Lab Final Flashcards
___________: proteins that function as biological catalysts for cellular chemical reactions
Enzymes
Biochemical tests use chemicals called ____________ that produce visible evidence of some form to indicate that a specific biochemical reaction has occurred
Reagents
What is the objective of the amylase test?
to determine if your unknown organism can catabolite amylose (starch)
Small monosaccharides that bacteria use as energy sources can easily pass through the cell membrane, often by way of specific ___________
Transporters
Small monosaccharides are catabolized inside the cell by __________________ ________________
Intracellular enzymes
Why do sugars need to be hydrolyzed into monosaccharides?
They are too bulky to be transported into the cell by specific transporters
What enzyme hyrdolyzes starch?
Amylase
Amylase and Maltase are _____-cellular enzymes that hydrolyze amylose into glucose
Extra
Starch turns into _______ with the help of _______ which then turns into _______ with the help of _________
Starch turns into maltose with the help of amylase, which then turns into glucose with the help of maltase
Bacteria that live in ______ are often capable of starch hydrolysis since starch is an abundant nutrient in soil
Starch
Starch reacts with _________ to produce a chemical complex that is dark blue or red brown
Iodine
What are the physical, positive results of the amylase test? What is the negative test result?
The positive amylase result will appear clear, and the negative amylase result will interact with the starch left in solution and appear dark in color
What is deanimation? What is the enzyme involved?
Deamination is an organisms ability to remove an amino acid from a molecule by using the enzymes deanimases
What is a decarboxylation? What is the enzyme involved?
The removal of the carboxyl group and the removal and modification of the R-side chains. The enzyme used is decarboxylase.
What is the goal of the cysteine desulfhydrase?
To determine if your unknown organism expresses cysteine desulfhydrase to catabolize cysteine
The first step in the biochemical pathway used to catabolize cysteine is the removal of _______________________
part of the R-group
What is the enzyme used to remove the R-group?
Cysteine desulfhydrase
What gas is released when the -SH is removed from the R group?
H2S (hydrogen sulfide gas)
Cysteine and water are converted by cysteine desulfhydrase into?
Alanine and Hydrogen Sulfide
How is cysteine digestion detected?
By the production of H2S
How is the production of H2S in cysteine digestion detected?
The interaction between iron ions and H2S will form a black substance
What color does the medium used in cysteine digestion starts out being, what color does it turn if cysteine digestion is occurring?
Yellow/cream to black
What is the objective of the lysine decarboxylase?
To determine if your unknown organism expresses lysine decarboxylase to catabolize lysine
The removal of a carboxyl group always results in the production of ______ gas and ________
CO2 and amine, cadverine
How do the products of lysine decarboxylase react with the bromcresol purple indicator?
Products make the solution more basic, which causes the indicator to be purple.
What are the variations of bromcresol purple under basic, neutral, and acidic conditions?
basic- purple
Neutral- brown
Acidic- yellow
What is the objective of urea digestion?
To determine if an organism expresses urease to catabolize urea
Ammonia is transported to the liver and converted into _______
Urea
Some bacteria can extract energy from ______ by converting it back into ammonia and CO2
Urea
What enzyme assists in the conversion of urea to ammonia?
Urease
What is the reagent of the Urease test? How does this test indicate a a positive or negative?
This urease test uses phenol red as the reagent. This test when positive for urea digestion turns red/pink
What is the color of the urea broth?
The urea broth has a pH of 6.8 which makes it straw-yellow.
What is the objective of the gelatin hydrolysis?
to determine if your unknown organism expresses gelatinase to digest gelatin
What is the extracellular enzyme that hydrolyses gelatin into peptides?
gelatinase
Why is it important to study whether a mo can hydrolysize gelatin at low temperatures?
Gelatin will naturally liquify at 37 degrees so it is important to avoid a false positive
What is the positive/negative of the amylase test?
(+)= clear zone
if the mo produced amylase and hydrolysized the starch there will be no starch to interact with the iodine
(-)= dark purple color
The mo does no hydrolyze the starch and therefore iodine will interact with the starch
What are the positive and negative tests of Cysteine Desulfhydrase?
Positive- black precipitate
Negative- no black precipitate
What is the postive and negative results for a lysine decarboxylase?
Positive: purple
Negative: brown/yellow
What are the positive and negative results of a Urea digestion test?
Positive- bright pink
Negative- no pink color
What are the results of gelatin hydrolysis?
Postive-liquid medium
Negative- solid medium
What differentiates staphylococci and streptococci?
The catalase tests. Strep are catalase negative. Staph are catalase positive.
How do we differentiate between staphylococci and micrococci?
Oxidase test.
Staphylococci are negative for this test and strep are positive for this test.
Staphylococcus epidermis are not pathogenic but can cause __________ ______________ under some circumstances
opportunistic infections
Staphylococcus aureus is a _____________ _______________ that causes diseases in even healthy individuals
Primary pathogen
A primary pathogen is largely due to the many ____________ ___________
Virulence factors
What are the four characteristics of S. Aureus that are useful for identification?
- Coagulase
- Fermentation of mannitol
- Heat-stable deoxyribonuclease (DNase)
- Beta hemolysis
S.aureus is also is most often an _________________ rather than an infection?
Intoxication
___________ is a selective medium, it contains 7.5% NaCl which inhibits the grow of halo tolerant organisms but allows growth of halophiles
MSA
MSA is selective for what?
Staphylococci
MSA is a differential medium. T or F?
T
What type of indicator is used within a test of fermentation fo mannitol? How does this indicate the positive or negative test?
Phenol red
This turns colonies that ferment the mannitol to yellow
DNase agar is differential. T or F?
T
DNase agar is not selective. T or F?
T
What materials are found within the DNase agar?
A rich source of nutrients, agar, methyl green as an indicator and large DNA molecules
What is the importance of the methyl green indicator within a DNase agar?
Methyl green
How does methyl green interact with DNase production?
Methyl green interacts with the large DNA molecules and forms a green complex
The absence of these DNA molecules becomes a colorless compound
A complete hydrolysis of red blood cells is called ______________
Beta-hemolysis
What is the partial lysis of RBC called?
Alpha hydrolysis
What is the complete lysis of RBC called?
Gamma hydrolysis
If the bacteria in question is susceptible to antibiotics there will be a _____________ ________________
Zone of inhibition
Microbial growth
An increase in the # of bacterial cells over time
Viral titer
The concentration of viral particles in a sample
The most widely used procedure for measuring the titer is the __________ ____________
Plaque assay
it uses grow inside a susceptible _______ cell
Host
The viral tiger is measured as the number of plaques that form on the lawn of host cells and it’s referred as the # of ______________ ____________ _______________
Plaque forming units
The number of PFU should be equal to the # ___________ _________
Of viral particles in the sample
___________ agar: is a bacterial growth medium with only 0.75% agar instead of the normal 1.5%
Top
How do you calculate the # of PFU/mL?
plaques x dilution factor/ mL of phage plated
How to calculate the total # of PFU units in the original sample
(PFU/mL)x the total volume in the original sample (mL)
Microorganisms that have adapted to living symbiotically on or in our bodies without causing disease are called __________
Commensals
Other terms for the collective group of symbiotic microorganisms that live on our bodies are ____________ flora and _____________ flora
Resident and indigenous
____________ is a relationship between two organisms of different species living together in a close and permanent association
Symbiosis
Who proposed Germ Theory of Disease?
Koch and Pasteur
______________: are microbes that are picked up from the environment temporarily and are not permanent residents of the microbial flora
Transient microbes
The ability of chemicals to damage pathogens without damaging human tissue is called ______________ ______________
Selective toxicity
______________: chemicals produced by a microorganism that inhibit the growth of or kill other mo
Antibiotics
Antibiotics that are effective only against either gram positive or gram negative organisms are called ____________ ______________ antibiotics
Narrow-spectrum
Antibiotics that are effective against both gram negative and gram positive are referred to as _____________ ____________ antibiotics
Broad-spectrum
Penicillin is a ______ spectrum antibiotic
Broad
The way that antibiotics affect the bacteria is known as _________ ___________
Mechanisms of action
Antibiotics that kill bacteria are called ________________
Bactericidal
Antibiotics that inhibit their growth are called _________________
Bacteriostatic
One of the most widely used tests to determine the sensitivity of a microbe to a specific antimicrobial agent is a ___________ ___________ test
Disk diffusion
What is a standardized form of a disk diffusion test?
Kirby-Bauer
If the microbe is affected by the antimicrobial it will not grow near the disk, producing a _____________________________
Zone of inhibition
The larger the zone of inhibition, the _______ sensitive the microbe is to that antibiotic
More
In a Kirby Bauer test what depth is required for the agar plate?
4mm
__________: are proteins produced by the B-lymphocytes of the immune system that have many functions in the protection against pathogens
Antibodies
Any molecules that is deemed as “foreign” and activates the immune system is called an _________
Antigen
The study of antigen-antibody interactions is called ____________
Serology
_________ is the clear liquid portion of the blood that remains after the blood is allowed to clot
Serum
___________ is the liquid portion of the blood including clotting proteins
Plasma
What is the difference between plasma and serum?
Plasma contains clotting proteins and serum does not
What is the similarity between plasma and serum?
Contain antibodies but lack blood cells
The concentration of antibody against a particular antigen is referred to as the ___________
Titer
The ______ test is a slide agglutination test used to diagnose salmonella infections
Widal
