BI 234 LAB PRACTICAL 1 EXAM QUESTIONS AND
ANSWERS WITH COMPLETE SOLUTIONS VERIFIED
aseptic technique
Purpose is to maintain pure culture by avoiding cross contamination & to avoid
contaminating lab environment.
aseptic technique fails
if you contaminate it with unknown bacterium because you can not determine which
microbe is responsible for the reaction you observe. It is to protect you & classmates
from organisms that could cause disease.
Quadrant streak plate technique
Purpose: isolate bacterial colonies on the surface of agar plate.
Quadrant method is used for
1. Determine the colony morphology of bacterium.
2. determine whether a culture contains only one type of bacterium.
3. obtain pure culture of a bacterium.
Quadrant fails if
you get too much media on the plate
forgot to flame the loop or if you swipe media from 1st section into 4th.
colony morphology purpose
A colony is a group of bacteria all from the same parent cell, growing on a solid
medium.
Colony morphology observations
, 1. Shape
2. Margin
3. Surface appearance
4. Elevation
5. Opacity
6. Pigmentation
Tryptic Soy Agar (TSA slant)
used to grow and maintain your culture once isolated and identified pure colonies on
TSA plate.
Advantages to TSA slant
1. increased ability to maintain sterility
2. less media is used
3. decreased drying out for long-term storage as it can be capped.
TSA Selective & Differential
Selective media: favor media, manipulation of environment to encourage growth
Differential growth: Metabolism of bacteria. (change in color)
Benefits of TSA slant
saves money, small amounts of bacterium are used & helps with the risk of getting
contaminants.
Wet mount purpose
helps identify shape, motility and possibly size. It can't determine gram + or gram - and
brownian motion can complicate this observation.
Wet mount is made by
ANSWERS WITH COMPLETE SOLUTIONS VERIFIED
aseptic technique
Purpose is to maintain pure culture by avoiding cross contamination & to avoid
contaminating lab environment.
aseptic technique fails
if you contaminate it with unknown bacterium because you can not determine which
microbe is responsible for the reaction you observe. It is to protect you & classmates
from organisms that could cause disease.
Quadrant streak plate technique
Purpose: isolate bacterial colonies on the surface of agar plate.
Quadrant method is used for
1. Determine the colony morphology of bacterium.
2. determine whether a culture contains only one type of bacterium.
3. obtain pure culture of a bacterium.
Quadrant fails if
you get too much media on the plate
forgot to flame the loop or if you swipe media from 1st section into 4th.
colony morphology purpose
A colony is a group of bacteria all from the same parent cell, growing on a solid
medium.
Colony morphology observations
, 1. Shape
2. Margin
3. Surface appearance
4. Elevation
5. Opacity
6. Pigmentation
Tryptic Soy Agar (TSA slant)
used to grow and maintain your culture once isolated and identified pure colonies on
TSA plate.
Advantages to TSA slant
1. increased ability to maintain sterility
2. less media is used
3. decreased drying out for long-term storage as it can be capped.
TSA Selective & Differential
Selective media: favor media, manipulation of environment to encourage growth
Differential growth: Metabolism of bacteria. (change in color)
Benefits of TSA slant
saves money, small amounts of bacterium are used & helps with the risk of getting
contaminants.
Wet mount purpose
helps identify shape, motility and possibly size. It can't determine gram + or gram - and
brownian motion can complicate this observation.
Wet mount is made by
