“Lab 2 Culturing & Aseptic Technique BIO250L”
Student Name: Click here to enter text.
Access Code (located on the underside of the lid of your lab kit): Click here to enter text.
“Pre-Lab Questions”
1. Proper aseptic technique is crucial to ensuring growth of pure bacterial colonies. What is one
experimental way you can test your practices to confirm that you are using proper aseptic
technique?
In order to attain pure bacterial colonies we need to make sure that the
aseptic technique used was flawless. We can test this by leaving a
“control”. After the preparation of sterile media, we spare a portion that will
not be inoculated. Both samples – inoculated and not – will be incubated. If
the aseptic technique was correct, the control will not have bacterial
colonies.
2. In a laboratory setting, what are three ways you can properly sterilize culturing equipment?
a. One popular way to sterilize culturing equipment is wet heat –
autoclaving.
b. Another way can be dry heat.
c. Another method used in sterilizing is radiation.
3. For each inoculation tool, give one scenario in which use of that tool would be appropriate.
Autoclaving can be used to decontaminate lab ware and instruments –
, “Lab 2 Culturing & Aseptic Technique BIO250L”
excluding flammable or reactive objects and substances. Dry heat can be
used for hydrophobic materials (fats and oils) – such as powders.
Radiation can be used in sterilization of surgical gloves.
4. Why don’t microorganisms in cultures exhibit constant exponential growth? What are some
steps you could take to extend the lifespan of a microbial culture?
Microorganisms in cultures do no exhibit constant exponential growth
because of the limited space they are placed in and accumulation of waste
products. One way to extend the lifespan of microbial culture is through
subculturing – transferring the microorganism to new media to favor their
growth while also ensuring the proper amount of nutrients.
5. Using a textbook or a reputable online source, describe how lab cultures are maintained in a
continual pattern of growth. Focus particularly on those used in biotechnology, such as E. coli,
which is used to make human insulin.
According to the article Continuous culture of Escherichia coli, under
selective pressure by a novel antimicrobial complex, does not result in
development of resistance, written by Tonoyan, L., Fleming, G.T.A., Friel,
R. et al. , lab cultures of E.coli are maintained in a continual pattern of growth
by adding fresh media continuously in a chemostat vessel, while also
eliminating the waste culture. This pattern of growth can be used in
application such as testing the resistance/sensibility of microorganisms to
antibiotics.
Student Name: Click here to enter text.
Access Code (located on the underside of the lid of your lab kit): Click here to enter text.
“Pre-Lab Questions”
1. Proper aseptic technique is crucial to ensuring growth of pure bacterial colonies. What is one
experimental way you can test your practices to confirm that you are using proper aseptic
technique?
In order to attain pure bacterial colonies we need to make sure that the
aseptic technique used was flawless. We can test this by leaving a
“control”. After the preparation of sterile media, we spare a portion that will
not be inoculated. Both samples – inoculated and not – will be incubated. If
the aseptic technique was correct, the control will not have bacterial
colonies.
2. In a laboratory setting, what are three ways you can properly sterilize culturing equipment?
a. One popular way to sterilize culturing equipment is wet heat –
autoclaving.
b. Another way can be dry heat.
c. Another method used in sterilizing is radiation.
3. For each inoculation tool, give one scenario in which use of that tool would be appropriate.
Autoclaving can be used to decontaminate lab ware and instruments –
, “Lab 2 Culturing & Aseptic Technique BIO250L”
excluding flammable or reactive objects and substances. Dry heat can be
used for hydrophobic materials (fats and oils) – such as powders.
Radiation can be used in sterilization of surgical gloves.
4. Why don’t microorganisms in cultures exhibit constant exponential growth? What are some
steps you could take to extend the lifespan of a microbial culture?
Microorganisms in cultures do no exhibit constant exponential growth
because of the limited space they are placed in and accumulation of waste
products. One way to extend the lifespan of microbial culture is through
subculturing – transferring the microorganism to new media to favor their
growth while also ensuring the proper amount of nutrients.
5. Using a textbook or a reputable online source, describe how lab cultures are maintained in a
continual pattern of growth. Focus particularly on those used in biotechnology, such as E. coli,
which is used to make human insulin.
According to the article Continuous culture of Escherichia coli, under
selective pressure by a novel antimicrobial complex, does not result in
development of resistance, written by Tonoyan, L., Fleming, G.T.A., Friel,
R. et al. , lab cultures of E.coli are maintained in a continual pattern of growth
by adding fresh media continuously in a chemostat vessel, while also
eliminating the waste culture. This pattern of growth can be used in
application such as testing the resistance/sensibility of microorganisms to
antibiotics.
