Quiz 1-6 Flashcards
Flat, convex, or raised
descriptions of the colony elevation
uniforms fine turbidity
a motile bacterium might exhibit this in a liquid culture
Pellicle growth
bacterial type forming a thick floating mass of cells on the surface of a liquid culture
sediment
mass of bacterial cells settling at the bottom of the liquid culture
The fact that microorganisms are ubiquitous means that they …
are all disease-causing
are found almost everywhere on Earth
exist in pure culture in nature
are found only in certain specialized habitats on Earth
all the above
are found almost everywhere on Earth
The results of lab exercise 2-1 shown below are, among others, the reason why
aseptic technique methods were developed.
you would disinfect the microbiology lab
countertop prior to working in that space.
handwashing is important.
all the above
all of the above
When growing bacteria, the choice of solid media (agar slant or agar plate) or liquid media depends on what you wish to accomplish; each of the three types is best suited for a particular purpose. Evaluate the following and choose the one that is incorrect; i.e., the medium type does not match its correct function.
best for pure culture determination: solid-agar slant medium
best for obtaining/harvesting lots of cells: liquid medium
best for obtaining isolated colonies: solid-agar plate medium
best for growth studies or DNA/protein isolation: liquid medium
best for pure culture determination: solid-agar slant medium
A mixed culture does not necessarily indicate a contaminated culture.
true or false
true
Colony size, color, and shape are important factors used to describe bacterial growth. What other physical factor should be included in the description since it can influence the growth characteristics?
Incubation temperature
Duration of incubation
Type of growth medium used
All the above should be included as part of the description of bacterial growth.
All the above should be included as part of the description of bacterial growth.
An environmental (soil) sample obtained from a temperate region was transferred to a liquid growth medium and incubated at 30°C for 24 hours, then transferred to solid growth medium in order to isolate bacteria from the original sample. Following 48-hour incubation at 30°C, the picture of the solid medium shows the results of this experiment. Which of the following statement(s) among A - C are true regarding this experiment?
This plate represents a pure culture.
Isolates A and B are likely the only bacterial types that would have been present in the original environmental sample.
Isolate A and Isolate B are probably the same microorganism
two of A - C are correct
NONE of A - C are correct
NONE of A - C are correct
It has a numerical aperture value that contributes to the resolution
condenser lens
100 x objective lens
use with immersion oil
scanning objective lens
typically has the lowest magnification power
controls the amount of light entering the lens system of a microscope
iris diaphragm
Which statement is true regarding prokaryotic cells, eukaryotic cells, and viruses?
There are two major taxonomic groupings (domains) of prokaryotes.
You would expect the size of Coronavirus to be in the 1 to 10 micrometer range.
Prokaryote cells are generally more complex and larger than eukaryotic cells.
Within the domain Eukarya, yeasts, algae, protozoans, and archaea are representative types of microorganisms.
Two of the above are true.
There are two major taxonomic groupings (domains) of prokaryotes.
Which is a false statement among A - C regarding the oil immersion technique?
it is generally required for viewing prokaryotic cells in order to make the most accurate observations of cell morphology and arrangement.
immersion oil is placed directly on top of the specimen to be viewed
if paired with a 10X ocular lens, it would allow for a maximum total magnification of around 100X
A, B, C are all true statements
if paired with a 10X ocular lens, it would allow for a maximum total magnification of around 100X
The limit of resolution of the 40X objective lens of your microscope is determined to be 360 nanometers. Will you be able to distinguish two points that are 365 nanometers apart or will they blur into one?
They will blur into a single point.
One cannot determine this from the information given.
They will be seen as two separate points very close together.
none of the above
They will be seen as two separate points very close together.
Most microscopes are parfocal. This means that the distance from the nosepiece opening to the focal plane of each lens has been standardized. What does this mean to you with regard to how you use the microscope?
When the specimen is in focus, the slide will always be the same distance away from the end of the lens no matter which lens is being used.
Once the specimen is in focus under a low-power lens, the microscope can be switched to a higher-power lens without moving the stage and the image will be in or nearly in focus no matter what lens is used.
All lenses will need to be used the same way, either through air or through oil.
It means you never need to adjust the amount of light coming in.
Once the specimen is in focus under a low-power lens, the microscope can be switched to a higher-power lens without moving the stage and the image will be in or nearly in focus no matter what lens is used.
The smallest cell size would likely be seen among certain members of which group?
viruses
Which of the following procedures in A-E is incorrect in properly executing aseptic technique or otherwise minimizing chances for contamination?
flame wire loop until it glows red
hold the tube cap in your hand, don’t place it on the countertop
hold open tubes at an angle
flame culture tubes before and after transfer of culture
incubate plates lid side down
A-E are all the correct procedures to do
A-E are all the correct procedures to do
Which of the following choices describes a negative stain?
Use an acidic stain and basic stain combination to produce dark-stained cells in a light-stained background
Use an acidic stain to yield un-stained cells in a dark-stained background
Use an acidic stain and basic stain combination to reveal light-stained cells in a dark-stained background
Use a basic stain to give un-stained cells in a dark-stained background
Use an acidic stain to yield un-stained cells in a dark-stained background
Which of the following is not part of the proper protocol for performing a simple stain?
If a plate culture is your source of bacteria, make sure to mix the bacterial sample in a drop of water
Make sure to air dry the smear before passing through a flame
Use an aseptic technique when transferring bacteria to the slide
Make sure you have a large sample of cells to prepare a very dense, thick smear
Cover the smear with a basic stain for a minute, rinse, then blot dry
All the above are proper steps to perform a simple stain
Make sure you have a large sample of cells to prepare a very dense, thick smear
Basic growth media must be formulated to meet the diverse nutritional requirements of routinely cultivated bacteria, which includes supplying sources of ____________ and nitrogen in various forms. If these nutrients are supplied in the form of animal extracts like peptone or beef extract, the growth medium is termed a _______________ medium.
oxygen; defined
agar; complex
carbon; defined
yeast extract; defined
water; complex
carbon; complex
carbon; complex
If a particular bacterial species has a cellular morphology described as “pleomorphic”, then
it must be of uniform shape and size.
it is considered a streptobacilli.
it probably consists of irregular forms, branching forms, and non-uniform cells.
it is a spirochete.
it is a combination of tetrads and cocci
it probably consists of irregular forms, branching forms, and non-uniform cells.
