Microbiology Lab 2 Flashcards

Terms Definitions
protozoans are classified by
how are viruses seen?
electron microscopy
What does disinfection destroy?
vegetative bacteria
Novobiocin Susceptibility Test
used to differentiate coagulase-negative staphylococci. usually to identifey novobiocin-resistant staphylococcus saprophyticus. Most other staphylococcus are susceptible to novobiocin.
Restriction enzymes recognize what sequences?
palindromic (AATGCATT)
Organisms, especially pathogens,can be cultivated at temperatures of _______ or slightly higher without fear of the medium liquefying.
37 degrees C
What is this cell arrangement? oooo
Along with maltase breaks down starch.
What does IKI stand for?
Grams Iodine
What are Distinct reddish-purple granules within cells that show up when the organisms are stained with methylene blue?
Metachromatic granules
Catalase Test
used to identify organisms that produce the enzyme catalase.Most often used to differentiate between catalase positive Micrococcaceaeand catalase negative Streptococcaceae.Catalase turns hydrogen peroxide into water and gaseous oxygen.When hydrogen peroxide is dropped on a species, if it begins to bubble (O2 formation) the test is positive for catalase
Trypsonoma Cruzi
causes Chagas' disease (from bug feces entering the eye. the disease is characterized by relaxing involuntary muscles such as the colon and esophagus.
After inoculation, petri dishes are incubated in an _________ position to prevent __________ that forms on the cover during solidification from dropping down onto the surface of the hardened agar.
inverted-- condensation
What color does the bacteria turn with the addition of iodine?
What is the round cell shape name?
Urease test
Many organisms convert urea to ammonia and water using urease. In this case the medium will become hot pink from an orangey-yellow color. (phenol red indicator will show when alkaline ammonia is produced).
What is casein?
A white protein in milk
What is an organism that is demonstrating several different shapes?
Lactose Non Fermenters
will produce colorless to slightly pink growth
the charged portion of a chomogen that allows it to act as a dye through ionic or covalent bonds between the chromogen and the cell
What technique other than fermentation was used to produce saukraut (Where microbes were used after one another to do different steps)?
Microbial succession. Lactobacillus and finally acid loving streptococci.
A culture containing a single unadulterated species of cells is called_______________.
a pure culture
What is the growth of bacterial cells on a solid medium that results from a single bacterium?
extracellular enzymes
Produced within the cell but work outside the cell often to breakdown large substrates into smaller transportable units (amylase, lipase, caseinase, gelatinase)
What does a durham tube look like?
Inverted tube
How do you interpret the catalase test?
Negative-no bubbling
An organism that uses citrate has a(n) (acidic/basic) pH?
What dye is used in the fluid thioglycollate medium?
What is teh most germicidal UV radiation?
260 nm
What is a medium that contains substances that causes some bacteria to take on an appearance that distinguishes them from other bacteria?
Differential medium
What is a Bacteria that prefers to grow in oxygen concentrations less than that found in the oxygen?
What are bacteria that can grow aerobically or anaerobically?
Facultative aerobes
Mannitol Salt Agar (MSA)
Used for isolation and differentation of pathogenic staphylococci, principally S. aureusContains carbohydrate mannitol, NaCl, and phenol redthe NaCl is used to be selective to staphylococci because they can live at high salinity.
Staph saprophyticus (recall causes UTI's) its test results are exactly the same as ___________________ except that it...
Staph epidermitis... except that unlike epidermitis it is resistant to novobiocin.S. aureus- sensativeS. epidermidis- sensativeS. saprophyticus- resistant
What is Epidemiology?
the study of the causes, occurence, transmission, distribution, and prevention of diseases in a population
Give 6 types of sterilizing heat.
1.direct flame2.hot-air oven3.boil water4.autoclave5.fractional sterilization7.hot oil
What is a chemical used on the skin to inhibit growth of microorganisms?
What part of the name of bacteria should be capitalized?
the genus
Litmus milk as a pH indicator
lactose fermentation yields acid:Pink- lactose fermentedPink on top only and curd- excessive fermentationDeep blue- breakdown of milk proteins (casein)Brown and purple/blue at top-proteolysis of milk protein
What kind of medium is used for nitrate reductase test?
Nitrate broth
What test uses the litmus milk tube?
Litmus milk test
What are antiseptics?
Substances such as alcohol or betadine that inhibit microbial growth or kill microorganisms
What is an example of a facultative aerobe?
E. Coli
What is an example of a basic dye?
Methylene blue
What type of bacteria is clostridium sporogenesis? What shape? Aerobe or anaerobe? Spore former?
Gram positive
Rods (Bacilli)
Staph aureus causes what in humans
A list of things including:septicimia, endocarditis, acne, food poisoning
What do Alpha Hemolysins do?
Partial destruction of RBCs and produces a greenish discoloration of the AGAR around the colonies
What does oil immersion do?
improves resolution and does not increase the magnificaton
Bacteria that thrive in room temperature
Mesophiles (E. coli, S. Marcescens)
What is used to test for the presence of enzyme catalase?
Catalase Test
What are facultative aerobes?
Bacteria that can grow aerobically or anaerobically
Before bacterial cells are to undergo transformation (uptake of naked DNA) they must first be made ____________. 2 exceptions
Competent; Bacillus subtilus and Streptococci pneumonia
Biohzardous labels:B-R-Y-W what do these letters stand for?
Blue - health hazard (inhale, skin, eyes, ingest)Red - Flammable (organic solvents: alcohol, ether)Yellow - Reactive-very explosive or corrode. (acids, alkali, corrosive materials)White - Protective equipment - need goggles, shoe covers, etc..
How does fractional sterilization kill endospores?
Puts them in a vulnerable vegetative state
Litmus milk test serves two purposes:
1.) redox indicator- showing whether the medium was reduced or oxidized by changing color.2.) pH indicator- showing if the medium is acidic or basic following the activities.
What is a fluid thioglycollate medium composed of?
Glucose, Cystine, and Sodium Thioglucollate to lower the oxidation reduction potential
What is the first step when you enter the lab?
Disinfect with decon
What is the effect of temperature on S. aureus?
S. aureus are mesophiles
What were the two bacteria used in the motility lab? Were they motile?
M. luteus-non-motile
P. vulgaris-motile
in gel electrophoresis why is water not used?
Because deionized water would not produce current and the DNA fragments would not move. Instead a buffer is used.
What is the problem in treating patients against protozoans?
They are eukaryotes so standard antibiotics do not work. infact any pharmaceuticals that damage the parasitic cells may also damage eukaryotic host cells as well.
1st step in culture transfer techniques for an 'aseptic transfer' of microorganisms.
An inoculating needle or loop must always be sterilized by holding it in the hottest portion of the Bunsen burner flame, the inner blue cone, into the entire wire becomes red hot.
What happens if microbiologists allow for the bacteria in a slant to consume all of the nutrients/.
They risk losing that particular line of bacteria.
Why are buffers NOT necessary in nutrient broths?
because they contain natural buffers in the form of zwitterions from amino acids which can donate or accept protons (brownsted-lowry definition of acid/base).
How do you interpret the Citrate utilization test?
Positive-abasic PH causes media to change from green to prussian blue
Negative-no color change
What are the organisms used for the antibiotic experiment?
S. aureus
E. Coli
P. vulgaris
P. aeruginosa
EMB agar under acidic conditions
form into dark purple, a long with a green metallic sheen possibly
how did we test the antibiotic effect on bacterial growth?
Kirby-Bauer paper disc technique. On Mueller-Hinton platea lawn of bacteria is grown and papers with antibiotics diffuse into the plate causing zones of inhibition which determine its effectiveness against the bacteria.
Besides grouping into one of three classes, the bactercult test also had another test. what was it? results?
A colony count.< 25- no UTI25-50= suspicion of UTI> 50 = indicates infection
How is point Prevalence calculated?
Number of existing cases at a point in time over the total population X K
How can we disinguish between Micrococcus luteus and bacillus cereus?
Both are gram positive and have a cocci morphology BUTMicrococcus luteus are often found in tetrads or pairs.
What is the procedure for oxygen requirement test?
Boil and cool FTM
Inoculate media the organism with loop. Do not shake media
Incubate at optimum temp for 24 hours
Look up stains online to see pictures
Look up stains online to see pictures
in electrophoresis how does one see the movement and what does the movement quantify?
Tracking dye is added to measure the displacement. it quantifies conformation, size and charge of the samples.
What is the purpose of a slant surface area in an agar slant?
Slant will increase the surface area to work with.
What is the purpose of the broth inoculating method?
So that large quantities of bacteria can be grown in a short time.
What is the citrate utilization test used for?
To determine if an organism is capable of using citrate as the sole source of carbon with production of enzyme citratase
What is a major problem now a days with using antibiotics? solution?
Alot of strains are resistant to them.Synergism- using a combination of antibiotics seems to be effective.
What is the procedure for discovering if an organism is motile?
Use a needle to inoculate by making a single stab about two thirds down and then pull out the needle along the same path
Incubate at optimum temperature for 24-48 hours
What results did we expect in the gel electrophoresis lab where we cut DNA singly or doubly with restriction endonucleases?
We would expect those that were cut twice (much smaller pieces) to have two different final stains in the same sequence and to have moved further than any of the singly cut fragments.
What is the purpose of the agar streak method?
The mass of the media is diluted out through the four quads.
How do find out how many colonies are in an original sample?
1. Count all plates, and get rid of any less than 30 or more than 300.2.Make the negative exponent positive3.Then, make the exponents the same number.4.Average the numbers.5.Use the unit col/ml.
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