Biol 1020 lab final
instrument used for spreading microorganisms across a streak plate.
Inoculation loop
is a bacteriostatic, narrow-spectrum antibiotic that targets DNA gyrase in some Gram-positive bacteria.
Novobiocin
The mold that Alexander Fleming observed preventing bacterial growth was _____. -Aspergillus -Streptococcus pyogenes -Penicillium notatum -None of the above
Penicillium notatum
is commonly used as a pH indicator in carbohydrate fermentation tests.
Phenol red-turns yellow in acidic solutions
Single-celled fungi used for studies involving fermentation, genetics, and aging.
S. cerevisiae
Normal flora bacteria used for studies involving osmotic pressure, antibiotic resistance, and biofilms.
S. epidermidis
_____ stains Gram-negative bacteria pink. -Crystal violet -Iodine -Safranin -All of the above
Safranin
A positive Voges-Proskauer test appears as _____. -solid red media -solid yellow media -a red layer atop yellow media -None of the above
a red layer atop yellow media
The measure of the light intensity absorbed by a sample
absorbance
Methyl red is a pH indicator that turns red in _____ conditions. -acidic -neutral -basic -None of the above
acidic
contains negatively charged chromophores
acidic stain
optimally grow in pH between o and 5.5
acidophiles
Metabolic process resulting in oxygen and peroxide by-products
aerobic respiration
esults in metabolites (by-products) that include oxygen ions and peroxides. These metabolites are chemically reactive and can cause damage to cell structures.
aerobic respiration
Solid media used to isolate microbes
agar plate
_____ optimally grow at a pH between 8.0 and 11.5. -Acidophiles -Alkaliphiles -Halophiles -All of the above
alkaliphiles
optimally grow at pH between 8.0 and 11.5
alkaliphiles
1. Aseptic technique includes _____ . -working quickly and efficiently around open media containers -not talking or breathing over open media containers -washing hands before and after working with media -All of the above
all of the above
4. The inoculation loop must be sterilized _____ when creating a streak plate. -before use -between use in each quadrant -after completing all quadrants -All of the above
all of the above
4. _____ is an example of a direct stain. -Crystal violet -Methylene blue -Safranin -All of the above
all of the above
A _____ is an example of a fomite. -doorknob -tissue -used needle -All of the above
all of the above
Bacteria move by _____. -flagella -axial filaments -slime secretions -All of the above
all of the above
Food may become contaminated by coming into contact with microbes in the _____. -soil -irrigation water -digestive tract -All of the above
all of the above
Mixed-acid fermentation produces _____. -acetic acid -ethanol -hydrogen gas -All of the above
all of the above
Slides should be rinsed after applying _____ during the Gram staining process. crystal violet iodine decolorizer All of the above
all of the above
The _____ is a biochemical test used to determine the identity of an unknown microbe. -methyl red test -Voges-Proskauer test -catalase test -All of the above
all of the above
When transferring microbes from a broth to a plate, the inoculation loop should be sterilized _____. -before placing in broth -after spreading microbes on the agar surface -prior to disposal -All of the above
all of the above
____ is a cause of foodborne illness. -Cross contamination -Endotoxin exposure -Improper hand washing -All of the above
all of the above
____ is a genus that produces antibiotics. -Bacillus -Cephalosporium -Streptomyces -All of the above
all of the above
_____ are responsible for the indirect transmission of disease. -Airborne droplets -Fomites -Vectors -All of the above
all of the above
_____ are used to maintain safety in packaged and prepared foods. -Butchering standards -Pasteurization procedures -Product recalls -All of the above
all of the above
_____ is a common, harmless microbe used in laboratory studies. -Escherichia coli -Saccharomyces cerevisiae -Staphylococcus epidermidis -All of the above
all of the above
_____ is a factor that limits the distribution of microbes. -Temperature -Oxygen availability -pH -All of the above
all of the above
_____ is a form of functional media used to identify unknown microbes. -Differential media -Enriched media -Selective media -All of the above
all of the above
_____ is a pathogenic bacteria associated with foodborne illness. -Campylobacter -Listeria -Salmonella -All of the above
all of the above
bacteria with a single flagellum at each end
amphitrichous
single flagellum at each end are called
amphitrichous
Agent naturally produced by microorganisms.
antibiotic
Agent artificially synthesized or manipulated from other products.
antimicrobial
acidic stains color what
background or environment
Agent that kills bacterial upon exposure.
bactericidal
causes each of cells
bactericidal
Agent that slows the growth of bacteria.
bacteriostatic
causes inhibition of growth of cells, not death
bacteriostatic antibiotics
contains positively charged chromophores
basic stain
Asexual reproduction resulting in two daughter cells
binary fission
Identifies metabolic properties of microbes
biochemical test
are designed to identify various metabolic properties of different bacteria species. More importantly, these tests, in conjunction with taxonomy, can lead to the unambiguous identification of an organism.
biochemical tests
1. Agar plates should be labeled on the _____.
bottom
_____ is a positive result for catalase testing. -Bubbling peroxide -Red media -Yellow media -None of the above
bubbling peroxide
Anaerobic metabolism that produces acetoin
butanediol fermentation
Liquid media used to increase the number of microorganisms.
Broth
Binds with bacterial ribosomes to prevent cell growth and cell division.
Gentamicin
Bacteria that live in oxygenated environments produce the enzyme ________ to neutralize the harmful effects of hydrogen peroxide.
catalase
Enzyme that mediates the breakdown of hydrogen peroxide
catalase
anaerobic microbes generally lack what enzyme
catalase
Bacteriocidal agents kill bacteria by _____. -cell wall lysis -inhibiting ribosomal activity -preventing cell division -All of the above
cell wall lysis
Colored ions in a stain
chromophores
The charge of _____ determines how dyes interact with bacterial cells during staining. -chromophores -plasma membranes -porins -None of the above
chromophores
A spherical bacteria with a diameter of approximately 0.5 µm
coccus
A viable plate count is a method of calculating the number of cells in a dilution by the counting the number of _____ on agar plates. -cells -colonies -species -All of the above
colonies
Clump of genetically identical microorganisms.
colony forming unit
Describes individual colonies on a plate's surface
colony forming unit
Acidic stain repelled by the cell's surface
congo red
_____ are asexually-produced spores of the Penicillium fungus. -Aspergillus -Bacillus -Conidia -None of the above
conidia
condition passed from person to person
contagious disease
A spreader is used when inoculating a Kirby-Bauer diffusion plate to _____. -isolate individual bacteria colonies -create a uniform bacterial lawn -confine bacteria to one section of the plate -None of the above
create a uniform bacterial lawn
_____ is the transfer of bacteria from one food item to another. -Cross contamination -Intoxication -Pasteurization -All of the above
cross contamination
this dyes all bacterial cells, regardless of peptidoglycan thickness
crystal violet
2. Aseptic techniques are necessary to _____. a. maintain safety b. isolate pure cultures c. prevent the spread of unwanted microbes d. All of the above
d. all of the above
Bacteriostatic antibiotics cause an inhibition of growth rather than cell lysis and death. True False
death
_____ washes dyes from Gram-negative bacteria. -Crystal violet -Iodine -Decolorizer -None of the above
decolorizer
dehydrates the Gram-positive cell wall, trapping in dyes; decolorizer washes dyes from the gram-negative bacteria
decolorizer
_____ media contain an indicator that enables differences between microbes to be visualized. -Differential -Enriched -Selective -All of the above
differential
enable many types of microbes to grow; however, differential media contain an indicator that enables differences between microbes to be visualized.
differential media
Two or more dyes are used. Cell morphology can be described and identification of the structural components (composition of the cell wall and other cell features like flagella, capsules, or endospores) is possible.
differential stain
A dye that stains only the cell leaving the background colorless
direct stain
A type of simple stain; only the bacterial cell becomes colored, leaving the background or external environment clear and colorless
direct stain
basic dyes are used for what. give examples
direct stains; crystal violet, methylene blue, safranin, basic fuchsin and lamachite green
occurs when a pathogen is passed immediately from one person to another via direct contact, such as a hand shake or by kissing.
direct transmission
disruption of the normal state that impairs bodily structure and function
disease
Sterile swabs should be moistened with _____ before collecting microbes from the surface of food items. -distilled water -isopropyl alcohol -undiluted bleach -All of the above
distilled water
Sterile swabs should be moistened with _____ before sampling potential fomite sources in the home. -distilled water -isopropyl alcohol -pure bleach -All of the above
distilled water
are supplemented with essential growth factors for organisms that do not grow well on typical media.
enriched media
The number of individuals doubles each generation
exponential growth
In binary fission, bacterial cells grow _____. -exponentially -linearly -negatively -None of the above
exponentially
A microbe that produces clear broths when tested at 7% and 15% NaCl is considered a halophile. True False
false
All vaccines contain killed microorganisms. True False
false
Fermentation occurs when carbohydrates are broken down aerobically. True False
false
Microbes are only found growing at temperatures between 0°C and 100°C. True False
false
Microbes do not thrive in extreme environments such as hydrothermal vents and alkali pools. True False
false
Most microbes associated with food are harmful to humans. True False
false
S. epidermidis produces turbid motility gels after incubation indicating that it is non-motile. True False
false
To create a series of dilutions, an identical volume of stock (undiluted) solution is added to each of the dilution test tubes. True False
false
Unwashed vegetables possess the same numbers of microbes than those washed with soap and water. True False
false
Zones of inhibition should be measured after they exceed 25 mm. True False
false
Binary fission is a method of sexual reproduction where a single cell (parent cell) will split into four cells (daughter cells). True False
false-Binary fission is a method of asexual reproduction where a single cell will split into two daughter cells.
Gram-positive bacteria have an outer cell membrane containing endotoxins. True False
false-Gram-negative bacteria have an outer cell membrane lacking endotoxins.
Heat fixing is required for the negative staining process. True False
false-Heat fixing is not used in negative staining, only direct staining.
Resistant bacteria will exhibit a large zone of inhibition during a Kirby-Bauer diffusion test. True False
false-Resistant bacteria will exhibit no zone of inhibition during a Kirby-Bauer diffusion test.
Streak plating is performed by pouring broth onto agar plates. True False
false-Streak plating is performed by spreading a bacterial sample on the surface of an agar plate with an inoculation loop.
The effective zone of inhibition is the same for all antibiotics. True False
false-The diameter of the zone is dependent on the sensitivity of a microorganism to a particular antibiotic and the physical properties of the antibiotic itself.
A pure plated culture should exhibit colony forming units with two or more morphologies. True False
false-should be identical morphologies
is the conversion of pyruvic acid (the by-product of glycolysis), into an acid with or without the production of gas.
fermentation
flame is used to kill the bacteria and firmly affix the cells to the slide. when is this used?
fixation process; only in direct stains
A _____ is a non-moving object responsible for the indirect transmission of disease. -fomite -vaccine -vector -All of the above
fomite
is a simple carbohydrate found in fruits and vegetables.
fructose
are often used to determine the identity of unknown microbes, and come in several forms. See Figure 1. Three of the primary forms are selective, differential, and enriched.
functional media
Tryptic Soy Agar (TSA) is a _____ media. -general purpose liquid -selective liquid -general purpose solid -None of the above
general purpose solid
is a simple carbohydrate produced by plant photosynthesis and from the metabolism of glycogen in animals
glucose
Penicillin targets what
gram positive bacteria
have a thin cell wall comprised of a single layer or sheet of peptidoglycan sandwiched between an outer and inner cell membrane. The thin cell wall is only cross-linked in one dimension and is flexible but more susceptible to lysis.
gram-negative cells
Gentamicin is synthesized by a _____. -Gram-negative bacteria -Gram-positive bacteria -black mold -None of the above
gram-positive bacteria
have a thick outer cell wall composed of a mesh-like polymer calledpeptidoglycan, adjacent to an interior plasma membrane. See Figure 7. Teichoic acids are only found in the cell wall of this
gram-positive cells
_____ are microbes that require a high salt concentration for growth. -Acidophiles -Alkaliphiles -Halophiles -None of the above
halophiles
require high salt concentration fro growth
halophiles
Catalase neutralizes the harmful effects of _____. -hydrogen peroxide -butanediol -acetoin -None of the above
hydrogen peroxide
_____ solutions can lead to cell shrinkage and eventual death. -Hypertonic -Hypotonic -Isotonic -None of the above
hypertonic
_____ solutions can lead to microbial cell swelling and rupture. -Hypertonic -Hypotonic -Isotonic -None of the above
hypotonic
-the pathogen is transferred to a fomite, a non-moving object such as a doorknob, tissue, or used needle. ● The pathogen becomes airborne via water droplets produced by coughing or sneezing. ● The pathogen is transported by a vector, a living organism such as a mosquito, fly, or tick.
indirect transmission
Condition caused by viruses, bacteria, parasites, and fungi
infectious disease
ingestion of microbial secretions resulting in foodborne illness
intoxication
iodine reacts with crystal violet, forming a complex that allows dyes to better adhere to the bacterial cells
iodine
contains microorganisms that have been destroyed (killed)
killed vaccine
The outer cell membrane also contains specialized molecules or proteins unique to Gram-negative cells called __________hich are endotoxins that produce reactions such as fever or shock in Gram-negative infections
lipopolysaccharides (LPS)
pathogenic microbe present on improperly washed raw vegetables
listeria
contains agents that resemble pathogens that are often either a weakened form of the pathogen or some of its molecular components, such as toxic proteins.
live attenuated vaccines
bacteria with numbers flagella at one end are described as what
lophotrichous
bacteria with numerous flagella at one end
lophotrichous
The products of mixed-acid fermentation _____ the pH of buffered media. -lower -raise -neutralize -None of the above
lower
is crystalline alcohol produced by many plants.
mannitol
Biochemical tests are designed to identify _____ properties of microbes. -morphologic -metabolic -motility -All of the above
metabolic
Anaerobic metabolism that produces acids, alcohol, and gases
mixed acid fermentation
an anaerobic metabolic process that produces lactic acid, acetic acid, ethanol, carbon dioxide and hydrogen gas.
mixed-acid fermentation
Penicillin is produced by a _____. -bacteria -mold -virus -All of the above
mold
A _____ bacteria has a single flagellum.
monotrichous
Bacteria cells with a single flagellum are termed
monotrichous
self-propelled motion
motility
gel that prevents the diffusion of some microbes
motility media
To determine the number of CFUs in the original culture, the number of colonies on the viable plate is _____ the total dilution factor of that plate. -added to -multiplied by -divided by -None of the above
multiply
are active against a select group of bacterial types and are used to treat specific infections when the causative organism is known.
narrow spectrum antibiotics
A type of simple stain; the cell is unstained and appears as a bright, often colorless object against a dark-stained environment.
negative stain
acidic stains are used for what? give examples
negative stains; Congo red, India ink, nigrosin
A microbe that only produces turbid broths in pH tests at pH 7 is considered a(n) _____. -acidophile -alkaliphile -neutrophile -None of the above
neutrophile
microorganisms that grow best in a pH of 7 and maintaining a pH in their cytoplasm between 6.8 and 7.4
neutrophiles
Motility media prevents the diffusion of _____ microbes. -motile -non-motile -monotrichous -All of the above
non-motile
microbes commonly present in or on an organism that are normally not harmful
normal flora
targets DNA gyrase, preventing DNA replication within a cell.
novobiocin
refers to the concentration of solutes within a solution.
osmolarity
rapid heating and cooling of a liquid to reduce microbial numbers
pasteurization
A _____ is a microscopic agent that causes disease. -pathogen -fomite -vector -All of the above
pathogen
Disrupts cell wall stability, eventually leading to cell lysis.
penicillin
Mesh-like polymer present in bacteria cell walls
peptidoglycan
Penicillin disrupts the formation of bacterial cell walls by inhibiting the formation of _____ cross-links. -porin -protein -peptidoglycan -None of the above
peptidoglycan
The methyl red test detects a microbe's ability to _____. -perform mixed-acid fermentation -perform butanediol fermentation -respire aerobically -All of the above
perform mixed-acid fermentation
_____ bacteria have flagella distributed all over the surface of the cell. -Amphitrichous -Monotrichous -Peritrichous -All of the above
peritrichous
flagella distributed all over the cell are called what
peritrichous
Oxygen ions and _____ are metabolites of aerobic respiration that can damage cell structures. -alcohols -peroxides -mixed acids -None of the above
peroxides
Red-stained media is a _____ result for the methyl red test. -positive -negative -inconclusive -None of the above
positive
A microbe produced positive methyl red results and negative Voges-Proskauer results. It can be concluded that the microbe _____. -respires aerobically -produces mixed acids but does not use the butanediol pathway -uses the butanediol pathway but does not produce mixed acids -None of the above
produces mixed acids but does not use the butanediolh pathway
Gentamicin binds with bacterial _____. -ribosomes -cell walls -mitochondria -All of the above
ribosomes
pathogenic microbe responsible for the majority of reported foodborne illeness
salmonella
____ media contain agent(s) that prohibit the growth of some microbes. -Differential -Enriched -Selective -All of the above
selective
agents that prohibit the growth of some microbes
selective media
contain agent(s) that prohibit the growth of some organisms, thus selecting or allowing the growth of other organisms.
selective media
One dye is used to directly stain the bacterial cell or the background. Cell shape, size, and arrangement may be determined with simple staining techniques.
simple stain
Motility media is a _____ used to detect bacterial movement. -firm agar -concentrated broth -soft gel -None of the above
soft gel
____ exist only as single cells and do not form clusters or chains. -Bacilli -Cocci -Spirillum -All of the above
spirillum
Motility media is inoculated by _____. -pipeting culture broth onto the media surface -streaking a culture with a loop -stabbing a culture into the media -All of the above.
stabbing a culture into the media
are a group of molecules that run perpendicular to the peptidoglycan sheets and provide structural support.
teichoic acids
A _____ is a substance that stimulates the immune system to produce antibodies. -fomite -vaccine -vector -All of the above
vaccine
is a substance that stimulates the immune system to produce antibodies; proteins that identify and neutralize pathogens and other foreign threats.
vaccine
substance that stimulates the production of antibodies
vaccine
Butanediol fermentation produces _____ acids compared to mixed-acid fermentation. -stronger -weaker -identical -None of the above
weaker
Plates with _____ colonies per plate are used to calcuate CFUs. -10-30 -30-300 -20-100 -None of the above
-30-300
When one bacterial cell undergoes binary fission, there will be _____ cells present on the 5th generation. -5 -8 -16 -None of the above
-16
Performing a 1:8 dilution from the original sample 3 times would produce a dilution of _____. -1:24 -1:512 -1:4096 -None of the above
1:512
A viable plate has a count of 95 colonies produced from 0.125 mL of a 10-4dilution of the original sample. The original contains _____ CFU/mL. -760 -12,000 -7,600,000 -None of the above
7,600,000
1. _____ are rod-shaped becteria 0.5 - 20 µm in length. -Cocci -Bacilli -Spirillum -All of the above
Bacilli
Novobiocin is a bacteriostatic, narrow-spectrum antibiotic that targets _____ in some Gram-positive bacteria. -DNA gyrase -RNA primase -Okazaki fragments -None of the above
DNA gyrase
enzyme necessary for DNA replication
DNA gyrase
6. _____ is a rod-shaped bacteria important to the study of genetics and evolution. -Escherichia coli -Saccharomyces cerevisiae -Staphylococcus epidermidis -All of the above
E. coli
An antibiotic is a synthetic drug produced in a laboratory. True False
False
_____ broth is used to culture microbes for the methyl red and Voges-Proskauer tests. -MR-VP -Phenol red -Nutrient -None of the above
MR-VP
_____ is added to nutrient broth to adjust it to pH 9. -Distilled water -NaOH -HCl -None of the above
NaOH
Rod-shaped bacterial cells linked to form a chain
Streptobacilli
2. _____ are bead-like chains of spherical cells. -Tetrads -Staphylococci -Streptococci -None of the above
Streptococci
test is designed to identify microbes that ferment glucose via the butanediol pathway
Voges-Proskauer test
Basic stains color what
the cytoplasm
2. All equipment and work surfaces should be cleaned with a bleach solution after contacting microbe cultures. True False
true
3. Negative staining results in a colorless cell on a stained background. True False
true
Agar is a solid media used in both slants and plates. True False
true
Although oxygen is required for metabolism in many microbes, it is toxic to other species. True False
true
Butanediol fermentation produces weaker acids than mixed-acid fermentation. True False
true
C. botulinum infections are associated with poor food handling and processing procedures. True False
true
Colder temperatures reduce the reproductive rates of most microbes. True False
true
Controlling the spread of contagion within the home requires the identification of potential fomites. True False
true
Differential staining uses two or more dyes to stain structual components of a cell. True False
true
Gram-positive cells have a thick outer cell wall composed of peptidoglycan. True False
true
Infectious diseases are caused by microscopic agents called pathogens. True False
true
Many types of bacteria have gained resistance to antimicrobials at an astonishing rate. True False
true
Microbe numbers in milk increase the longer it is stored in the refrigerator. True False
true
Morphology can be used to identify microorganisms with or without the use of a microscope. True False
true
Most microbes prefer to grow in environments that are pH neutral and isotonic. True False
true
Motility is an important characteristic for classifying microbes.
true
Motility media is an example of differential media because it enables differences between microbes to be visualized.
true
Novobiocin is a bacteriostatic, narrow-spectrum antibiotic. True False
true
One is six Americans become ill from foodborne pathogens every year. True False
true
Pasteurization reduces microbial numbers by rapidly heating then cooling a liquid. True False
true
Shared beverages are an ineffective mode of indirect disease transmission. True False
true
Surfaces with a high diversity of abundance of microbes should be disinfected frequently. True False
true
The methyl red and Voges-Proskauer tests are typically performed together to differentiate bacteria within the family Enterobacteriaceae. True False
true
Turbidity and flocculence are indicators of microbial growth in liquid media. True False
true
Very acidic or alkaline solutions compromise microbial respiration. True False
true
A _____ is a positive result for bacterial motility when using motility agar. -clear gel -turbid gel -defined stab line -None of the above
turbid gel
E. coli produces a _____ after incubation in motility media. -clear gel -turbid gel -defined stab line -None of the above
turbid gel
A _____ broth after incubation is a positive result when testing for pH and salt tolerances of microbes. -clear -turbid or cloudy -green-colored -None of the above
turbid or cloudy
Cloudiness of a fluid caused by large numbers of particles/organisms
turbidity
_____ is a positive test result when using motility media. -Flocculent growth -Turbidity -Clear media -None of the above
turbidity