2 pt 3 pt 4 pt 5pt 1 pt 2 pt 3 pt 4 pt 5 pt 1 pt 2pt 3 pt 4pt 5 pt 1pt 2pt 3 pt 4 pt 5 pt 1 pt 2 pt 3 pt 4pt 5 pt 1pt Bacterial Counts Oxygen and Temperature Salt and heat UV and antibiotics Staph project
When you count colonies on a plate, is it direct, indirect, total or viable?
Direct and viable
When you count colonies using a spectrophotometer, is it direct, indirect, total or viable?
Indirect and total
As transmittance increases, turbidity increases or decreases?
Decreases
If you take 1ml of a culture and add it to 9 ml of media, what kind of dilution is this?
1:10
If you had 3 plates in front of you and 1 plate had 500 colonies, one had 120 colonies and one had 3 colonies, which one would you use to determine the concentration of bacteria in your original culture?
The one with 120 colonies
If your organism grew throughout a thioglycollate tube but benefited from oxygen, how would you classify it?
Facultative anaerobe
If an organism grows at low oxygen, what is it called?
Microaerophile
How would you classify an organism that grows optimally at 37 degrees C?
Mesophile
What is the optimal growth for Serratia marcescens and how would you classify this organism?
25 degrees C, psychrotroph
What color are the colonies of Serratia marcessans at 25 degrees C?
Red or pink
An extreme or obligate halophile grows at what salt concentration?
15%
Organisms that can grow at salt concentrations up to 10% are called ____________.
Facultative halophiles
Why are Bacillus most resistant to heat than other organisms?
They have endospores
What is to the time to kill all cells in a culture at a given temperature?
Thermal death time
What is the time, in minutes, to kill 90% of a population at a given temperature?
Decimal reduction time
What does UV irradiation do to the DNA?
It creates thymine dimers
Is UV radiation ionizing or nonionizing?
Nonionizing
For the UV experiment, the side of the plate covered with the index card, had more or less colonies?
More
When you place an antibiotic disc on a bacterial plate, do you measure the radius or diameter of the zone of inhibition the next day?
Diameter
What are some reasons for antibiotic resistance?
Using antibiotics too often or when not needed Plasmids with antibiotic resistance genes Bacteria can pump out antibiotics
Is the m-Staph broth, selective, differential or both?
Selective
Are the MSA plates selective, differential or both?
Both
SHOULD Novobiocin be sensitive towards Staphlocococcus aureus, Staphylococcus epidermidis or both?
Both
How does Staphyloslide work?
The antibodies in Staphyloslide bind to the antigens on Staph. aureus
Which organism(s) tests positive for coagulase?
Staphylococcus aureus