Microbiology lab Practical review eXaM 2026 witH correct
actUal QUeStioNS aND correctly well DeFiNeD aNSwerS lateSt
alreaDy graDeD a+
How do you do a Gram stain? - aNSwer-1. Draw circles on slide
2. Spread microbes inside circles --> wait until dry
3. Heat fix
4. Crystal violet - 1min
5. Gram's Iodine - 1min
6. alcohol - 5 seconds --> wash immediately with water
7. safranin - 1-2mins
8. Rise with water
9. Blot (GENTLY)
what is the difference between sterilization and aseptic - aNSwer-Sterilization is the
destruction or removal of all viable microorganisms. Aseptic is the absence of unwanted
microorganisms
List six aseptic technique procedures - aNSwer-1. Keep unnecessary material off your
work area
2. disinfect the bench top
3. flame sterilize loop/needle
4. do not lay caps on bench tops
5. flame lips of tubes
6. aseptically transfer material
7. re-flame lip of tube
8. cover petri dishes as completely as possible
9. disinfect bench top at end of session
10. wash hands before and after lab
, pathogenic infections - aNSwer-infection caused by a disease causing microorganism
nosocomial - aNSwer-infection that's hospital acquired
name two ways to check if you have a pure culture - aNSwer-streak plate and Gram
stain
what's the difference between a simple and differential stain - aNSwer-simple stain uses
only one stain and only colors cells so they may be easily observed for size, shape, and
arrangement. differential stain uses more than one stain and selectively emphasizes
certain cell parts
When looking at an endospore stain, what color indicates a Gram positive bacteria? How
about Gram negative bacteria? - aNSwer-Endospore stain only tests for presence or
absence of endospores. You van't tell Gram reaction from an endospore stain.
Determine the actual size of the specimen. Convert final answer to micrometers
1. observed size 1.46 mm
2. you are using the 100x objective - aNSwer-Total magnification = 10x100= 1000 times
1) 1.46 mm/ 1000 1.46x10^-3 mm
2) 1.46x10^-3 (1000/1mm) = 1.46 micrometers
Determine the observed size of the object
1. Actual size = 3.7 micrometers
2. you are using the 4x objective - aNSwer-Total magnification = 10x4 = 40 times
1) 3.7 micrometers x 40 = 148 micrometers
2) 148 (1mm/1000micrometers) = 1.48x10^-1
parts of a microscope - aNSwer-
actUal QUeStioNS aND correctly well DeFiNeD aNSwerS lateSt
alreaDy graDeD a+
How do you do a Gram stain? - aNSwer-1. Draw circles on slide
2. Spread microbes inside circles --> wait until dry
3. Heat fix
4. Crystal violet - 1min
5. Gram's Iodine - 1min
6. alcohol - 5 seconds --> wash immediately with water
7. safranin - 1-2mins
8. Rise with water
9. Blot (GENTLY)
what is the difference between sterilization and aseptic - aNSwer-Sterilization is the
destruction or removal of all viable microorganisms. Aseptic is the absence of unwanted
microorganisms
List six aseptic technique procedures - aNSwer-1. Keep unnecessary material off your
work area
2. disinfect the bench top
3. flame sterilize loop/needle
4. do not lay caps on bench tops
5. flame lips of tubes
6. aseptically transfer material
7. re-flame lip of tube
8. cover petri dishes as completely as possible
9. disinfect bench top at end of session
10. wash hands before and after lab
, pathogenic infections - aNSwer-infection caused by a disease causing microorganism
nosocomial - aNSwer-infection that's hospital acquired
name two ways to check if you have a pure culture - aNSwer-streak plate and Gram
stain
what's the difference between a simple and differential stain - aNSwer-simple stain uses
only one stain and only colors cells so they may be easily observed for size, shape, and
arrangement. differential stain uses more than one stain and selectively emphasizes
certain cell parts
When looking at an endospore stain, what color indicates a Gram positive bacteria? How
about Gram negative bacteria? - aNSwer-Endospore stain only tests for presence or
absence of endospores. You van't tell Gram reaction from an endospore stain.
Determine the actual size of the specimen. Convert final answer to micrometers
1. observed size 1.46 mm
2. you are using the 100x objective - aNSwer-Total magnification = 10x100= 1000 times
1) 1.46 mm/ 1000 1.46x10^-3 mm
2) 1.46x10^-3 (1000/1mm) = 1.46 micrometers
Determine the observed size of the object
1. Actual size = 3.7 micrometers
2. you are using the 4x objective - aNSwer-Total magnification = 10x4 = 40 times
1) 3.7 micrometers x 40 = 148 micrometers
2) 148 (1mm/1000micrometers) = 1.48x10^-1
parts of a microscope - aNSwer-
