Lab Quiz 2 Flashcards
refers to the information about the metabolism of bacteria
Biologic Characters
the chemical reactions that occur within all living organisms
metabolism
proteins that catalyze biological reactions
enzymes
the majority of enzyme which function inside a cell
endoenzymes
many bacteria make these enzymes, which are released from the cell to catalyze reactions outside the cell
exoenzymes
chemical reactions that release energy from the decomposition of complex organic molecules
catabolism
organic molecules that contain carbon, hydrogen, and oxygen in the ration (CH2O)n
carbohydrates
simple sugars containing 3-7 carbons
monosaccharides
composed of 2-20 monosaccharide molecules
oligosaccharides
the most common oligosaccharide
disaccharides
consist of 20 or more monosaccharide molecules
polysaccharides
Exoenzymes are mainly _________ that leave the cell and break down, by the addition of water, large substrates into smaller components, which can then be transported into the cell.
hydrolytic enzymes
hydrolyzes the polysaccharide starch into smaller carbohydrates
amylase
a monosaccharide that can be released by hydrolysis
glucose
chemical reaction that requires the presence of molecular oxygen
oxidative catabolism
The presence of an _____ is determined by looking for a change in the substrate outside a bacterial colony.
exoenzyme
chemical reaction that does not require oxygen but may occur in its presence
fermentative catabolism
nutrient semisolid agar deep containing a high concentration of carbohydrate and a low concentration of peptone
OF medium
In OF medium, the ____ will support the growth of bacteria that don’t use the carbohydrate.
peptone
OF medium contains the indicator ______, which turns _____ in the presence of acids, indicating _____ of the carbohydrate.
OF medium contains the indicator bromthymol blue, which turns yellow in the presence of acids, indicating catabolism of the carbohydrate.
________, caused by he use of the peptone and not of carbohydrate, are indicated by a dark blue color due to ________ production.
Alkaline conditions, caused by the used of peptone and not of carbohydrate, are indicated by a dark blue color due to ammonia production.
If the carbohydrate is metabolized in both tubes, _____ has occurred.
If the carbohydrate is metabolized in both tubes, fermentation has occurred.
Many carbohydrates– including monosaccharides such as _____, disaccharides such as _____, and polysaccharides such as _____ – can be fermented.
glucose, sucrose, startch
used to detect acid and gas production from carbohydrates
fermentation tube
fermentation that results in acid production will turn the indicator ____ (pH of ___ or below)
yellow, 6.8
during prolonged incubation periods (>24 hrs) many bacteria will begin growing _____ on the peptone after exhausting the carbohydrate supplied, causing ____ of the indicator and turning it red because of _____ production.
oxidatively, neutralization, ammonia
used to distinguish organisms that produce large amounts of acid from glucose and organisms that produce the neutral product acetoin
MRVP broth
MRVP medium in a glucose-supplemented nutrient broth used for what two test?
methyl red (MR) test and Voges-Proskauer (V-P) test
If an organism produces a large amount of organic acid from glucose, the medium will remain ___ when methyl red is added in a _____ MR test, indicating that the pH is ______.
red, positive, below 4.4
Methyl red is ______ between pH 4.4 and 6.0
orange-red
If _____ products are produced, methyl red will turn yellow, indicating a pH _____.
neutral, above 6.0
The production of _____ is detected by the addition of potassium hydroxide and alpha-maphthol.
acetoin
If acetoin is present the upper part of the medium will turn ____; a negative V-P test will turn the medium _______.
red, light brown
Bacteria with the enzyme _____ can break down _____ to from pyruvate, which can be reduced in fermentation.
citratelyase, citrate
The indicator ______ changes to blue when the medium is alkalized, indicating a _____ citrate utilization test.
bromthymol blue, positive
large organic molecules
proteins
subunits that make up a protein
amino acids
Amino acids bond together by _____ forming a small chain (_____) or a larger molecule (______).
peptide bonds, peptide, polypeptide
Bacteria can hydrolyze the _____ or ______ to release amino acids
peptides, polypeptides
used primarily in anabolic reactions
amino acids
large protein molecules, such as _____, are hydrolyzed by _____, and the smaller products of hydrolysis are transported into the cell.
gelatin, exoenzymes
_______ dissolves in warm water (_____), solidifies (gels) when cooled below _____, and liquefies (sols) when heated to _____.
Nutrient gelatin, 50 C, 25 C, 25 C
exoenzyme that hydrolyzes gelatin
gelatinase
protein in milk
casein
consists of skim milk and the indicator litmus
litmus milk
Litmus milk medium is opaque due to ____ in colloidal suspension and the litmus is ____.
casein, blue
hydrolysis of the milk proteins
peptonization
Litmus milk is also used to detect _____, because litmus turns pink in the presence of acid.
lactose fermentation
Excessive amounts of acid will cause ______ of the milk
coagulation (curd formation)
_________ will result in an alkaline (purple) reaction of litmus milk.
catabolism of amino acids
Some bacteria can _____, causing the litmus indicator to turn white in the bottom of the tube.
reduce litmus
waste product of protein digestion and is excreted in the urine
urea
enzyme that liberates ammonia from urea
urease
contains peptone, glucose, urea, and phenol read. The pH of the prepared medium is 6.8 (phenol red turns yellow)
urea agar
During incubation in urea agar, bacteria possessing urease produce _____, which _____ the pH of the medium, turning the indicator _____ at pH ____
ammonia, raises, fuchsia, 8.4
After hydrolysis, the pH of urea agar is _____
high (basic)
After hydrolysis, gelatin will _____ at 22 C
liquefy
the removal of an amino group
deamination
removal of carbon dioxide from an amino acid
decarboxylation
enzymes that remove hydrogen sulfide H2S from the sulfur-containing amino acids: cysteine and methionine
desulfhydrases
performed by inoculating a bacterium into tryptone broth and detecting indole via the addition of dimethylaminobenzaldehyde (_____)
indole test, Kovacs reagent
a single culture medium in which motility, indole production, and ornithine decarboxylase activity can be determined
MIO
were developed as a means of separating members of the Enterobacteriaceae (enterics), particularly the coliforms, to determine whether water was contaminated with sewage
IMViC test
I in IMViC
indole production from tryptophan
M in IMViC
methyl red test for acid production from glucose
V in IMViC
Voges-Proskauer test for production of acetoin from glucose
C in IMViC
use of citrate as the sole carbon source
have been developed that provide a large number of results from one inoculation
rapid identification methods
generally, ___ kills microbes; ____ inhibits microbial growth
heat, cold
name the 5 optimal growth ranges
psychrophilic, psychrotrophic, mesophilic, thermophilic, and hyperthermophilic
0C-20C
psychrophilic
20C-30C
psychrotrophic
25C-40C
mesophilic
45C-65C
thermophilic
80C and higher
hyperthermophilic
denatures enzymes, dehydrates microbes, and kills by oxidation effects
dry heat
Standard application of dry heat in a hot-air oven is _____ for ___ hours.
170C, 2
microorganisms that are more or less permanent in the body
normal microbiota
microbes that are present in the body only for days or weeks
transient microbiota
discovered the importance of handwashing in preventing disease and the incidence of puerperal fever
Ignaz Semmelweis
Less _____ occurred in patients attended by midwives, who did not touch cadavers
puerperal sepsis
single most important procedure for preventing healthcare-associated infections
handwashing
3-5 minutes of scrubbing with an antimicrobial soap will remove _____
transient microbiota
disease-producing microorganism
pathogen
organism that harbors the pathogen
host
can be spread either directly or indirectly from one host to another
communicable diseases
cannot be transmitted from one host to another
noncommunicable diseases
the science that deals with when and where diseases occur and how they are transmitted in the human population
epidemiology
diseases that are constantly present in the population. give an example
endemic diseases; pneumonia
When many people in a given area acquire the disease in a relatively short period of time
epidemic disease
first reported patient in a disease outbreak
index case
should include the typical symptoms of patients identified as cases in an outbreak investigation
case definition
disease transmitted when microorganisms are carried on liquid drops from a cough or sneeze. example of direct contact.
droplet infection
transmitted by contact with contaminated inanimate objects
fomites
insects and other arthropods that carry pathogens
vectors
insects carry a pathogen on their feet and may transfer the pathogen to a person’s food
mechanical transmission
continual source of an infection
reservoir
humans who harbor pathogens but who do not exhibit any signs of disease
carriers
compiles data on the incidence of a disease and its method of transmission and tries to locate the source of infection to decrease the incidence
epidemiologist
gives a visual display of the outbreak’s magnitude and time trend
epidemic curve
infected persons who did not come in direct contact with the source, but was exposed by another host
secondary cases
transfers heat energy to the microbial cell more efficiently than dry air, resulting in the denaturation of enzymes
moisture
name the 3 moist heat methods
pasteurization, boiling, and autoclaving
In _____, the temperature is maintained at 63 C for 30 minutes, or 72 C for 15 minutes to kill designated organisms that are pathogenic or cause spoilage
pasteurization
______ (100 C) for 10 minutes will kill vegetative bacterial cells; however, it does not inactivate endospores
boiling
most effective method of moist heat sterilization
autoclaving
15 psi, at 121 C for 15 minutes. usually sufficient to kill endospores and render materials sterile
standard condition for autoclaving
length of time required to kill all bacteria in a liquid culture at a given termperature
Thermal Death Time (TDT)
the temperature required to kill all bacteria in a liquid culture in 10 inutes
Thermal Death Point (TDP)
the time, in minutes, in which 90% of a population of bacteria at a given temperature will be killed
Decimal Reduction Time (DRT, or D value)
in what ways does radiation differ?
in wavelength and energy
x rays and gamma rays are forms of:
ionizing radiation
principal effect is to ionize water into highly reactive free radicals that can break strands of DNA
ionizing radiation
Some ______ wavelengths are essential for biochemical processes.
nonionizing
nonionizing radiation between 15 and 400 nm
ultraviolet (UV)
most lethal wavelengths are sometimes called ____, and are in the _____ range
biocidal, UVC
range 200-290nm and wavelengths corresponding to the optimal absorption wavelengths of DNA
UVC
____ wavelengths 290-320 nm can also cause damage to DNA
UVB
____ wavelengths 320-400 nm are not as readily absorbed and are therefore less active on living organisms
UVA
UV light induces _____ in DNA which results in a mutation
thyamine dimers
repair mechanism where thyamine dimers are exposed to visible light, photolyases are activated; these enzymes split the dimers, restoring the DNA to its undamaged state
light repair, photoreactivation
Another repair mechanism, _______, is independent of light. Dimers are removed by endonuclease, DNA polymerase replaces the nucleotides, and DNA ligase seals the sugar-phosphate backbone
dark repair
types of light for highest energy to lowest
gamma rays, x rays, UV, visible light, infrared, microwaves, radiowaves
visible light color form highest energy to lowest
violet, blue, green, yellow, orange, red
wide variety of chemicals available for controlling the growth of microbes
antimicrobial agents
chemical agents used on inanimate objects to lower the level of microbes on their surfaces
disinfectants
chemicals used on living tissue to decrease the number of microbes
antiseptics
result in bacterial death
bactericidal agents
cause temporary inhibition of growth
bacteriostatic agents
the standard method for measuring the effectiveness of a chemical agent
American Official Analytical Chemist’s use-dilution test
which three strains of bacteria are typically used in the use-dilution test
salmonella enterica, staphylococcus aureus, and pseudomonas aeruginosa
what is the use-dilution test limited to?
bactericidal compounds, it cannot evaluate bacteriostatic compounds
metal rings are dipped into standardized cultures of test bacteria, removed, and dried. rings are next placed into solution of disinfectant, then transferred to a nutrient medium to permit growth of surviving bacteria
use-dilution test
infecting an animal with pseudomonas aeruginosa protects them against what?
bacillus anthracis
(against life), inhibition of a microbes
antibiosis
a substance produced by a microorganism that inhibits other microorganisms
antibiotic
produce nearly 70% of all antibiotis
streptomyces
antimicrobial chemicals used internally, whether natural or synthetic
antimicrobial drugs
disease-causing organism
pathogen
petri plate with agar growth medium is inoculated uniformly. paper disks with various antimicrobial agents are placed on the surface of the agar. the agent diffuses from the paper disk, from an area of high concentration to lower. measured by zones of inhibition
disk-diffusion method
standardized method for agar diffusion methods
Kirby-Bauer test
agar used in Kirby-Bauer test that allows the antimicrobial agent to diffuse freely
Mueller-Hinton agar
The ______ of an antibiotic is determined by testing for bacterial growth in dilutions of the antibiotic in nutrient broth.
minimum inhibitory concentration (MIC)
eukaryotic cells that can be unicellular or multicellular, and obtain nutrients by absorbing dissolved organic material through their cell walls and plasma membranes.
fungi
Fungi, with the exception of ____, are aerobic
yeasts
generally grow better in more acidic conditions and tolerate higher osmotic pressure and lower moisture. larger than bacteria
fungi
nonfilamentous, unicellular fungi that are typically spherical or oval in shape. frequently found on fruits and leaves as white powdery coating.
yeasts
when buds fail to detach themselves in yeast, a short chain of cells forms
pseudohypha
multicellular filamentous fungi
molds
macroscopic mold colongy
thallus
mass of strands that forms the thallus
mycelium
each strand of a mold
hypha
strands of mold that grow in or on the surface of the growth medium
vegetative hyphae
aerial hyphae that originate from the vegetative hyphae
reproductive hyphae
produced by reproductive hyphae
spores
cross wall that separates individual mold cells
septum
hyphae that contain a cross wall
septate hyphae
hyphae that lack septa and are continuous mass of cytoplasm with multiple nuclei
coenocytic hyphae
fungi are classified into phyla based on similarities in their ___
rRNA
fungus-like algae
oomycota
motile asexual spores formed by fungus-like algae
zoospores
members of phylum are saprophytic molds that have coenocytic hyphae
zygomycota
obtains its nutrients from dead organic matter, and usually do not cause disease
saprophyte
zygomycota spore sac
sporangium
zygomycota asexual spores formed inside the spore sac
sporangiospores
zygomycota sexual spores formed by the fusion of two cells
zygospores
include molds with septate hyphae and some yeasts. called sac fungi
ascomycota
ascomycota sexual spores
ascospores
ascomycota spore sac
ascus
saprophytic molds (penicillin, aspergillus) usually produce _____ asexually
conidiospores
include the fleshy fungi, or mushrooms
basidiomycota
basidiomycota sexual spores
basidiospores
club-shaped stalk that produces sexual spores in basidiomycota
basidium
majority of the fungi classified, few are pathogens
saprophytes
selective medium commonly used to culture fungi, has low pH that inhibits growth of other organisms, and simple nutrients
sabouraud agar
nutrients in sabouraud agar
glucose and peptone
secreted by oil glands and inhibits bacterial growth
sebum
most bacteria on the skin are _____ and _____
gram-positive, salt-tolerant
selective media for salt-tolerant organisms
mannitol salt agar
mannitol salt agar is differential in that mannitol-fermenting organisms will produce acid, turning the indicator in the medium _____
yellow
enzyme that clots the fibrin in blood
coagulase
which pathogen produces coagulase?
staphylococcus aureus
