Flashcards Microbiology UTA 2460 - Lab Practical 2 | Quizlet

What is the role of resazurin in fluid thioglycolate medium...

Resazurin indicates the presence of oxygen in the media

A bacterial isolate is subcultured to two blood agar plates, one of which is incubated in an anaerobe jar, and the other is incubated on a shelf in the incubator. After incubation, growth is observed on the plate from the anaerobe jar, but there is not growth on the plate incubated on the incubator shelf. Based on these results how would this organism be categorized...

obligate anaerobe

Where would you predict an facultative anaerobe would grow in a tube of fluid thioglycolate medium...

throughout the tube

The pink color in the top of the broth in an FTM tube indicates...

the presence of oxygen

Both human pathogens and normal microbiota are typically classified as...

mesophiles

Taq polymersae is a DNA polymerase enzyme that demonstrates maximal activity at 72C. The organism from which this enzyme was isolated would most likely be classified as a...

thermophile

Vibrio cholerae is the bacterium responsible for cholera, a GI tract infection. Normally, it takes the ingestion of over one million bacterial cells to cause infection, but the consumption of antacids significantly lowers this number. What does this tell you about the likely classification of V. cholerae in terms of pH preference...

it is likely an alkaliphile

How does pH negatively affect the metabolism of microorganisms...

pH changes can denature enzymes

Why can jams and honey be stored at room temperature for long periods of time...

the high sugar content causes plasmolysis of bacterial cells

Microorganisms that can grow at salt concentrations as high as 15-30% are known as...

halophiles

An experiment involves the inoculation bacteria onto a variety of media with NaCl concentrations ranging from 1% to 25%. Which of these media is most likely to be isotonic with the bacterial cells...

1%

Which of the following would be appropriately sterilized using UV radiation...

stainless steel surface in biological safety cabinet used for media preparation

Which of the following infectious agents is least likely to be damaged by UV exposure...

prions

When two adjacent thymine molecules are joined by a covalent bond as a result of exposure to UV light, this structure is referred to as a...

thymine dimer

How are agar plats inoculated for disk diffusion testing of antiseptics and disinfectants...

a swab is used to inoculate the entire surface of the plate, producing a lawn of growth

How is an antiseptic different from a disinfectant...

an antiseptic is used to remove to kill microorganisms on tissue, whereas a disinfectant is used to remove or kill microorganisms on inanimate objects

Please choose the method of antimicrobial susceptibility testing that involves measuring and evaluating zones of inhibition around antibiotic disks placed on a culture of bacteria prior to incubation...

Kirby-Bauer test

A large zone of inhibition around a disk containing disinfectant generally indicates that the bacteria being tested is resistant to the disinfectant...

false

Which choice below briefly describes the Kirby-Bauer method of antimicrobic sensitivity testing...

disk diffusion

A chemical compound, regardless of its source (either natural or synthetic) that is capable of killing or inhibiting microorganisms is referred to as...

an antimicrobial

A phenol red glucose broth with a Durham tube has been inoculated and incubated. After 48 hours, the broth is turbid and bright yellow and approximately half of the contest of the Durham tube have been displaced with gas. Interpret these results...

the organism is fermenting glucose

Bacterial fermentation of sugars usually results in __ end products whereas breakdown of proteins and amino acids results in the formation of __ end products...

acidic, alkaline

You have set up a series of biochemical tests on a gram negative bacilli and have obtained the following results: Using the flow chart provided, determine the identification...

Oxidase - motility + Citrate + H2S - Methyl red - urease - Lactose ferm + indole - Glucose ferm + nitrate reduction +

Enterobacter aerogenes

If an organism growing on Kligler's iron agar ferments glucose, but NOT lactose, why does the slant ultimately turn red...

when the glucose supply is exhausted, the organism turns to peptone degradation, releasing alkaline end products

Tryptophan hydrolysis results in...

the production of indole

The identification schema within Bergey's Manual of Determinative Bacteriology are based on...

morphological and physiological characteristics

An organism that ferments glucose via the mixed acid fermentation pathway will be...

red in the methyl red test

How would a result be reported if the organism does not grow on citrate agar and the color stays green...

citrate negative

The cytochrome oxidase enzyme detected by the oxidase test functions within the cell as part of...

the electron transport chain

Hydrolysis of urea results in...

alkaline end products

What indicates a positive catalase test...

bubbles

During aerobic cellular respiration, H2O2 is produced as a waste product that is classified as a...

reactive oxygen species (ROS)

What color do disease causing staphylococci produce on the mannitol salt agar plate...

colonies grow and turn the plate yellow

__ cause partial lysis of red blood cells, __ cause complete lysis of red blood cells and __ do not lyse red blood cells...

alpha-hemolysins, beta-hemolysins, gamma-hemolysins

What is the result of this coagulase test...

negative

What type of sample is the novobiocin sensitivity test usually performed on...

urine isolates that are coagulase negative

Bacitracin would not be effective in which scenario...

A & B (Bacteria with no cell walls, Bacteria that are not growing)

What is the CAMP test used for...

Streptococcus agalactiae

What organism does the optochin sensitivity test identify...

Streptococcus pneumoniae

What organism does the bile-esculin test differentiate between...

group D streptococci from non-group D streptococci