+
Related Flashcards
Related Topics
Cards In This Set
| Front | Back |
|
What does the microbial world comprise of?
|
Bacteria, algae, fungi, protozoa and viruses.
|
|
What are bacteria that cause disease called?
|
Pathogens.
|
|
Which microbe was used as the first antibiotic?
|
Fungi
|
|
Why do we work near a bunsen burner when working with microbes?
|
It can be used to sterilized material and the hot air of the bunsen burner causes a current upwards which reduces the risk of contaminating the agar plates.
|
|
What is an inoculating loop and what is it used for?
|
It is a tool that is used to transfer microorganism and the loop is sterilized before and after transferring the microorganism.
|
|
Why are test tube cultures used?
|
A test tube that contains one of a variety of growth media. They can be fluid or solid. It is used for the maintenance of microorganisms as a source of material for microscopic and cultural study and in the study of physiological reactions of microorganisms.
|
|
Why are petri plate cultures used?
|
The oose fits of the plates allows for the exchange of gases between the inside and outside of the plates. They are used with different types of solid media and particularly useful to obtain isolated colonies of bacteria or to be able to count the number of bacteria in a culture. Most common solid medium is agar.
|
|
What is agar?
|
Agar is a gelling agent extracted from seaweed. Needs to be heated to 100 degrees but doesn't solidify until it is at 40 degrees. Nutrients can be added to accommodate growing needs of bacteria.
|
|
What method can we use to demonstrate viruses since we can't see them with a light microscope?
|
Look at the affect that viral bacteria called bacteriophage (phage) have on the host bacteria. Phage destroy the host cell by making them lyse to release virus proteins and DNA which makes it useful to observe viral activity.
|
|
When mixing T4 infected E coli with a suspension of E coli, what do the clear areas (plaques) on the agar plate represent?
|
The areas where the T4 have destroyed the bacteria cells. These plaques can be counted and from that you can calculated the density of infected phage e coli from the original suspension.
|
|
What was in the G bottle that was used in the E coli and T4 experiment?
|
It contained broth which was called the growth bottle.
|
|
How do mutants of bacteria occur when they all come from a single cell?
|
They arrise spontaneously as a result of errors in the replication of the DNA inherited by the daughter cells. Most mutations are disadvantageous and result in the death of cell but some will survive and exhibit a new characteristic.
|
|
How can we increase the rate of mutation of a bacteria colony above the normal one?
|
Exposing the culture to UV light. Many of the bacteria will be killed by the UV light but the remainders will mostly be mutated.
|
|
What type of bacteria did we use in the UV experiment?
|
Serratia marcescens
|
|
How do bacteria develop antibiotic immunity?
|
If a antibiotic is used but it doesn't destroy the entire colony, the remaining bacteria are resistant to the antibiotic and as the bacteria replicates, the whole bacterial community is now resistant to this antibiotic.
|
