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