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
... [Show More] that you
are using proper aseptic technique?This could be done by having a control agar
plate where sterile loop was used to streak the agar. If it grows bacterial colonies after
some time, then aseptic technique was not successful.
2. In a laboratory setting, what are three ways you can properly sterilize culturing
equipment?
a. Dry heat
b. Wet heat
c. UV radiation
3. For each inoculation tool, give one scenario in which use of that tool would be
appropriate.Inoculation loops: used to collect inoculum from cultures; use when
transferring microbes from one plate to anotherSterile cotton swabs: to collect
microbial samples directly from different surfaces; use when beginning a culture plate in
microbio lab.Inoculation needles: to collect microbes from a defined region of a culture
and transfer to another medium or container; use to inoculate semisolid media or stab
tubesSterile plate spreaders: to inoculate plates using the spread plate method which
“Lab 2 Culturing & Aseptic Technique BIO250L”
evenly distributes microbial colonies on the media; spreading arm creates a bacterial
lawn by distributing a liquid sample evenly on the grow plate.
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?
This is because nutrients for the microorganisms run out, they are poisoned by waste
buildup, or alter their environment pH which would prevent them from replicating.
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.In order
to maintain lab cultures in a continual pattern of growth, the colonies must be provided
with more growth medium, which is done by transferring them to a new plate or replacing
the liquid medium. Continuous culture can be maintained in a device called a chemostat
(Jannasch & Mateles, 1974). This is done by continually adding fresh medium to the
growing culture and removing culture at a rate that eventually, the culture reaches a
steady-state where the microorganisms grow continuously at a constant rate and the
growth rate of the population is equal to the rate at which it is diluted (Gresham &
Dunham, 2014).Jannasch, H. W., & Mateles, R. I. (1974). Experimental bacterial ecology
studied in continuous culture. In Advances in Microbial Physiology (Vol. 11, pp. 165-
212). Academic Press.Gresham, D., & Dunham, M. J. (2014). The enduring utility of [Show Less]