide and heat fix it, at the same time.
C)
Touch several colonies with my needle and then smear them across a dry microscope slide. Add
a drop of water and then heat fix over the pilot flame of the burner.
Touch a single colony with my needle, and mix it into a small drop of water on my microscope
slide. Let it air dry and then heat fix it over the pilot flame of the burner.
When staining, you will be reaching across your workstation to use the staining sink in the
middle of the bench. When you're reaching across your work station, it is best to:
Question options:
A)
Have the Bunsen burner turned on with the hot blue flame, and close at hand, in case you need
to sterilize something while you are staining.
B)
Have the Bunsen burner turned off entirely. If you need it again after your stain is finished, you
can always re-light it later.
C)
4|Page
1 2025/2026 WITH ACTUAL CORRECT
QUESTIONS AND VERIFIED DETAILED
ANSWERS |FREQUENTLY TESTED
QUESTIONS AND SOLUTIONS |ALREADY
GRADED A+|NEWEST|BRAND NEW
VERSION!!|LATEST UPDATE
What does it mean when the box of tips for the mechanical pipettes has a piece of autoclave
tape covering the opening?
Question options:
A)
It means that the box of tips has been sterilized in the autoclave, but someone has already
opened the box.
B)
It means that the box of tips has not yet been sterilized in the autoclave.
C)
It means that the box of tips has been sterilized in the autoclave, and has not yet been opened.
It means that the box of tips has been sterilized in the autoclave, and has not yet been opened.
What should you do if you are the first person to open a new box of tips for the mechanical
pipette?
Question options:
A)
You should remove the piece of autoclave tape from the box entirely and throw it in the
garbage. This tells other people that the tips absolutely not sterile anymore.
B)
You should remove the piece of tape briefly to take a tip, and then return it to the front of the
box as soon as you have one, so that the box doesn't look like its been disturbed.
C)
You should move the piece of autoclave tape from the front of the box to the top, to tell other
people that the box has been opened.
1|Page
,You should move the piece of autoclave tape from the front of the box to the top, to tell other
people that the box has been opened.
How should you discard a pipette tip after you have used it?
Question options:
A)
You should carefully remove the tip with your fingers, and then place it on the nearest glassware
discard trolley.
B)
You should remove the the used tips and place them neatly on your work bench. Once you're
done for the day, you can collect all the tips and discard them in the nearest waste paper
basket.
C)
You should simply reach over to the nearest sharps container, and depress the tip ejector button
so that the tip drops directly into the sharps waste bucket.
You should simply reach over to the nearest sharps container, and depress the tip ejector button
so that the tip drops directly into the sharps waste bucket.
To label a test tube, it's best to use a permanent marker and:
Question options:
A)
Write directly on the surface of the glass (but not on the white frosted area) to make clean-up
easy.
B)
Write on the white frosted area of the tube to make sure that your writing doesn't accidentally
get wiped away.
Write directly on the surface of the glass (but not on the white frosted area) to make clean-up
easy.
After transferring 1 ml from the first test tube, into the next test tube, with a P1000 mechanical
pipette, I should:
Question options:
A)
Keep my pipette in my hand being careful not to let the tip touch anything, mix the tube by
swirling vigorously in my other hand. After mixing, continue my serial dilution using the same
tip.
B)
Carefully place my pipette on top of something, like a test tube rack or the tip box so that the tip
2|Page
,doesn't touch anything, while I shake the tube up and down to mix it.
C)
Discard my pipette tip, place my pipette on the counter, mix the tube by tapping the bottom ten
times, and then get a fresh tip to continue my dilution series.
Discard my pipette tip, place my pipette on the counter, mix the tube by tapping the bottom ten
times, and then get a fresh tip to continue my dilution series.
When I am plating dilution tubes onto Petri plates, it's best to:
Question options:
A)
Lift the lid just enough so that I can reach underneath it to expel my sample onto the surface of
the agar.
B)
Leave the lid on the plate entirely, and pipette my sample onto the lid. Bacteria will grow fine
there.
C)
Remove the lid from the plate entirely and put it down on the counter top.
Lift the lid just enough so that I can reach underneath it to expel my sample onto the surface of
the agar.
When performing the spread plate technique, I should:
Question options:
A)
Hold the hockey stick flat against the surface of the plate, and spin the turntable to spread the
sample.
B)
Not even attempt to spread the plate. The properties of the Petri plate are such that the sample
should spread itself out over the surface while the plate is incubating.
C)
Spread the sample back and forth across the plate by wiggling the hockey stick with my hand.
Hold the hockey stick flat against the surface of the plate, and spin the turntable to spread the
sample.
To sterilize the glass spreader, I should:
Question options:
A)
Dip the spreader in alcohol for a few seconds, and then immediately pass the spreader through
the flame of the burner, before the alcohol has had a chance to drip off.
3|Page
, B)
Dip the spreader in alcohol for a few seconds, then try to shake off whatever excess alcohol I
can. Finally, I'll give the spreader a quick pass through the flame to burn off any remnants of
alcohol.
C)
Dip the spreader in alcohol for a few seconds, then try to shake off whatever excess alcohol I
can. Finally, I will hold the spreader in the flame for about 5 seconds, or until it turns red hot so
that I can be sure it has been sterilized.
Dip the spreader in alcohol for a few seconds, then try to shake off whatever excess alcohol I
can. Finally, I'll give the spreader a quick pass through the flame to burn off any remnants of
alcohol.
To make a smear for microscopy from a sample growing on a Petri plate, I should:
Question options:
A)
Touch a single colony with my needle, and mix it into a small drop of water on my microscope
slide. Let it air dry and then heat fix it over the pilot flame of the burner.
B)
Pick a single colony, by scooping the entire colony up with my loop, and then mix the entire
loopful into a drop of water on the slide until the mixture is thick and cloudy. Heat the slide
gently over the flame of the burner to both dry the slide and heat fix it, at the same time.
C)
Touch several colonies with my needle and then smear them across a dry microscope slide. Add
a drop of water and then heat fix over the pilot flame of the burner.
Touch a single colony with my needle, and mix it into a small drop of water on my microscope
slide. Let it air dry and then heat fix it over the pilot flame of the burner.
When staining, you will be reaching across your workstation to use the staining sink in the
middle of the bench. When you're reaching across your work station, it is best to:
Question options:
A)
Have the Bunsen burner turned on with the hot blue flame, and close at hand, in case you need
to sterilize something while you are staining.
B)
Have the Bunsen burner turned off entirely. If you need it again after your stain is finished, you
can always re-light it later.
C)
4|Page
