Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
80 Cards in this Set
- Front
- Back
What is the reagent that serves as the substrate in the catalase test?
|
H2O2; hydrogen peroxide
|
|
What type of metabolism is associated with catalase production?
|
aerobic metabolism
|
|
For what product is one testing when using the catalase test?
|
oxygen in the form of bubbles
|
|
If your catalase test was POSITIVE, to what 2 possible genera could the microorganism belong?
|
Staphylococcus and Micrococcus
|
|
What genera of bacteria is the catalase test used to distinguish between?
|
Gram-positive cocci
catalase POSITIVE: Staphylo and Micro catalse negative: Strepto, Lacto, and Entero |
|
Equation catalyzed by catalase
|
2 H2O2 -> 2H2O + O2
|
|
Enzymes that are essential to the cell and are produced at all times
|
Constitutive enzymes
|
|
Enzymes produced only if the appropriate substrate is available
|
Inducible or adaptive enzymes
|
|
Enzymes that act outside of the cell in which they are produced
|
Exoenzymes
|
|
Enzymes that act inside the cell
|
Endoenzymes
|
|
Enzymes
|
proteins that serve as biological catalysts and are NOT consumed in the reaction
|
|
What is the function of cytochrome oxidase?
|
The enzyme catalyzes the oxidation of cytochrome and reduction of O2.
Required to generate the H+ gradient used to produce ATP through the ETC |
|
Oxidase test used to differentiate among which groups of bacteria?
|
Pseudomonads (positive) - Pseudomonas putida
Enterobacteria (negative) - Escherichia coli |
|
Amylase breaks down _____.
|
Starch; alpha-1,4- glycosidic bonds between glucose molecules
|
|
Cellulase breaks down _____.
|
Cellulose; beta-1,4- glycosidic bonds between glucose molecules
|
|
Which organism studied was amylase positive? amylase negative?
|
POSITIVE: Bacillus subtilis
negative: Escherichia coli |
|
Which organism studied was cellulase positive?
|
Cytophaga hutchinsonii
|
|
Proteases
|
enzymes that hydrolyze proteins into peptides so they can be transported into the cell
|
|
Peptide
|
short chain of amino acids
|
|
Protein
|
amino acids joined by peptide bonds
|
|
Which organism studied produces caseinase?
How do you know? |
Bacillus subtilis
clear under colony on milk agar plate |
|
Which organism studied produces gelatinase?
How do you know? |
Bacillus subtilis
clear under colony on gelatin agar plate after flooded with HCl |
|
Catabolism can utilize which two (2) pathways?
|
(1) Respiration (if terminal e- present)
(2) Fermentation * Glycolysis common to both |
|
Possible Fermentation Products
|
(1) CO2
(2) acids (3) alcohol |
|
What indicator is used in determining carbohydrate fermentation?
|
Phenol red
(yellow under acidic conditions) |
|
Fermentation Products detected with Saccharomyces cerevisiae
|
CO2 and ethyl alcohol
|
|
Fermentation Products detected with Lactococcus lactis
|
lactic acid
* causes casein protein in milk to coagulate |
|
Carbohydrate Broth Results for
Citrobacter freundii |
G, L, S (AG)
|
|
Carbohydrate Broth Results for
Staphylococcus epidermidis |
G, L, S (A)
|
|
Carbohydrate Broth Results for
Escherichia coli |
G, L (AG)
|
|
Carbohydrate Broth Results for
Bacillus cereus |
G (A)
|
|
Cysteine desulfhydrase
|
cleaves sulfydryl group (‐SH) from cysteine releasing hydrogen sulfide gas (H2S)
2 of 20 amino acids contain sulfur ‐Cysteine & Methionine |
|
Which organism studied produces cysteine desulfhydrase?
|
Citrobacter freundii
|
|
Peptone Iron Agar
|
used to test for cysteine desulfhydrase
peptone is rich in cysteine ferric citrate + H2S = FeS (ferrous sulfide) |
|
IMViC series
|
tests to distinguish coliforms (E. coli and E. aerogenes)
Indole Methyl Red Voges-Proskauer Citrate |
|
Indole Test
|
part of IMViC for coliforms (E. coli POSITIVE)
tryptonphan (tryptophanase) -> indole, pyruvic acid, ammonia + Kovac's reagent = RED top layer |
|
Methyl Red Test
|
part of IMViC for coliforms (E. coli POSITIVE)
Mixed acid fermentation = RED |
|
Voges-Proskauer Test
|
part of IMViC for coliforms (E. aerogenes POSITIVE)
Butanediol fermentation (acetoin) = pink/orange/red |
|
Simmons Citrate Test
|
part of IMViC for coliforms (E. aerogenes POSITIVE)
> Sodium citrate is only C source > Ammonium phosphate as only N source > Bromthymol blue is pH indicator Citrate permease = produce alkaline products = BLUE |
|
Bromthymol blue
|
pH indicator in Simmons Citrate Test of IMViC
|
|
Denitrification
|
reactions that reduce nitrate to nitrogen gas
In anaerobic respiration some use nitrate as external electron acceptor > Paracoccus denitrificans |
|
What is the organism studied that produces nitrate reductase AND nitrite reductase?
|
Paracoccus denitrificans
|
|
What is the organisms studied that produces nitrate reductase?
|
Escherichia coli
|
|
Nitrogen fixation
|
ability of an organism to obtain N2 from the air and convert it to ammonia and organic nitrogen
Symbiotic relationship with plants OR free‐living (non‐symbiotic) |
|
Enzyme Complex used by organisms that fix nitrogen
Enzyme inhibited by oxygen |
nitrogenase enzyme complex
Dinitrogenase reductase |
|
Which organism studied is free-living and nitrogen-fixing?
What qualities does it have to accomplish this? |
Azotobacter vinelandii
> Protein bound to the nitrogenase complex to protect the dinitrogenase reductase from O2 > Alginate capsule that slows the rate of oxygen absorption |
|
Hemolysin
|
a substance produced by a bacteria that damages/destroys red blood cells; virulence factor
|
|
Alpha Hemolysis
|
leakage of ions from red blood cells caused by alpha‐hemolysin proteins
Ex. Streptococcus mutans |
|
Beta Hemolysis
|
complete rupture of red blood cells caused by beta‐hemolysin proteins
Ex. Streptococcus pyogenes |
|
Gamma Hemolysis
|
no effect on red blood cells; no hemolysins
|
|
Method of Isolation and Identification of Streptococci
|
Blood agar to determine hemolysin production
Used candle jar because Streptococci found in human body prefer increased CO2 (microaerophilic) |
|
Virulence Factor
|
structures or substances produced by a microorganism which enhances its ability to cause disease
Ex. capsules, coagulase, hemolysin, endospores |
|
Aerotolerant anaerobes
|
can grow in presence of oxygen but do not use the oxygen for respiration; obtain energy from fermentation
|
|
Homofermentative
|
Only product is lactic acid
|
|
Heterofermentative
|
Products are ethanol, CO2 and lactic acid
|
|
Lactic Acid Bacteria
|
> Ferment sugar to produce lactic acid
> aerotolerant anaerobes > most catalase negative Ex. Streptococcus, Lactococcus, Lactobacillus |
|
Production of Yogurt from Milk
|
fermentation
Starter culture of Streptococcus produces acid, at pH of 6 Lactobacillus grows, at pH of 5 Streptococcus ceases to grow |
|
MRS medium
|
used to enrich for Lactobacillus
selective due to low pH |
|
Lactobacillus Isolation Steps
|
(1) Enrichment - MRS broth
(2) Isolation - MRS plate (3) Characterization - Gram stain and catalase test |
|
Formation of Biofilms (3 steps)
|
(1) Attachment
(2) Colonization: polysaccharide production, cell communication (3) Development |
|
Quorum Sensing
|
communication of cells in biofilms
homoserine lactone: biofilm cells produce; it builds up to certain level, causes response from neighboring cells (ex. release of an enzyme, recruitment to the biofilm) |
|
Virus
|
• Obligate intracellular parasite
• Contain DNA or RNA within the capsid (protein) • Host specific |
|
Stages in a Viral Infection
|
(1) Attachment
(2) Injection (3) Viral Synthesis (4) Viral Assembly (5) Release of Virions |
|
Plaque
|
clearing within lawn of bacteria caused by cell lysis due to viral infection
|
|
Darkfield and Phase Contrast Microscopy
|
Types of light microscopy
> allow you to see motile, living cells with sufficient contrast without staining Wet Mount– view living cells, no staining, no procedure other than putting coverslip on slide |
|
Selective Medium
|
selects for a bacteria and does not allow other to grow
|
|
Differential Medium
|
allows differentiation between different bacteria
|
|
Which organism studied ferments mannitol and produces coagulase?
|
Staphylococcus aureus
|
|
What were the two Staphylococci studied and how were they identified?
|
Staphylococcus aureus = yellow on MSA (mannitol salt agar + phenol red)
Staphylococcus epidermidis = pink |
|
Coagulase
|
enzyme which converts fibrinogen to fibrin causing plasma to clot; virulence factor
|
|
manifestations of hypothyroidism - myxedema
|
puffy face, enlarged tongue, hoarse/husky voice, pleural effusion
|
|
Symbiosis
|
intimate relationship between 2 dissimilar organisms
|
|
What two organisms were involved in a commensalistic relationship?
|
Clostridium sporogenes (obligate anaerobe)
+ Staphylococcus epidermidis (facultative anaerobe) |
|
Mutualism
|
both benefit, necessary for survival
Ex. Legumes and Rhizobium |
|
Commensalism
|
one benefits, other unaffected
Ex. C. sporogenes and S.epidermidis |
|
Synergism
|
both benefit, not necessary for survival
|
|
Parasitism
|
one benefit, other hurt
|
|
Antagonism
|
one inhibits growth of another
|
|
Leghemoglobin
|
iron-containing heme binds O2 in nodule
> gives nodules pink color |
|
Root Nodulation
|
(1) bacteria attaches to root hair (polysaccharide on bacteria w/ lectin on hair)
(2) infection thread (3) stimulate root cell rapid division |