Microbiology Lab Practical 1 (TAMUCC)-
Questions & Answers
How is total magnification calculated? Correct Ans-Multiply the ocular lens (10x) by the
objective lens
10x*10=100x
40x*10=400x
100x*10=1000x
OCULAR TIME OBJECTIVE
what is the function of immersion oil when using the oil immersion objective? Correct Ans-
the immersion oil allows for magnification and increases the contrast of the specimen
What is meant by the term parfocal? Correct Ans-Once the lens is focused on a particular area
it will remain focused on the particular area regardless of changing the objective
why aren't the magnifications of both lenses of binocular microscope used to calculate total
magnification? Correct Ans-Because the image only goes through one ocular to reach both
eyes
Why is the 10x placed in position when the microscope is stored or carried? Correct Ans-The
low-power objective is farther away from the stage than the other objectives so the lens is less
likely to get scrapped during handling.
, What is an aseptic technique? What is its importance? Why do you always have to do it in the
microbiology lab? Correct Ans--Microbiologists use aseptic technique for a variety of
procedures such as transferring cultures, inoculating media, isolation of pure cultures, and for
performing microbiological tests.
-Proper aseptic technique prevents contamination of cultures from foreign bacteria inherent in
the environment.
what are some aseptic techniques used when transfering cultures from plate to broth tube and
agar slant? Correct Ans-1. Prepare your desktop by swabbing down its surface with a
disinfectant.
2. Wash your hands
3. With a marking pen, label a tube of sterile nutrient broth with name, date and specimen
4. Sterilize the inoculating loop by holding it over the flame of a Bunsen burner until it becomes
bright red. The entire wire must be heated.
what is a culture medium? Correct Ans-An artificial environment that provides water and
nutrients for the microorganism
Types of culture media used in the lab based on form Correct Ans-NA (Agar) Slant: solid at
50C or above, if below liquid
NB tubes: liquid, cloudy, yellow
NA Agar Plate: solid cloudy yellow
What is pure culture? Correct Ans-population of cells derived from a single cell
Questions & Answers
How is total magnification calculated? Correct Ans-Multiply the ocular lens (10x) by the
objective lens
10x*10=100x
40x*10=400x
100x*10=1000x
OCULAR TIME OBJECTIVE
what is the function of immersion oil when using the oil immersion objective? Correct Ans-
the immersion oil allows for magnification and increases the contrast of the specimen
What is meant by the term parfocal? Correct Ans-Once the lens is focused on a particular area
it will remain focused on the particular area regardless of changing the objective
why aren't the magnifications of both lenses of binocular microscope used to calculate total
magnification? Correct Ans-Because the image only goes through one ocular to reach both
eyes
Why is the 10x placed in position when the microscope is stored or carried? Correct Ans-The
low-power objective is farther away from the stage than the other objectives so the lens is less
likely to get scrapped during handling.
, What is an aseptic technique? What is its importance? Why do you always have to do it in the
microbiology lab? Correct Ans--Microbiologists use aseptic technique for a variety of
procedures such as transferring cultures, inoculating media, isolation of pure cultures, and for
performing microbiological tests.
-Proper aseptic technique prevents contamination of cultures from foreign bacteria inherent in
the environment.
what are some aseptic techniques used when transfering cultures from plate to broth tube and
agar slant? Correct Ans-1. Prepare your desktop by swabbing down its surface with a
disinfectant.
2. Wash your hands
3. With a marking pen, label a tube of sterile nutrient broth with name, date and specimen
4. Sterilize the inoculating loop by holding it over the flame of a Bunsen burner until it becomes
bright red. The entire wire must be heated.
what is a culture medium? Correct Ans-An artificial environment that provides water and
nutrients for the microorganism
Types of culture media used in the lab based on form Correct Ans-NA (Agar) Slant: solid at
50C or above, if below liquid
NB tubes: liquid, cloudy, yellow
NA Agar Plate: solid cloudy yellow
What is pure culture? Correct Ans-population of cells derived from a single cell
