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Microbio 150 Lab exam 1 PVCC Exam Questions
and Answers 100% Pass
When preparing to view a specimen on a compound microscope in the lab, one should __________ begin
with the 4x objective - ✔✔Always
Where should used gloves be disposed of in the microbiology lab - ✔✔In the bio-hazard waste container
Before putting a dust cover over the microscope and placing it in the cabinet, which objective lens should
be rotated over the stage - ✔✔4x
On the microscope, what concentrates the light on the specimen? - ✔✔Condenser lens
On the microscope, what bends light passing through the specimen to create a real image - ✔✔Objective
lens
On the microscope, what allows for more or less light to be directed onto the specimen - ✔✔Iris
diaphragm
On the microscope, what gives you clarity of the image - ✔✔Resolution
Why is desiccating your inoculating loop important? When should this be done? - ✔✔To ensure it is
sterilized, done so no cross contamination happens
During an aseptic transfer, when do you pass the mouth of the test tube through the flame? - ✔✔Before
and after dipping loop in
During the broth to slide aseptic transfer, a __________ was used to obtain a pure culture from a
__________. - ✔✔Loop, broth
Created by Katelyn Whitman © 2025, All Rights Reserved. 100% PASS GUARANTEE
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Prior to staining, smears of microorganisms are heat-fixed in order to - ✔✔Attach it firmly to the slide
The term that refers to the purposeful addition of microorganisms into a nutrient medium is -
✔✔Inoculation
True or false: In the microbiology lab, it is acceptable to move your loop around while waiting for it to
dry. - ✔✔False
Which stain was used during the negative staining procedure? - ✔✔Nigrosin
Which stain was used during the simple staining procedure? - ✔✔Methylene blue
True or false: During a negative stain, the bacteria are heat fixed. - ✔✔False
Bacteria in the Mycobacterium genus have the presence of what component in the cell wall that causes
them to be acid-fast? - ✔✔Peptidoglycan
After the decolorizer has been added, gram-positive organisms appear __________ and gram-negative
organisms appear __________. - ✔✔Purple; colorless
Why is iodine (or a mordant) used in the Gram staining process? - ✔✔It forms a complex with crystal
violet
True or false: bacterial slides are not heat-fixed prior to beginning to Gram staining. - ✔✔False
When completing a bacterial transfer from a broth, where should the cap be located while you are
inserting your inoculating instrument in the bacterial growth? - ✔✔The cap should be held in the pinky
of your dominant hand
- ✔✔Agar slant
- ✔✔Broth tube
- ✔✔Agar plate
Created by Katelyn Whitman © 2025, All Rights Reserved. 100% PASS GUARANTEE
Microbio 150 Lab exam 1 PVCC Exam Questions
and Answers 100% Pass
When preparing to view a specimen on a compound microscope in the lab, one should __________ begin
with the 4x objective - ✔✔Always
Where should used gloves be disposed of in the microbiology lab - ✔✔In the bio-hazard waste container
Before putting a dust cover over the microscope and placing it in the cabinet, which objective lens should
be rotated over the stage - ✔✔4x
On the microscope, what concentrates the light on the specimen? - ✔✔Condenser lens
On the microscope, what bends light passing through the specimen to create a real image - ✔✔Objective
lens
On the microscope, what allows for more or less light to be directed onto the specimen - ✔✔Iris
diaphragm
On the microscope, what gives you clarity of the image - ✔✔Resolution
Why is desiccating your inoculating loop important? When should this be done? - ✔✔To ensure it is
sterilized, done so no cross contamination happens
During an aseptic transfer, when do you pass the mouth of the test tube through the flame? - ✔✔Before
and after dipping loop in
During the broth to slide aseptic transfer, a __________ was used to obtain a pure culture from a
__________. - ✔✔Loop, broth
Created by Katelyn Whitman © 2025, All Rights Reserved. 100% PASS GUARANTEE
, 2|Page
Prior to staining, smears of microorganisms are heat-fixed in order to - ✔✔Attach it firmly to the slide
The term that refers to the purposeful addition of microorganisms into a nutrient medium is -
✔✔Inoculation
True or false: In the microbiology lab, it is acceptable to move your loop around while waiting for it to
dry. - ✔✔False
Which stain was used during the negative staining procedure? - ✔✔Nigrosin
Which stain was used during the simple staining procedure? - ✔✔Methylene blue
True or false: During a negative stain, the bacteria are heat fixed. - ✔✔False
Bacteria in the Mycobacterium genus have the presence of what component in the cell wall that causes
them to be acid-fast? - ✔✔Peptidoglycan
After the decolorizer has been added, gram-positive organisms appear __________ and gram-negative
organisms appear __________. - ✔✔Purple; colorless
Why is iodine (or a mordant) used in the Gram staining process? - ✔✔It forms a complex with crystal
violet
True or false: bacterial slides are not heat-fixed prior to beginning to Gram staining. - ✔✔False
When completing a bacterial transfer from a broth, where should the cap be located while you are
inserting your inoculating instrument in the bacterial growth? - ✔✔The cap should be held in the pinky
of your dominant hand
- ✔✔Agar slant
- ✔✔Broth tube
- ✔✔Agar plate
Created by Katelyn Whitman © 2025, All Rights Reserved. 100% PASS GUARANTEE
