quiz questions 1-4 Flashcards
How should we view things in dark field?
Open the iris all the way
When using the 40X objective on the microscopes in the lab, what is the total magnification?
400
Instead of isolating Azotobacteria, aerobic nitrogen-fixing bacteria, Karen wants to isolate an anaerobic, nitrogen-fixing bacteria. How should she change the enrichment conditions?
Keep the bacteria in a closed container, the aerobic bacteria will use up all the oxygen then die, leaving the anaerobic bacteria.
Which molecule can be used as a terminal electron acceptor during anaerobic respiration?
nitrate
mannitol salts agar
Endospore formation is a type of reproduction.
False
A () cell undergoes sporulation to form an endospore, when conditions improve, the endospore can ()
- Vegetative, 2. germinate
No color change after adding doing the nitrate test, except when zinc is added.
Negative test result, micrococcus cannot break down the nitrate or do denitrification
What is the gram morphology for staph aureus?
Gram positive cocci
What characteristic of Pseudomonads are we using to enrich for them?
Pseudomonads can metabolize a very large range of substances, which is why we are using either acetate or arginine. They are also obligate aerobes, which is why they are being grown aerobically.
How do purple non sulfur bacteria function?
Can be chemoheterotrophs and phototrophs
colony morphology of azotobacteria?
slimy appearance
The presence of what key enzyme characterizes Pseudomonads?
cytochrome C oxidase
Main difference between industrial bread processing and starter culture
Sourdough starters contain a collection of wild yeast and bacteria present on the grains, while yeast used for industrial bread production is a monoculture of Saccharomyces cerevisiae.
What is/are the purpose(s) of salt in sauerkraut production?
To inhibit the growth of microorganisms, to draw sugar containing juices out of the cabbage for fermentation
Fungal rot on sauerkraut?
Leaving air pockets or bubbles in the cabbage solution, Allowing the top of the cabbage mixture to dry out
The endospore stain is primarily an example of which type of stain?
specialized
What trait(s) differentiate Acinetobacter species from Pseudomonas species?
they are nonmotile and oxidase negative
describe the difference between a bacteriostatic antibiotic and a bactericidal antibiotic.
Bacteriostatic: Halts growth but does not kill the cell
Bactericidal: Kills the cell
An environment with high levels of antibiotics will more likely exhibit higher numbers of antibiotic-resistant bacteria compared with an environment with low levels of antibiotics
true
w two shake tubes inoculated with an obligate anaerobe would be expected to differ in patterns of growth throughout the tube if one tube was incubated under aerobic conditions and the other was incubated under completely anaerobic conditions
Aerobic: Small zone with no growth at the top of the tube where oxygen is present in the media, growth throughout the rest of the tube.
Anaerobic: Growth throughout the tube
what are two reasons we use the small subunit ribosomal RNA gene to do phylogenetic studies?
-It exists in all living organisms
-It is large enough to contain statistically meaningful amounts of information
-It performs the same function in all organisms, so selection pressures on it should be the same in all taxa
-It contains highly conserved regions for comparing evolutionarily distant organisms and highly variable regions for comparing closely related organisms
-It is not transferred horizontally
In our attempt to isolate Bacillus, what does streaking the isolate on milk agar test for?
the ability to degrade casein
How do we successfully read the gelatin deep?
take out of incubation and refrigerate it
