BMS 127 Lab Final Exam Questions With
Correct Answers
What is a colony of bacteria?
| | | | |
Group of individual bacteria living near each other
| | | | | | |
The mouth of a culture tube must be flamed after the closure is
| | | | | | | | | | | | |
removed and before it is replaced:
| | | | |
1. Why is this done?
| | | |
2. What happens when you flame the mouth of a glass culture tube?
| | | | | | | | | | | |
1. To prevent contaminants in the air from entering the tube
| | | | | | | | | |
2. It creates a convection current which forces air out of the tube
| | | | | | | | | | | |
What is a pure culture?
| | | |
Collection of microbial growth that contains only one species
| | | | | | | |
Why should your loop never be placed flat on the bench top?
| | | | | | | | | | |
,Contamination
Give 2 reasons why Petri dishes should be stored and incubated upside
| | | | | | | | | | | |
down
1. To avoid condensation build-up which could enter the agar
| | | | | | | | |
2. To prevent accidental exposure to and contamination of the culture
| | | | | | | | | | |
within
Why must your hand be held higher, not lower, than the portion of the
| | | | | | | | | | | | | |
loop being flamed?
| |
So that burning alcohol doesn't drip down your hand
| | | | | | | |
Name three things for which aseptic technique minimizes the risk of
| | | | | | | | | | |
contamination
Yourself, Your samples, your environment
| | | |
Give two reasons why agar makes a good growth surface for culturing
| | | | | | | | | | | |
bacteria
,1. It holds a lot of water and dissolved nutrients
| | | | | | | | |
2. Is indigestible to bacteria
| | | |
Why is it important to flame your loop between each streak in a streak
| | | | | | | | | | | | | |
isolation?
To destroy any remaining bacteria on it and effectively dilute the
| | | | | | | | | | |
concentration of bacteria | |
what would a streak isolation plate look like if the loop was not flamed
| | | | | | | | | | | | | |
in between each streak?
| | |
the bacteria were not isolated properly and you may find that the
| | | | | | | | | | | |
colonies in a later quadrant are larger than the bacteria in an earlier
| | | | | | | | | | | | |
quadrant
Agar is a gelatinous substance, mostly ___, derived from ___
| | | | | | | | |
polysaccharides; marine algae | |
Agar slant is made to increase the ___ on which the microorganisms will
| | | | | | | | | | | |
grow
|
, surface area |
If the agar in a culture tube is allowed to solidify with the tube upright,
| | | | | | | | | | | | | | |
the tube is called an ___
| | | | |
agar deep |
Petri dishes must always be stored ___
| | | | | |
upside down |
In order to correctly pipette a given volume, you must do three things:
| | | | | | | | | | | |
1. select the correct micropipette for the job
| | | | | | |
2. set the correct volume
| | | |
3. use the correct pipetting technique
| | | | |
Streak isolation is essentially a ___ performed on solid agar
| | | | | | | | |
dilution technique |
Correct Answers
What is a colony of bacteria?
| | | | |
Group of individual bacteria living near each other
| | | | | | |
The mouth of a culture tube must be flamed after the closure is
| | | | | | | | | | | | |
removed and before it is replaced:
| | | | |
1. Why is this done?
| | | |
2. What happens when you flame the mouth of a glass culture tube?
| | | | | | | | | | | |
1. To prevent contaminants in the air from entering the tube
| | | | | | | | | |
2. It creates a convection current which forces air out of the tube
| | | | | | | | | | | |
What is a pure culture?
| | | |
Collection of microbial growth that contains only one species
| | | | | | | |
Why should your loop never be placed flat on the bench top?
| | | | | | | | | | |
,Contamination
Give 2 reasons why Petri dishes should be stored and incubated upside
| | | | | | | | | | | |
down
1. To avoid condensation build-up which could enter the agar
| | | | | | | | |
2. To prevent accidental exposure to and contamination of the culture
| | | | | | | | | | |
within
Why must your hand be held higher, not lower, than the portion of the
| | | | | | | | | | | | | |
loop being flamed?
| |
So that burning alcohol doesn't drip down your hand
| | | | | | | |
Name three things for which aseptic technique minimizes the risk of
| | | | | | | | | | |
contamination
Yourself, Your samples, your environment
| | | |
Give two reasons why agar makes a good growth surface for culturing
| | | | | | | | | | | |
bacteria
,1. It holds a lot of water and dissolved nutrients
| | | | | | | | |
2. Is indigestible to bacteria
| | | |
Why is it important to flame your loop between each streak in a streak
| | | | | | | | | | | | | |
isolation?
To destroy any remaining bacteria on it and effectively dilute the
| | | | | | | | | | |
concentration of bacteria | |
what would a streak isolation plate look like if the loop was not flamed
| | | | | | | | | | | | | |
in between each streak?
| | |
the bacteria were not isolated properly and you may find that the
| | | | | | | | | | | |
colonies in a later quadrant are larger than the bacteria in an earlier
| | | | | | | | | | | | |
quadrant
Agar is a gelatinous substance, mostly ___, derived from ___
| | | | | | | | |
polysaccharides; marine algae | |
Agar slant is made to increase the ___ on which the microorganisms will
| | | | | | | | | | | |
grow
|
, surface area |
If the agar in a culture tube is allowed to solidify with the tube upright,
| | | | | | | | | | | | | | |
the tube is called an ___
| | | | |
agar deep |
Petri dishes must always be stored ___
| | | | | |
upside down |
In order to correctly pipette a given volume, you must do three things:
| | | | | | | | | | | |
1. select the correct micropipette for the job
| | | | | | |
2. set the correct volume
| | | |
3. use the correct pipetting technique
| | | | |
Streak isolation is essentially a ___ performed on solid agar
| | | | | | | | |
dilution technique |
