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