PreLab Assignment #6 Flashcards
What effect do UV rays have on bacterial growth and how does this happen?
a. The UV rays decrease bacterial growth, the light kills them preventing the growth
Do you think that wavelengths from the visible spectrum of light have the same effect as UV rays? Why or why not?
a. No I do not, wavelengths of light are not harmful to us and UV lights are. So this means that UV lights do more killing of bacteria so they do not have the same effect
There are many appliances available that utilize UV light to kill microorganisms on surfaces in operating rooms, airplane tray tables, grocery store aisles, etc. Based on what you have learned, do you think they work? Explain.
a. Yes, I do think that they work. The UV light kills the bacterial growth this would mean that they are killing all of the microorganisms which means that it is doing its job and sterilizing.
What type of surfaces can disinfectants be used on? Give an example of a disinfectant and a surface that it can safely be used on.
a. Hydrogen Peroxide- healthcare facilities (surgical tools and rooms)
What type of surfaces can antiseptics be used on? Give an example of an antiseptic and a surface that it can safely be used on.
a. Living tissue (cuts/broken skin) to keep microorganisms away
List two things that differentiate disinfectants and antiseptics
a. Antiseptics: chemical agents used to destroy or prevent the growth of microorganisms, applied on living tissues with zero injurious effect
b. Disinfectants: May not eliminate all bacteria, used in homes for cleaning bathrooms, kitchen and floors
What is a confluent lawn of bacterial growth and how is it different from isolated colony growth?
a. Confluent lawn of bacterial growth is a uniform layer of bacteria
b. Isolated colony growth is when you can see the individual colonies, confluent lawn is just bacteria all over
To obtain a confluent lawn of bacterial growth, which technique do you use—the streak-plate method or the spread-plate method? Explain.
a. Spread plate because you want there to be an even layer of bacteria. You want this because you want each disc to have the same amount of bacteria near it.
What happens to the antibiotic in the disc once the disc is placed on the agar?
a. It gradually goes into the agar killing bacteria
What is the zone of inhibition? Why does the size of the zone of inhibition matter?
a. Zone of inhibition is a measure of sensitive to a compound. The greater the sensitivity, the larger the zone is and vice versa. This matters because it can tell you have sensitive the bacteria is to the antibiotic.
What do you have to do to determine if your bacterial species is sensitive or resistant to a given antibiotic?
a. Measure the zone of inhibition, and compare it to a reference table.
