microbiolab midterm
Prokaryotic cells are typically __________ while eukaryotic cells are _________ . Prokaryotic cells have DNA and lack _______
0.1-10 10-100 circular membrane-encloser nucleus
1. Hold the lid of the plate over the agar to prevent contamination 2. Take a sample from your original culture after the very first step. 3. Put your lid upside down on the bench 4. Stay close to the flame while working/keep area sterile 5. Take a big chunk of culture, barely touch one isolated colony 6. Use sterile culture loop
1. do 2. dont 3.
put procedures in order
1. label agar plates 2. flame inoculating loop over a flame/use a new inoculating loop from package 3. touch top of an isolated colony to transfer 4. streak the plate 5. incubate plate
indirect cell count includes: ___________________________, which is the measurement of how dense a liquid is using a laser to refract light through the liquid, and giving a measurement. ___________________________, which is the measurement of a substance at the end of a chemical reaction such as acid like vinegar or other by products.
1. optical density measurement 2. end product determination/kinetic reaction
if you counted 120 colonies on your 10-4 petrifilm when you used 100 µL of solution, what is the bacteria count for this film?
1.2*107 CFU/mL
You have plated 100 ul of 10-fold dilutions 10^-5, 10^-6, and 10^-7 from an initial saliva sample. You count 350 colonies on the 10^-5 plate, 160 colonies on your 10^-6 plate, and 15 colonies on your 10^-7 plate. What is the CFU in the original sample in scientific notation? *the volume of the serial dilutions is 10ml
1.60 x 109
Select all of the following that are a 1/10 dilution (the red boxes are the amounts in question, only pay attention to the numbers in the red boxes for this question)
1/9 2/18 200/1800
With what objective can you use immersion oil?
100x
Find the average CFU/mL for the following (Do not use scientific notation): 10^-1 --------- 3246 colonies 10^-2 --------- 1434 colonies 10^-3 --------- 320 colonies 10^-4 --------- 237 colonies 10^-5 --------- 87 colonies 10^-6 --------- 42 colonies 10^-7 --------- 22 colonies 10^-8 --------- 2 colonies
17690000
Master Mix Contains
2.5 uL 1492R Primer 2.5 uL 8F Primer 12.5 uL of Taq Hot Start Mix 2.5 uL Sterile PCR Water
How many domains did Carl Woese propose organisms be classified into, and what were their names?
3: Bacteria, Archaea, Eukarya
How many bacteria, in CFU/mL, were in your original sample? Submit your answer in scientific notation and round to the nearest tenth.
750000
____________ is a measure of number of viable organisms. Each life organisms that is put onto the plate will form on clonal colony.
CFU
If you were to gram stain a fungi/yeast culture, you would be able to see the morphology of the fungi/yeast
FALSE
Immersion oil can be used on the 40X and the 100X lenses.
False
Immersion oil can only be used in the 40x and 100x objective lenses. However, it cannot be used on the 4x and 10x lenses because it can damage them.
False
which is the smallest fragment produced by a restriction enzyme which is the largest?
G and C
Which of the following is NOT part of aseptic technique?
Leaving your pipette tip box open
Which media is both selective AND differential?
MacConkey Agar and Mannitol Salt Agar
Which of the following is true? Standard deviation:
Measures the spread of the data about the mean value Is useful when comparing sets of data with the same mean but a different range
Obligate aerobe aerotolerant faculative obligate anaerobe
Obligate aerobe: no growth in anaerobic chamber aerotolerant: growth in anaerobic chamber, better than with oxygen Facultative: grows well in anaerobic chamber and grows well in oxygen Obligate anaerobe: growth in anaerobic chamber but no growth on oxygen exposed plates
Streaking for isolation is useful for PCR Gram Staining Eating Diagnostic Techniques Subculturing
PCR, gram straining, diagnostic techniques, subculturing
If your petrifilm has 560 colonies on it, what would you report in your results?
TNTC
Most bacterial antibiotics will not kill fungi and yeast
TRUE
In what type of media did you culture microbes from the environment?
TSA
Which of the following is not proper aseptic technique?
Wearing lab coats in and out of the lab
Microbial growth can be affected by _________. Select all that apply. nutrients availability temperature Temperature will increase enzyme activity, but if temperatures get too high, enzyme activity will stop and the enzymes will denature. oxygen availability Depending on the bacteria being grown, oxygen availability varies; but this is important to know salinity
all
Over-sterilization or prolonged heating will change the composite of the media including: A decrease in the gelling properties of agar Caramelization or darkening of the medium The development of a nontypical precipitate Incorrect pH Loss of selective or differential properties Loss of nutritive value All of the above
all of the above
Phylogeny is: a) none b) The evolution of a genetically related group of organisms as distinguished from the development of the individual organism c)Used to reflect the hierarchical classification of taxonomic groups nested within more inclusive groups d) all of the above
all of the above
BLAST STANDS FOR
basic local alignment search tool
Certain work practices, safety equipment, and specialized facilities designed to minimize exposure to infectious agents are defined as
biosafety
when setting up the agarose gel fro electrophoresis the wells must be placed at which end of the gel box
cathode
Which organism is photosynthetic?
cyanobacteria
Denaturing occurs at: Annealing occurs at: Extension occurs at
denaturing --> 95 annealing --> 45 extension --> 72
DNase agar
differential
blood agar
differential
in the gram staining procedure, what is the decolorizer?
ethanol
Bacterial Growth occurs through binary fission, which leads to overall _____ growth.
exponential
100x TAE buffer solution composed of Tris base, acetic acid and EDTA, used to make agarose gels for gel electrophoresis and used to run gels
false
Gram-negative appear purple under the microscope due to the thicker layer of peptidoglycan.
false
Gram-negative bacteria have a a thicker peptidoglycan layer.
false
When growing a microorganism contamination must occur
false
a dilution is an increase of concentration by adding diluent in a certain ration
false
all eukaryotic organisms are multicellular
false
it is okay to throw away culture tubes with metal caps.
false
there is only one way to streak
false
Which type of hemolysis is pictured here?
gamma
The time interval required for the cells (or population) to divide is called the
generation time
which of the following is not a variable for incubation listed in the lab manual?
incubator model
What are some limitations to the flow cytometer?
labor intesnive, the sample has to be processed it is expensive it does not differentiate between living and dead cells
Due to how bacteria grow, bacterial growth curves are
logarithmic and exponential
DNA is __________ charged, therefore when conducting gel electrophoresis you must run the gel from the ____________ electrode to the ______________ electrode
negatively negative positive
Not allowing your loop to cool off before picking up a colony sample will result in
no growth
tryptic soy agar
non-selective media
whats the main tool used for aseptic transfer of cultures, suspension of natural materials and sterile solutions and adequate control of volume to be transferred?
pipettes
Any identification and biochemical tests can only be performed on a ______ culture.
pure
what color is B. Subtillis after a gram stain
purple
_______________ media allows certain organisms to grow and inhibits the growth of other organisms.
selective
MacConkey agar is selective for _____________________ and differential for ____________________
selective --> gram negative bacteria differential --> lactose fermentation
MacConkey agar
selective and differential
mannitol salt agar
selective and differential
amoeba
single celled animal that catches food and moves by extending fingerlike projections of protoplasm
Diatom
single-celled algae that as a cell wall of silica
Protozoa
single-celled, non-photosynthetic protist, such as ciliates, amoebae, and flagellates
where do you throw away pipette tips, contaminated cotton swabs, & transfer pipettes?
small autoclave bag biohazard bag
________________ process is a treatment process from which the probability of microorganism survival is less than ___________
sterilization 10-6
An example of an extremophile
tardigrade
What is the scientific name of this organism
tardigrade
On a gel, which fragment has the lowest molecular weight?
the fragment that has traveled the furthest
A student is practicing pipetting and seems to have a problem. When she is in lab, she always pipettes the same volume, however it is not the intended volume. Which statement below is true?
the student is precise, but inaccurate. this is most likely due to systematic error
What hand digit do you use to press on the pipette plunger?
thumb
Different colonies have different colony sizes and morphologies
true
E. coli is rod shaped
true
Protozoa/ Protozoans is a term used to designate single-celled, non-photosynthetic protists such as ciliates, amoebae, and flagellates.
true
Subculturing is important to maintain cultures or to prepare fresh cultures for various examinations
true
TNTC - Too numerous to count is when the number of colonies on a plate is greater than 300
true
When making agar it is recommended to use purified deionized water
true
pure colonies are usually clonal
true