micro lab final

define Hemolysin

a substance produced by a bacteria that damages/destroys RBC's; virulence factor

At which salt concentration do you expect Vibrio natriegens to grow best? Select one: a. 1.5% b. 7.5% c. 25% d. All of the above e. None of the above Feedback

b. 7.5% ** its a halophile

What is the reagent that serves as the substrate in the catalase test? Select one: a. Oxygen b. Hydrogen peroxide c. Air d. Water

b. Hydrogen peroxide

Choose the best answer to fill in the blank. In order for bacteria to degrade substrates outside the cell in their environment, they must be able to make _______ enzymes. Select one: a. specific b. extracellular c. intracellular d. strong

b. extracellular

Which micropipette will you use to transfer 0.1mL of your final dilution blank bottle to a sterile Petri dish? Select one: a. lemon yellow button labeled .2/20 b. gold button labeled .20/200 c. blue button labeled .100/1000

b. gold button labeled .20/200

To obtain a sample to streak onto the N-free agar, a. obtain a loopful of bacteria from the bottom of the N-free broth culture. b. obtain a loopful of bacteria from the surface of the N-free broth culture. c. obtain a loopful of bacteria from the N-free broth culture after you've swirled and thoroughly mixed the contents

b. obtain a loopful of bacteria from the surface of the N-free broth culture.

Of which type of symbiosis are viruses an example? a. synergism b. parasitism c. antagonism d. commensalism e. mutualism

b. parasitism

If the bacteria can reduce nitrate to ammonia how will you know? Select one: a. there will be bubbles in the Durham assembly b. the broth culture will smell like ammonia c. the broth culture will turn red after the addition of zinc d. the broth culture will turn red after the addition of alpha-naphthylamine acetate and sulfanilic acid

b. the broth culture will smell like ammonia

The indicator organism for fecal contamination cannot grow on EMB agar. True False

False

The only reason why we use a loose cotton plug for the tubes is to allow oxygen to enter the tubes. The organisms we use are aerobic. True False

False

In the process of creating a standard curve, you'll calculate the number of cells for each dilution by multiplying the dilution factor by the cfu/ml of the E. coli culture from bench 1. Select one: True False

True

Organisms like Vibrio fischeri that live in marine waters are halophiles. Select one: True False

True

Plates inoculated with Pseudomonas fluorescens incubate at room temperature. Select one: True False

True

S. epidermidis is a facultative microorganism, so it can grow in environments with or without oxygen. True False

True

Staphylococcus epidermidis is more vulnerable to antibiotics like penicillin than Pseudomonas fluorescens. Select one: True False

True

The IMViC series is useful for identifying microorganisms that are classified as coliforms. True False

True

The Voges-Proskauer test is used to detect acetoin. True False

True

To determine if you have isolated Azotobacter you will perform a capsule stain because Azotobacter is capable of making a capsule. True False

True

To try to identify a coliform isolated on an EMB plate from the Completed test of the MPN techniqe, you will inoculate a set of IMViC media. True False

True

View the dilution scheme for bacteriophage titration in your lab manual. To get a 10-4 dilution of phage, transfer 1mL from a 10-3 phage dilution (tube A) to 9mL of phage buffer. True False

True

When iodine is added to a starch agar plate, agar turns brown everywhere starch is present. -True -False

True

You will inoculate a set of Dubos broths to test for cellulase production by Cytophaga. True False

True

Human pathogens are ________________________. Select one: Psychrophiles (cold) basophiles Thermophiles extreme halophiles Mesophiles

Mesophiles (between thermophile and psychrophile)

What factors are responsible for the effectiveness of antimicrobial agents? Select one or more: contact time concentration corrosiveness acidity

contact time concentration

The oxidase assay tests for the presence of ________. Cytochrome c oxidase is present in oxidase positive organisms. Many oxidase negative organisms are facultative aerobes capable of aerobic respiration but they use a different cytochrome to reduce oxygen.

cytochrome c oxidase. Acinetobacter

Place the terms that describe organisms growth temperature needs in order from coolest to hottest. Select one: a. Thermophile, neutrophile, psychrophile b. Psychrophile, thermophile, mesophile c. Psychrophile, neutrophile, thermophile d. Psychrophile, mesophile, thermophile e. Thermophile, mesophile, psychrophile

d. Psychrophile, mesophile, thermophile

What will you see if Pseudomonas fluorescens is sensitive to chloramphenicol? Select one: a. any size clearing around the disc b. a clearing around the disc of ≤12mm c. a clearing around the disc 13-17mm d. a clearing around the disc ≥ 18mm e. no clearing around the disc

d. a clearing around the disc ≥ 18mm

What type of media will you be using for osmotic pressure experiment? Select one: a. plates with low, medium, high, very high amounts of lipids b. tubes with low, medium, high, very high pH c. plates with low, medium, high, very high amounts of sugar d. plates with low, medium, high, very high amounts of salt

d. plates with low, medium, high, very high amounts of salt

An organism's catalase production gives you information about what? Select one: a. The presence of nitrate reductase in the cell b. Its optimal osmotic environment c. Fermentation properties d. reduction of O2 during respiration

d. reduction of O2 during respiration

Since broth cultures of bacteria can reach high numbers of cells quickly, a series of ___________ is required to obtain a countable plate from a standard plate count.

dilutions

You are using BSL1 species related to 2 genera of human pathogenic bacteria for experiment 8. What are these genera? Select one: a. epidermidis and fluorescens b. aureus and aeruginosa c. Staphylococcus and Streptococcus d. Pseudomonas and Paracoccus e. Staphylococcus and Pseudomonas

e. Staphylococcus and Pseudomonas

What is the indicator used in the peptone iron agar? Select one: a. ferrous citrate b. ferrous sulfide c. ferrous sulfate d. ferric sulfide e. ferric citrate f. ferric sulfate

e. ferric citrate

Which of the following enzymes can hydrolyze proteins into short chains of amino acids? Select one: a. Cellulase b. Amylase c. Catalase d. Helicase e. Superoxide dismutase f. gelatinase

f. gelatinase

-Streptococci vary in their oxygen requirement. Streptococcus pneumoniae is a _________, growing in the presence or absence of oxygen. S. intermedius is _________ and prefers increased CO2 and reduced oxygen tension while other species are _________ which can only grow in the absence of oxygen. To facilitate optimum growth as well as the production of hemolysins, cultures of human isolates of streptococci are incubated in a CO2 incubator or a _______ (Figure 10-2). The candle in the jar is lighted prior to incubation of the jar at 37°C. The flame goes out as oxygen is consumed, resulting in a 5-10% CO2 atmosphere. This enhanced CO2 environment is ideal for human streptococci which are microaerophilic. -An extremely large and diverse population of microorganisms is present in the human mouth. Conditions in the mouth are ideal for bacteria. Up to one liter of saliva is produced per day, the temperature is warm and food is present at regular intervals, satisfying the requirements for growth of an assortment of bacteria. Different populations exist on the tongue, cheeks, teeth, and gums. Bacteria have difficulty attaching to clean tooth enamel. However, within minutes after brushing, a thin film of proteins from saliva coats the tooth. -Within a few hours, several species of Streptococcus begin to attach to the film. If _______ (usually as sucrose) is provided, Streptococcus mutans will break it down into glucose and fructose. S. mutans will then produce a polymer of glucose called dextran. Dextran is a gummy substance that coats the teeth and helps to hold bacteria in place. An accumulation of dextran and bacteria is a biofilm called _________. Streptococci and organisms of the genus Lactobacillus metabolize sugars to produce lactic acid. Lactic acid remains trapped within the dextran/bacterial cell matrix because saliva does not penetrate plaque. Because plaque serves as an "acid-soaked sponge" held against the tooth, the enamel of the tooth may start to decalcify, which permits dental caries or tooth decay to develop.

facultative aerobe microaerophilic obligate anaerobes candle jar sugar dental plaque

Organisms that grow well in hypertonic or high salt solutions are called _______. An example is Vibrio fischeri, which inhabits marine waters and grows optimally in salt concentrations greater than 3%. A few organisms, particularly some Archaea, are _________, thriving in solutions of 15-30% NaCl. Some organisms may grow in relatively high salt concentrations, but grow best at low salt concentrations. These organisms are called _________. An example is Staphylococcus epidermidis, which grows in elevated salt concentrations, but grows best in solutions of less than 1% NaCl. Other organisms are not tolerant of elevated salt concentrations and therefore must live in environments with less than 1% NaCl.

halophiles. extreme halophiles halotolerant.

-Specific terms are used to describe the carbon and energy requirements of living cells. Most prokaryotes require an organic compound of some sort as their sole source of carbon and are termed _________. Carbon is obtained through the breakdown of organic carboncontaining compounds. ________ organisms obtain carbon from the carbon dioxide in the air. -Organisms must also obtain energy for cell functions such as biosynthesis, motility, and transport .________ use light as an energy source. Photosynthesis, which converts light energy to chemical energy, is pigment-associated and is common to plants and some prokaryotes._______ use chemicals as energy sources. If the chemotroph uses an ________ as the energy source, it is called a chemoorganotroph. If the chemotroph uses an _______ as the energy source, it is called a chemolithotroph. Microorganisms catabolize or break down large molecules to obtain energy and smaller carbon-containing compounds for cellular activities. Catabolism can utilize fermentation or respiration (Figure 9-F). ________, the process by which glucose is converted to pyruvic acid, is common to both fermentation and respiration. If oxygen or another terminal electron acceptor is available, respiratory organisms will then utilize the citric acid cycle and an electron transport system to produce water, CO2, and energy in the form of ATP. Fermentative organisms rely upon substrate-level phosphorylation to produce a reduced organic compound, NADH, and a small amount of ATP. ATP is used as a short-term energy for the cell. The NADH returns to get oxidized in glycolysis or in the early steps in the fermentative pathway. The reduced organic compounds are fermentation products released into the environment and may be acids, neutral substances such as alcohol, or CO2 or H2 gases. Fermentation products vary with the organism. The lactic acid bacteria, Lactobacillus and Streptococcus, produce lactic acid from sugars and are used commercially to produce yogurt and cottage cheese from milk. The yeast Saccharomyces produces CO2 and ethyl alcohol from sugar and is used in the baking, beer brewing, and wine producing industry.

heterotrophic Autotrophic Phototrophs Chemotrophs organic compound inorganic compound Glycolysis

what is a plaque

hole in a lawn that result after series of viral infection/lysis

If a cell is placed into a solution that has a lower solute concentration than the interior of the cell, the solution is _______, and water will flow into the cell. Eukaryotic cells, such as red blood cells, lack a cell wall and will swell until they burst when placed in such an environment. Bacterial cells have cell walls and are relatively unaffected by hypotonic solutions. Some water will enter the bacterial cell, but the rigid cell wall will limit the amount of swelling. If a cell is placed into a solution with an osmotic pressure that is equal to that inside the cell (concentration of solutes is equal inside and outside the cell), then there is no effect. Water may flow in and out of the cell, but there is no net flow of water in one direction. This type of solution is called ______. All cells are susceptible to plasmolysis, shown in the figure below, if placed in a hypertonic environment where the solute concentration outside the cell is greater than inside the cell. In a hypertonic solution, water leaves the cell until equilibrium is reached inside and outside the cell, resulting in a loss of water that could be fatal.

hypotonic isotonic

when is water potable?

if it contains less than 2.2 coliforms per 100 ml of water as detected using the MPN technique

As an energy conserving mechanism, some enzymes are produced only if the appropriate substrate is available. These are called _______ or _______ enzymes. Enzymes that are essential to the cell are produced at all times and are called _________ enzymes. Microbiologists study different features of microorganisms in order to identify the microbes, as well as to select organisms with certain characteristics useful for a particular task. To examine the cell size, shape, and arrangement of a bacterium is to study the morphology of that organism. Microbiologists also investigate an organism's metabolic capabilities, which includes an examination of the enzymes it produces and how it reacts biochemically. This type of assessment tells how the organism functions in an environment and is a study of the physiology of that organism.

inducible adaptive constitutive

On EMB agar, E. coli colonies appear.... metallic green Very dark pale pink fish eye colony

metallic green Very dark

On what surface will you be placing the bacteria for the catalase test in lab? Select one: a. plate b. microscope slide c. tube d. bench e. hand

microscope slide

Physicians must be aware of the ________of a drug, how the drug will kill or inhibit the growth of pathogens

mode of action

The pH at which a microorganisms grows best is termed its _______ pH.

optimum

Escherichia coli is placed in a 15% NaCl solution. The net flow of water is _______

out of the cell

The cell ____ confers the bacteria's ability to be unaffected to hypotonic solutions.

wall

What color do you expect the Snyder's test agar to be following inoculation with a high number of Lactobacillus and incubation? a. blue b. blue-green c. yellow d. green

yellow

Covering part of the agar surface protects the cells there from UV exposure. Select one: True False

true

Host-associated microbes are part of the microbiome that lives in and on us. True False

true

Incubate all the pH broths at the temperature required for the organism you used. Select one: True False

true

Pseudomonas putida is oxidase positive. Select one: True False

true

Staphylococcus epidermidis produces bubbles when mixed with hydrogen peroxide, therefore is catalase positive. Select one: True False

true

Use a tongue depressor to help gain better access when obtaining a throat culture. Select one: True False

true

With your lab partner, you will inoculate a gelatin agar plate with both Escherichia coli, Bacillus subtilis and your organism. Select one: True False

true

With your lab partner, you will inoculate a starch agar plate with both Escherichia coli, Bacillus subtilis, and your organism. Select one: True False

true

You will be using a PASCO wireless spectrophotometer for the turbidimetric assay. Select one: True False

true

Based on the pH it grows best at, Saccharomyces cerevisiae would be a Select one: a. Acidophile b. neutrophile c. thermophile d. alkalinophile e. None of the above

Acidophile

A Gram stain would help distinguish between Staphylococcus epidermidis or Staphylococcus aureus growing on an MSA plate? a. cannot be determined b. False c. True

False

A clear area in which there is no bacterial growth around an antibiotic is known as a zone of resistance. Select one: True False

False

Staphylococcus epidermidis tests positive for coagulase production which can be seen by the zone of hydrolysis on a blood agar plate. True False

False

Antibiosis is the symbiotic relationship between two organisms in which there is inhibition, injury or killing of one organisms by the other. Select one: True False

True

C6 solution is a salt free buffer that releases the DNA bound to the spin filter. True False

True

EMB agar is used for the completed test of the MPN series. True False

True

Endospores are extremely resistant to UV that reaches the Earth's surface. Select one: True False

True

A differential medium provides a visible indication of a physical characteristic of an organism. True False Feedback

'False'.

Bromocresol green is a pH indicator in Snyder's test agar that turns yellow when the pH increases. True False

'False'.

If an organism can breakdown cysteine into ammonia, pyruvate and hydrogen sulfide then you will not see a black precipitate along the stab line of peptone iron agar. Select one: True False

'False'.

LSL broth inhibits the growth of non-coliforms. True False

'True'.

N-free broth lacks nitrogen. True False

'True'.

Under ideal conditions, some microorganisms are capable of reaching tremendously large populations in a matter of hours. A loopful of E. coli can grow and divide to reach 109-1010 cells/ml overnight._________ or counting the number of cells in a sample can be useful and achieved in several ways (Table 6-A). A __________employs a specialized type of slide called a ________ or __________ or hemacytometer (Figure 6-A). A sample of broth culture is placed on the counting chamber. Only the bacteria in certain portions of the chamber will be counted. The number of cells counted are then multiplied by a dilution correction corresponding to the area utilized. A direct count includes all cells, both live and dead. In a direct count, individual cells can be counted, including those in clusters, chains, and pairs. A direct count requires some expertise with the dilution aspect of the counting chamber and familiarity with the microscope.

- Enumerating -direct microscopic count -cell counting chamber -hemocytometer

Citrate test - Inoculate Simmons citrate agar slant - _______ is only carbon source -___________ is only nitrogen source -_______is pH indicator (green at pH 7), blue above pH 7 - some microorganisms can utilize ____ as the sole carbon source - bacteria that can do this can also convert ammonia phosphate to ________ and _________

- Sodium citrate -Ammonium Phosphate -Bromothymol blue is pH indicator -citrate - ammonia -ammonia hydroxide

High temperatures kill organisms by Select one: -solidifying lipids in membranes -Causing mutations -Denaturing proteins essential for life. -annealing the DNA

-Denaturing proteins essential for life.

indole test -media used - enzyme ______ breaks down ______ into ______, ______, and ______ -Kovac's reagent: **check for indole production by adding a dropper full of Kozak's reagent--reacts with indole to form red layer at top of broth (+ result)

-1% tryptone broth - tryptophanase -tryptophan -indole, pyruvic acid, and ammonia

-what is an antimicrobial agent? -What are some characteristics of a cidal agent? -what are some characteristics of a static agent?

-A chemical that kills or inhibits the growth of microorganisms -lethal, kills microbs, virucidal, fungicidal, bacteriocidal -inhibits growth, does not kill microbes, virustatic, fungistatic, bacteriostatic

________ are antimicrobial agents that can be applied to skin but are not necessarily safe for ingestion. Ethanol and iodine are examples of commonly used antiseptics. Ethanol is an antiseptic and disinfectant because it is used to clean inanimate objects and can also be used on the skin. ______ are antimicrobial chemotherapeutic agents of microbial origin, often taken orally or given intravenously, used to kill or inhibit the growth of bacteria. Penicillin and streptomycin are examples of antibiotics effective against bacteria. The ________ makes penicillin. The Gram-positive bacterium _______makes streptomycin. Most antibiotics today have a chemical basis in a substance produced by a microorganism, but the substance may have been chemically altered to enhance its antimicrobial activity or reduce the toxic effects to the infected host. For example, penicillin G is the original penicillin made by P. chrysogenum but it is rarely used today because of widespread antibiotic resistance. Semisynthetic penicillins like methicillin, ampicillin, and amoxicillin are used, though bacteria can be resistant to these chemically altered antibiotics too. When evaluating the effectiveness of chemical agents, several factors must be considered. For example, the concentration of the disinfectant and contact time or amount of time it is left on the surface are important. Some microorganisms are sensitive to a low concentration of the antimicrobial agent, while others are sensitive only to high concentrations of the same agent. We refer to these organisms as susceptible or sensitive to the antimicrobial agent. Time is also a factor, and some microorganisms are killed or inhibited with shorter exposure times. Dormant forms, such as bacterial endospores, and thick layers of microbes like biofilms are very resistant to the action of chemical agents being able to survive high concentrations and prolonged exposure. Actively growing microorganisms are the most sensitive to the action of these agents

-Antiseptics -Antibiotics -Penicillium chrysogenum fungus -Streptomyces griseus

________ are used by many microorganisms for locomotion. Although flagella may be found among all three domains of life, the structure of the flagella are quite different. The eukaryotic flagellum is made of_______ (made of the protein tubulin) driven by dynein motor proteins, which move eukaryotic flagella back and forth. _______ is a single-celled eukaryotic green alga with a pair of flagella at one end of the cell each whipping back and forth to move the cell. The prokaryotic flagellum is far more complex. Bacterial and archaeal flagella appear similar in structure superficially, but on closer examination there are subtle structural differences such as the width of the flagella as well as how the flagella use energy. Bacterial flagella are anchored by a complex of proteins in the cell envelope called the ______ or motor. A curved hook connects the basal body to the extracellular component of the flagellum, the filament. The filament is made of _______.

-Flagella - microtubules -Chlamydomonas reinhardtii -basal body -flagellin proteins

-Many species of the genus Streptococcus, which are________, usually in chains, are present in the normal microbiota of healthy humans. The mucus membranes of the mouth and intestines of humans harbor streptococci. Several species of streptococci can cause serious illness and are considered _______. Along with _________, streptococci are known to cause _______ (an infection of the lining around the brain and spinal column), a skin infection called ______, and an assortment of other problems. -Some streptococci, especially the pathogens, are _______ organisms that require enriched media and a controlled atmosphere in order to grow. ________, a nutritious differential medium to which 5% sterile sheep blood has been added after the sterile medium has been tempered (cooled to just above the temperature at which agar solidifies), is excellent for growing streptococci. Blood agar is especially useful for streptococci because it demonstrates ________. Hemolysins are proteins that damage animal cells and can cause them to ________ or break open. If an organism produces a hemolysin, it causes ________ (from the Greek haima for "blood" and lysis for "loosening").

-Gram-positive, catalase-negative cocci -pathogens -strep throat, scarlet fever, and pneumonia -meningitis -impetigo -fastidious -Blood agar -hemolysin production -lyse -hemolysis

The current model for the movement of bacterial flagella is by a "rotary engine" (or "rotary motor") in which a proton gradient (Na+, K+, and Rb+ can also be used) provides the energy to rotate the flagellum. The force to spin the motor proteins can be obtained when protons from the periplasm flow back into the cell through ______, which are located adjacent to the motor. The number and attachment of bacterial flagella can vary among species and is characteristic of a given species. When one or more flagella are attached at the "ends" of the cells, the attachment is considered _____. Polar attachment can take many forms. For example, a single flagellum may be attached at one end of a cell in a _______fashion. When a "tuft" of flagella are attached at one or both ends, the flagellar arrangement is called _______ A bacterium that has one flagella at each end of the cell is said to have ______ flagella. In contrast to the polar attachments, ______flagella can be found at multiple locations of the bacterial cell, not just the ends

-Mot proteins -polar -monotrichous -lophotrichous. -amphitrichous -peritrichous

- what does direct contact cause -what does indirect contact cause

-Mumps virus, HIV, influenza - Hepatitis B, Hepatitis A, etc

Match the description with each organism. D. radiodurans E. coli Bacillus secies

-Thymine dimers most likely formed in this organism but were repaired quickly -Did not survive long UV treatment -Endospores able to survive UV treatment, but not vegetative cells.

__________ is a portion of sunlight that is normally screened by the ozone layer that surrounds Earth. It can be lethal to living cells, especially at wavelengths around 260 nanometers (nm), because this wavelength is readily absorbed by nucleic acids. UV light causes ________ to form within DNA, which can result in mutations or death of the cells. UV radiation can be used to induce mutations. A _______ in the gene(s) for pigment production could result in a colorless colony. Pigments can provide some protection from UV radiation much like the human skin pigment melanin. Other mutations may provide beneficial new characteristics for the organism like the inability to bind an antibiotic that could inhibit the organism's growth. _________ result in death of the cell because the damaged DNA cannot yield the RNA or protein product essential for cell survival. UV radiation can cause death if too many mutations occur and the cell cannot repair the damage in a timely manner. The inability of UV radiation to penetrate restricts its usefulness for eliminating microbes to the cleaning of surfaces or very thin films of liquid. Bacterial endospores survive for decades in soil even when exposed to sunlight. The resistant nature of the spore coat as well as the dehydrated state of endospores render them extremely resistant to UV radiation. Other non-endospore-forming microorganisms may also be resistant to UV radiation. Deinococcus radiodurans is resistant to UV radiation because it has a highly efficient means of repairing the DNA damage induced by UV radiation.

-Ultraviolet radiation -thymine dimers -mutation -Lethal mutations

Select from the following qualities of the cellulase enzyme. Select one or more: degrades starch break Alpha 1, 4 glycosidic bonds break apart a polymer of glucose extracellular enzyme are produced by fungi

-break apart a polymer of glucose -extracellular enzyme -are produced by fungi

confirmed test - medium -selective component -selects for -differential component -explanation -+ result

-brilliant green lactose bile broth -brilliant green and bile -inhibit the growth of noncoliform thereby selecting for coliform -lactose (gas production from lactose makes medium differential) -intestinal bacteria that ferment lactose produce gas (and acid) as byproduct; gas will be visible in Durham tube - gas in Durham tube and turbidity -

-Environmental and water quality microbiologists look for the presence of ________ to assure water safety. Coliforms are ______ rods that produce ______ from ______ within 48 hours of incubation at 35°C. They are part of the normal intestinal microbiota of humans and large animals. ________, a coliform found in large numbers in sewage, survives longer in water than do most intestinal pathogens and is used as the ________ for fecal contamination in the United States. Other coliforms, including ________, may be found in feces but may also be present in the environment and in decaying vegetation which has not been contaminated with feces. -Even though coliforms can be present without the presence of human feces, the ________ is used to indicate sewage pollution. The total coliform count can be indexed by a statistical estimation known as the ________, which relies upon the characteristic of gas production from lactose, which is common to coliforms. The technique is a series of three tests: a_____, a _______, and a ________ test

-coliforms -aerobic or facultatively anaerobic Gram-negative non-spore forming -gas -lactose -Escherichia coli -indicator organism -Enterobacter aerogenes -total coliform count -most probable number (MPN) technique - presumptive -confirmed -completed

-factors affecting the effectiveness of a chemical agent: -effectiveness of an antimicrobial agent is determined by ___________ -what is the zone of inhibition

-contact time and concentration of agent -the size of the zone of inhibition -clear area around antibiotic disc where there is no bacterial growth

disc diffusion method (or Kirby-bauer method) -size of zone of inhibition depends on:

-diffusion rate of the chemical agent into the media -concentration of the bacteria -type of growth medium

completed test -medium -selective component -selects for -differential component -explanation -results

-eosin methylene blue agar (EMB) -eosin and methylene blue dyes -Gram negative bacteria -lactose -lactose fermentors produce acid and gas as byproducts. acid production drops pH around colonies which causes colonies to take up dyes and become dark -gram negative bacteria growing on the plates. if the bacteria are lactose fermentors, the colonies will range in color from somewhat purple to green due to uptake of the dyes

-what does selective media do? -what is an example? -what is differential medium -what is an example

-favors the growth of certain microbes and inhibits competitors -Lauryl Sulfate lactose broth --Lauryl sulfate inhibits Gram positive organisms, therefore selects for intestinal Gram negative bacteria -visible indication of a physiological characteristic -Lauryl Sulfate lactose broth--lactose fermentors cause gas production

cellulase -an Enzyme that hydrolyzes cellulose into _____ to be transported into the cell for ______ - a polymer of _______ -found in _______ -______ is part of the natural cycling of carbon -cellulose degradation: two ways

-glucose -metabolism -glucose -eukaryotic (plants and algae) cell walls -cellulose decomposition -aerobically: cellulase producing bacteria (cytophaga) -anaerobically: members of genus clostridium

Match the type of hemolysis with it's affect on blood cells. -alpha hemolysis -beta hemolysis

-incomplete lysis -complete lysis

define and give example -bacteriocidal -bacteriostatic

-kill bacteria by DNA damage and cell wall lysis, etc. (example, UV radiation, antibiotics) -Inhibit bacteria growth, blocking DNA synthesis, cell wall synthesis etc. Example-plasmolysis, antibiotics

Bacteriophage titration - most phage infections result in the _____ of the host cell, releasing the new ______ -what is a temperate phage - what is lambda

-lysis -viral particles -capable of an alternative cycle called lysogeny -a dsDNA temperate bacteriophage that infects E. coli

MPN technique -the total coliform count can be indexed by a statistical estimation known as the: -the total coliform count is used to indicate: -MPN relies upon the __________, which is common to coliforms -what is the greatest microbial hazard to a water supply? -looking for presence of organism common to human and animal ____ to indicate fecal pollution

-most probable number (MPN) technique -sewage pollution -characteristics of gas production from lactose -contamination with animal or human feces -intestine

Match the following symbiotic relationships with the appropriate example. -lichen -Bacteriodes and E. coli in the human gut -Bdellovibrio and E. coli

-mutualistic -commensalistic -parasitic

label each according to their pH Escherichia coli Propionibacterium acnes Agrobacterium

-neutraphile -Growth at low pH -Alkalinophile

-nitrogen fixation requires the presence of the _______ complex containing two enzymes, _____ and _______- -dinitrogenase reductase is inactivated by _______ -___________ must be able to protect the dinitrogenase reductase enzyme from being inactivated by oxygen -example:

-nitrogen enzyme -dinitrogenase and dinitrogenase reductase -oxygen -Aerobic nitrogen fixing bacteria -Azobacter uses a third protein to reversibly complex to the nitrogenase enzyme complex to conformationally protect it from oxygen inactivation -Azobacter also .....ording alginate capsule

-Some streptococci and many other organisms do not produce hemolysins. These organisms do not cause hemolysis on blood agar, and are called ________. The term gamma (γ) hemolysis is sometimes used to describe this lack of hemolysis. -_______ or α-hemolysis is an incomplete lysis of red blood cells and is seen as a ________ of the red cells and a _________ of the agar around the colony of a-hemolytic bacteria. Alpha hemolysis may be observed more easily if the blood agar plate is held up to a light. The greening of the medium is due to the development of methemoglobin from hemoglobin, the iron-containing molecule in red blood cells which carries oxygen. Many of the species of streptococci that are normally present in the mouth and upper respiratory tract of humans like Streptococcus mutans and Streptococcus sanguinis are α-hemolytic and are collectively referred to as viridans (from the Latin viridis = green) streptococci. Some Lactobacillus species are also α-hemolytic. Streptococcus pyogenes, the pathogen which causes strep throat, scarlet fever, and several other serious illnesses, produces a beta or β hemolysin. Beta hemolysis causes the ________ destruction of the red blood cells and is seen as a clearing around a β-hemolytic colony on blood agar. It should be noted that numerous organisms other than streptococci produce hemolysins including Staphylococcus aureus. Clinical microbiologists utilize hemolysin production as a characteristic for identifying bacteria. The bacteria, however, produce hemolysins to facilitate their growth and survival. The production of a hemolysin causes the release of nutrients, including iron, from animal cells to the bacteria. _______ are structures or substances produced by a microorganism which enhance its ability to cause disease. Bacterial capsules and enzymes such as coagulase or hemolysin are considered virulence factors. The enzyme ________ is another virulence factor produced by pathogenic streptococci. Streptokinase dissolves fibrin clots, which could enhance the organism's ability to invade tissue and cause disease to spread. Purified streptokinase is used therapeutically to dissolve blood clots in some patients.

-nonhemolytic -Alpha -partial clearing -greenish darkening -complete -Virulence factors -streptokinase

Viruses are _______ which must infect an appropriate host cell in order to replicate. Like bacteria, viruses can be transmitted directly from person to person or indirectly with an intermediate object or organism helping to spread the virus. For direct contact, the virus can be transmitted horizontally by __________. Vertical transmission by direct contact involves transmission from mother to fetus or newborn. For indirect contact, the virus can be transmitted by inanimate objects (fomites; ex. Hepatitis B virus), by a vehicle like food and water (ex. Hepatitis A virus), or by a vector (ex. West Nile virus).

-obligate intracellular parasites - physical contact (ex. Mumps virus), sexual intercourse (ex. HIV), or by respiratory droplets through coughing, sneezing and breathing (ex. Influenza virus).

-Water that is safe to drink is called _______ water, while water that is polluted either by chemical contaminants or by microorganisms is unsafe to drink. The greatest microbial hazard to a water supply is contamination with animal or human feces. Many _______ (those that affect the gastrointestinal tract) are transmitted from infected individuals to others by fecally contaminated water. This is a common occurrence in underdeveloped countries where lack of sanitary practices can easily result in contamination of the water supply for hundreds of people. Microbial contamination of water supplies is always a concern following disasters such as earthquakes or floods. Enteric bacterial diseases like ________ (Salmonella typhi), ______ (Vibrio cholerae), and________ (Shigella dysenteriae), viral diseases such as polio and hepatitis, as well as amoebic dysentery are transmitted by ______ contamination. It would be difficult, time-consuming, and expensive to detect the presence of these pathogens in water. It is much more feasible to simply look for the presence of organisms common to human and animal intestines to indicate fecal pollution. If these fecal organisms are present in water, it should not be consumed by humans since it might also contain pathogens like those listed above.

-potable -enteric diseases -typhoid fever -cholera - dysentery -fecal

The __________ is a widely used method for quantifying microorganisms. This technique is also known as a _______ based on the assumption that one living cell will give rise to one colony. Because a colony may actually arise from more than one cell, especially with cells that form clusters, pairs, or chains, organisms are quantified as ________rather than cells per milliliter. Overnight cultures must be serially diluted and aliquots placed in Petri dishes with an appropriate medium. In viable plate counts, several aliquots of each dilution should be plated and incubated. The series of plates is then examined and a_______ plate is selected. A countable plate is one that yields 30-300 colonies. Plates with fewer than 30 colonies provide too few colonies to be statistically significant and give an accurate count. Plates with greater than 300 colonies are not considered valid because they may not have provided adequate nutrients and space for all cells to grow to form colonies. On the countable plate, the exact number of colonies is counted and multiplied by the dilution correction to obtain the number of cfu/ml in the original broth. You have observed that broth cultures become cloudy as microorganisms grow. The presence of microbial cells scatters light, creating ________. As the number of cells in a broth increases, there is a corresponding increase in the turbidity of the solution. A__________ measures the amount of light (600 nm) that passes through a liquid. As the number of cells in the broth increases, the amount of light transmitted through the broth decreases. If turbidity is correlated to viable cell counts and a _______ is established, then turbidity measurements can be used to determine the approximate number of cfu/ml. This allows for a quick determination of cell culture density without having to do a plate count again. However, if the growth conditions are changed, then a new standard curve will have to be made from a new plate count and turbidity measurements.

-standard plate count -viable count -colonyforming units per milliliter (cfu/ml) r countable turbidity spectrophotometer standard curve

give an example of -alpha hemolysis -Beta hemolysis -gamma

-streptococcus pneumoniae -streptococcus pyogenes -enterococcus faecalis

what happens during the -presumptive test -confirmed test -completed test

-water sample was added to Lauryl sulfate lactose (LSL) broth with Durham tubes, incubated -a loopful of LSL broth (+ for gas production) was transferred to brilliant green lactose bile (BGLB) broth to confirm the presence of coliform -a loopful of BGLB broth (+ for gas production) is streaked onto eosin methylene blue (EMB) agar to compete the test for coliforms

View the dilution in your lab manual or the corrected version elsewhere in this quiz to answer the following question: In step 3, 4mL of E. coli is transferred into 1mL of sterile broth. What is the dilution? Select one: a. 1 b. .4 c. .2 d. .6 e. .8

.8

How many tubes of nutrient broth will be inoculated with Staphylococcus epidermidis for the commensalism experiment? Select one: a. 3 b. 1 c. 2

2

What is the minimum number of colonies on a plate considered "countable"? (answer with a number) Answer:

30

How many single-strength lauryl sulfate lactose broths will you inoculate with 1mL of sample water for the presumptive test? a. 3 b. 0 c. 5 d. 10

5

If your countable plate has 50 colonies on it and the dilution factor of the plated sample is 10^-3, What is the cfu/ml of the original sample? Select one: 50 x 10^4 cfu/ml 50000 5.0 x 10^3 cfu/ml 5 X 10^4 cfu/ml 100 cfu/ml

5 X 10^4 cfu/ml **multiply 50 by the reciprocal so by 10^3

The organisms growing on the Mannitol Salt Agar plate are able to tolerate ________ percent of salt.

7.5

On your 10-7 dilution plate, you see 77 plaques. What is the pfu/ml of the original culture? 7.7x10^-8 pfu/ml 7.7x10^7 pfu/ml 7.7x10^8 cfu/ml 7.7x10^8 pfu/ml 7.7x10^-7 pfu/ml 7.7x10^-6 pfu/ml 7.7x10^6 pfu/ml 7.7x10^7 cfu/ml

7.7x10^8 pfu/ml **multiply 77 x 10^7

Which type of hemolysis is indicative of incomplete lysis of red blood cells? Alpha Gamma Beta

Alpha

-________ is one of the proteins present in milk. Casein is a very large protein that is colloidally suspended in milk, and gives milk its opaque appearance and white color. The addition of sterile skim milk to nutrient agar provides a good medium in which to grow microorganisms and to demonstrate the production of ________. If an organism produces this extracellular protease, a clearing will be evident around and under the caseinaseproducing colony. Some microorganisms may be able to grow on milk agar, but will not produce caseinase. There will be no clearing around colonies of these organisms. -The development of solid culture media was essential to early microbiologists. Only with a solid medium could microorganisms be separated into pure cultures. Gelatin, which is a protein extracted from the connective tissue and bones of animals, will gel or solidify below 26°C, but is a liquid at temperatures above 28°C. As Robert Koch found, gelatin was not useful for isolating human pathogens, since it became liquified during the 37°C incubation and because some microorganisms produce extracellular proteases that degrade gelatin.

Casein caseinase

-__________ is one of the proteins present in milk. Casein is a very large protein that is colloidally suspended in milk, and gives milk its opaque appearance and white color. The addition of sterile skim milk to nutrient agar provides a good medium in which to grow microorganisms and to demonstrate the production of ________. If an organism produces this extracellular protease, a clearing will be evident around and under the caseinaseproducing colony. Some microorganisms may be able to grow on milk agar, but will not produce caseinase. There will be no clearing around colonies of these organisms. -The development of solid culture media was essential to early microbiologists. Only with a solid medium could microorganisms be separated into pure cultures. ________, which is a protein extracted from the connective tissue and bones of animals, will gel or solidify below 26°C, but is a liquid at temperatures above 28°C. As Robert Koch found, gelatin was not useful for isolating human pathogens, since it became liquified during the 37°C incubation and because some microorganisms produce extracellular proteases that degrade gelatin.

Casein caseinase Gelatin

Hydrogen sulfide is extremely soluble in water, so that its production cannot be detected in a ________. _________ prepared in "deeps" is an effective medium for demonstrating the production of hydrogen sulfide. This medium contains peptone and ferric citrate. Peptone is a digest of animal proteins that is rich in cysteine. Ferric citrate is an indicator that reacts with hydrogen sulfide to form ferrous sulfide (FeS), a black insoluble precipitate that is very easy to see.

Durham tube Peptone iron agar

what is used as the indicator organism for fecal contamination in the US?

E. coli

For bacteriophage titration, you will add the diluted bacteriophage, the E. coli and the soft agar to the same tube and incubate at 37oC for 20 minutes to allow the phage to attach and infect the host cell. True False

False

For the bacteriophage titration, you will be counting the number of phages that were lysed on an agar plate. True False

False

You can distinguish types of hemolysis on blood agar if you swabbed the entire plate with a throat culture to create a lawn of bacteria. True False

False

What is the gram reaction and cellular morphology of Clostridium sporogenes? a. Gram positive; cocci b. Gram positive; spiral c. Gram positive; rod d. gram negative; spiral e. Gram negative; rod f. Gram negative; cocci

Gram positive; rod

Which of the following are toxic to cells? Select one: a. Peroxidase b. Catalase c. H2O2 d. H2O

H2O2

A microbiologist like a med tech working in a hospital or medical clinic plays an important role in the treatment of infectious diseases. The med tech must first isolate and identify the pathogen, then provide the physician or veterinarian with information that enables him or her to select an appropriate drug for the effective treatment of the disease. In a disc diffusion method such as the ______, filter paper discs saturated with specific concentrations of antimicrobial drugs are placed on the surface of agar plates that have been heavily inoculated with disease-causing isolates. The medium, concentration of the inoculum, and incubation time are specified and the procedure must be followed exactly in a clinical setting. During incubation, the drugs will diffuse from the disc into the medium. The pathogen should grow on the entire surface of the medium, unless it is killed or inhibited from growing by the presence of the drug. If this occurs, a __________ will appear as a clear area in which there is no bacterial growth around the paper disc. The size of the zone is a function of both the antibacterial effect of the drug and the diffusion rate of the drug into the medium. The amount of the drug present at the outer edge of the zone of inhibition is the __________. To determine if the drug is effective for treating the infection, the diameter of the zone of inhibition must be measured and the drug manufacturer's recommendations must be consulted.

Kirby-Bauer method zone of inhibition minimum inhibitory concentration.

For experiment 7B you will use what plating technique? Select one: Pour plate Lawn (A swab of the entire plate) Spread plate Streak for isolation

Lawn (A swab of the entire plate)

-________ and _____ are two macroelements required by all organisms for use in building biological molecules such as nucleic acids, proteins, and phospholipids. Nitrogen and carbon can either be obtained from the air or from organic molecules. Most organisms must obtain their nitrogen from organic sources in the environment like free amino acids, but certain prokaryotes are able to fix gaseous nitrogen from the air. These beneficial prokaryotes are often found in the soil and are responsible for "fixing" nitrogen into usable forms not just for themselves, but also for plants and other bacteria. Carbon can either be obtained from the air as carbon dioxide or from organic sources such glucose and citrate. Organisms that can use (also called "fix") carbon dioxide into other carbon-based molecules are called ________. Plants and many microorganisms can fix carbon dioxide. If an organism cannot fix carbon dioxide, it must use an organic molecule for the carbon it needs to build other carbonbased molecules; these organisms are called _______. Many organisms from microbes to humans are heterotrophs. -Some prokaryotes can fix gaseous nitrogen only while in a symbiotic relationship with plants. For example, _______ and _____ form a symbiotic relationship with legumes. Legumes include clover, soybeans, alfalfa, peas, beans, and peanuts, and the term refers to a plant that bears its seeds in pods. The events leading to root nodulation by Rhizobium are as follows: -The bacterium attaches to the root hair of a legume. A specific polysaccharide on the outer layer of the bacterial cell wall interacts with a lectin, a protein on the surface of the root hair. The bacterium enters the root hair and moves through the root cells by forming an infection thread.

Nitrogen carbon autotrophs heterotrophs Rhizobium Bradyrhizobium

Which of the following statements is/are NOT correct? Select one: a. Extreme halophiles are organisms that may grow at relatively high salt concentrations, but grow best at low salt concentration. b. If you incubate E. coli at low temperature (e.g. 4 degree Celsius), it will die. c. Mesophiles are organisms that grow well at neutral pH. d. If you placed Bacillus species in boiling water, both the vegetative cells and the endospores will survive. e. None of the above statements (A, B, C and D) are correct

None of the above statements (A, B, C and D) are correct

A solution is composed of a substance (solute) dissolved in a solvent. The solvent essential for all living cells is water; most cells are approximately 70% water. ______ describes the flow of water from areas of less solute (and more free solvent) to areas of more solute (and less free solvent) in an attempt to create equilibrium. Osmosis occurs across a semipermeable membrane, such as the plasma membrane of cells. When the concentration of solute is greater outside the cell than inside it, it is called a __________ solution, and water will flow outside the cell. This creates an osmotic pressure on the cell and the cell becomes dehydrated and metabolic activities may stop. The plasma membrane pulls away from the cell wall in a condition called _________. Cells in this type of environment generally do not die, but cease to grow; therefore, a __________ condition results. Salt "cured" fish or sugar and salt "cured" ham represent hypertonic environments in which most microbes cannot grow.

Osmosis hypertonic plasmolysis bacteriostatic

_______ and _______enzymes are made by organisms that produce energy using aerobic respiration. During aerobic respiration, membrane electron transport chain components cycle between the oxidized and reduced state as they donate and accept electrons. This series of redox reactions releases protons outside the membrane (cytoplasmic membrane in bacteria) and provides the energy to build the H+ gradient that leads to ATP production. In aerobic respiration, molecular oxygen serves as the last electron acceptor. To be reduced, oxygen accepts an electron from a protein in the electron transport chain called ________ (Figure 9-A).

Oxidase catalase cytochrome oxidase

-_________ are macromolecules composed of one or more polypetides, long chains of amino acids joined covalently by________. Proteins may be structural, may function as biological catalysts (enzymes), or may serve as nutrients to provide energy and cellular subunits to a bacterium. Nutrient proteins may be too large to be transported into a bacterial cell. They must first be hydrolyzed by ________ into shorter chains of amino acids called _______. Peptides must then be degraded to individual amino acids before the cell can use them for its metabolism. -Many fungi and some bacteria produce extracellular enzymes that _______ proteins. These microorganisms play an essential role in degrading dead animal and plant tissues in the environment, hence serving as the original "recyclers" of nutrients. Some of the degradative enzymes produced by microorganisms have commercial uses. For example, microbially produced proteases are used in laundry detergents and stain removers.

Proteins peptide bonds proteases peptides degrade

In this experiment, several disinfectants, antiseptics, and antibiotics will be evaluated for their ability to kill or inhibit the growth of two bacteria, _________and _________ Paper discs saturated with the chemicals being assayed will be placed onto the surface of the medium inoculated with the organism. The chemical will diffuse into the medium. If the chemical inhibits the growth of the organism, a zone of inhibition will be evident following incubation. The diameter of the zone of inhibition is a function of the solubility, diffusion rate, and effectiveness of the chemical agent. You will also be inoculating a plate with either Streptomyces griseus or Penicillium chrysogenum.After five days of growth, sufficient antibiotic will be made by the Streptomyces or Penicillium to have diffused into the agar. This will allow you to inoculate these plates with other bacteria to see if any are susceptible, to demonstrate antibiosis.

Pseudomonas fluorescens Staphylococcus epidermidis.

-__________ is used to indicate the relative number of lactobacilli in saliva. The pH of this medium is 4.8, which inhibits the growth of most bacteria. _________ serves as the pH indicator in the medium, giving it a blue-green color at pH 4.8. If Lactobacilli are present, they can grow at this low pH and ferment the dextrose in the medium to lactic acid. Acid production causes a color change to yellow as the pH drops. The amount of color change is proportional to the number of lactobacilli present in the saliva and can indicate the likelihood of dental caries.

Snyder's test agar Bromocresol green normal microbiota Gram-positive, catalase-positive cocci virulence factors gastroenteritis staphylococcal food poisoning toxic shock syndrome coagulase

Which microorganisms are halotolerant? Select one or more: a. Staphylococcus epidermidis b. Vibrio natriegens c. Saccharomyces cerevisiae d. Bacillus sphaericus

Staphylococcus epidermidis, Bacillus sphaericus

What serves as the negative control for the caseinase experiment? Select one: a. A place on the plate where hydrochloric acid was not applied. b. The bacteria with a negative result. c. The center of the plate where bacteria was not put. d. There is no negative control for this experiment.

The center of the plate where bacteria was not put.

Another way to discuss temperature and its effects on microorganisms includes their ability to grow at different temperatures. This is different from the ability to survive exposure to certain temperatures. For example, endospores allow species of Bacillus to survive boiling water, but the vegetative cells are killed in most species; therefore, they do not grow in boiling water. _______ grow at high temperatures (45°C-80°C) and are capable of growth in the high temperatures of hot tubs or hot springs and geysers such as Old Faithful at Yellowstone National Park._________grow at temperatures above 80°C, some with optimum growth temperatures above 100°C. ________ grow well at the temperatures comfortable for humans between 20°C-45°C, many with optimum growth temperature at 37°C. ________ grow at low temperatures under 20°C, such as that of a refrigerator or the polar regions of the Earth. All microbes have a permissable range of temperatures over which they grow, with the ________ being that temperature at which they grow most rapidly. As temperatures exceed the optimum, critical enzymes become denatured and thermal destruction of cellular structures, such as cell membranes, and molecules, such as nucleic acids, occurs. Damage from heat is not reversible and will eventually kill the organism. As temperatures drop from the optimum, the rate of cellular enzyme activity diminishes and lipids in the cell membranes begin to solidify, impairing membrane function. Lower than optimum temperatures may inhibit growth, but may not cause cell death. In today's lab, students will test the ability of an organism to survive exposure to a temperature, not grow at that temperature, by subjecting a culture to 0°C (an ice bath), 4°C (a refrigerator), 37°C (a water bath), 60°C (a water bath), and 100°C (a boiling water bath).

Thermophiles Extreme thermophiles Mesophiles Psychrophiles optimum temperature

If you swab the surface of your plate to test the sensitivity of Pseudomonas fluorescens to various antibiotics, then you need to use the antibiotic dispenser labeled "Gram -" for use with Pseudomonas fluorescens. Select one: True False

True

** go back and out stuff about the presumptive and other tests Lauryl Sulfate Lactose broth cultures are used to determine the if a water sample is potable. True False

True

Growth and gas production in 0, 10mL LSL tubes 0, 1mL LSL tubes and 1, 0.1mL LSL tubes. Is the water potable? a. Cannot be determined b. No c. Yes

Yes

Penicillin is the antibiotic produced by Penicillium chrysogenum and its effective against Gram-positive bacteria. The growth of which bacteria will most likely be affected by Penicillium chrysogenum? Select one or more: a. Staphylococcus epidermidis b. Escherichia coli c. Bacillus megaterium d. Pseudomonas putida

a. Staphylococcus epidermidis, Bacillus megaterium

You inoculated an organism into a broth of pH 4. The next day the culture is turbid. Interpret the results. Select one: a. The organism was able to grow at pH 4. b. The organism has a pH range of pH 3 to pH 6. c. The organism survived but could not grow at pH 4.

a. The organism was able to grow at pH 4.

C1 solution of the MoBio/Qiagen DNA extraction kit does which of the following? a. contains SDS which is an anionic detergent that breaks down fatty acids and other lipids b. contains ethanol to wash the DNA c. contains an organic solution to precipitate proteins

a. contains SDS which is an anionic detergent that breaks down fatty acids and other lipids

The purpose of incubating the plates in a jar with a burning candle is to enhance the growth of ______. Select one: a. microaerophiles b. obligate anaerobes c. obligate aerobes d. facultative anaerobes e. facultative aerobes

a. microaerophiles

A lawn of bacteria is placed on the agar surface of a plate and then exposed to UV for 5 minutes. Following incubation, which of the following would you expect? Select one: a. no growth on the plate if the bacteria were UV sensitive b. confluent growth on the plate if the bacteria was UV sensitive c. no growth on the plate if the bacteria were UV resistant d. no growth on the plate if there were endospores present

a. no growth on the plate if the bacteria were UV sensitive

Dinitrogenase reductase is inactivated by a. oxygen b. carbon dioxide c. nitrate d. ammonia

a. oxygen

Darkening of the blood agar is characteristic of a. alpha hemolysis b. beta hemolysis c. gamma hemolysis d. delta hemolysis e. epsilon hemolysis

alpha hemolysis

-Microorganisms are uniquely adapted for survival in different environmental niches. Some bacteria are capable of_________, an energy efficient metabolism in the absence of free oxygen. Anaerobic respiring organisms may utilize SO4 2− (sulfate), CO3 2− (carbonate), or NO3 − (nitrate) as an external electron acceptor following respiratory metabolism. Some soil microorganisms use nitrate in the soil to process hydrogen produced in respiration.________ or ________ is the series of reactions that reduce nitrate to dinitrogen gas. -Some prokaryotes are capable of reducing nitrogen to produce ammonia._______ is part of the natural cycle of nitrogen in the environment, which may result in the depletion of nitrogen from the soil. Crop rotation, composting, and growing leguminous plants with nitrogen-fixing bacteria associated with their roots maintain the balance of nitrogen in the ecosystem. Consult the textbook for detailed information on biochemical cycling of nitrogen in the ecosystem. The ability of microorganisms to reduce nitrate will be examined by inoculating tubes of nitrate broth containing Durham tubes to demonstrate gas production.

anaerobic respiration Denitrification nitrate reduction Denitrification

Which of the following is done to complete the IMViC series of tests? a. Add all the MRVP reagents together to the MRVP broth culture. b. Add methyl red to the citrate slant. c. Add Kovac's to the 1% tryptone broth culture.

c. Add Kovac's to the 1% tryptone broth culture.

What is the pH indicator in Snyder's test agar? Select one: a. phenol red b. bromothymol blue c. bromocresol green d. methyl red

c. bromocresol green

-Catalase is produced by essentially all microorganisms that use oxygen for respiration, such as species of Staphylococcus and Micrococcus. Generally, bacteria that do not utilize oxygen for respiration do not produce catalase, such as species of Streptococcus and Lactococcus. For example, the lactic acid bacteria used in the production of fermented dairy products utilize only fermentative metabolism and do not produce catalase. The ________may be used to distinguish between different genera of bacteria. Organisms that do aerobic respiration produce catalase, while organisms that are strictly fermentative do not produce catalase. The addition of a drop of hydrogen peroxide to a colony will result in the release of oxygen, evident as bubbles in the hydrogen peroxide droplet. -The reagent tetramethyl-p-phenylenediamine dihydrochloride can be used to test an organism's ability to produce cytochrome c oxidase. This oxidase reagent can be added directly to bacteria grown on a plate. Tetramethyl-p-phenylenediamine dihydrochloride serves as an artificial substrate to be oxidized by cytochrome c oxidase in the presence of oxygen (Figure 9-D). Following the addition of the oxidase reagent to the bacteria, the reagent will turn bright blue/purple if cytochrome c oxidase is present. Results must be observed immediately. If exposed to air too long, the oxidase reagent will be oxidized by the air and turn color, leading to false positives (making a culture look oxidase positive when it is really oxidase negative). -Cytochrome oxidases can be found throughout the Bacteria, Archaea, and Eukarya domains. Our understanding of the consequences of lacking a functional cytochrome oxidase comes from the study of dark-dier (dk) mutants of Chlamydomonas reinhardtii with mutations in the mitochondrial gene coding for cytochrome oxidase. C. reinhardtii is a photosynthetic green alga capable of oxy- 115 genic photosynthesis in the light and, if an electron source like acetate is present, aerobic respiration regardless of the presence of light. Therefore, C. reinhardtiirequires a functional cytochrome oxidase for aerobic respiration when grown on acetate in the dark. Sueoka's high salt growth medium plus acetate (HSA) provides acetate to the cells. Minimal growth medium like Sueoka's high salt growth medium (HS), however, lacks an electron source for respiration. HS media contains various salts, phosphates, and trace elements. In order to grow on minimal media, cells must be in the light to do photosynthesis.

catalase assay

Given two unlabeled tubes containing beta-hemolytic bacteria, one of Staphylococcus aureus and the other Streptococcus pyogenes, what is the one test you could perform that would definitively tell the two organisms apart? a. blood agar plate b. catalase test c. milk agar plate d. endospore stain e. oxidase test f. None of the Above

catalase test *catalase tests if it breaks down H2O2 bc thats a reactive species and the one on outside of your body can break it down

Paul Erlich, a German doctor, dreamed about finding a chemical that would cure all diseases. In the late 1800s he began experimenting with _______, which are chemical substances used in living bodies for treatment. In the early 1900s he finally found one chemical that would cure syphilis. This chemical was an arsenicbased compound that would not only cure the disease but kill the patient if too much was taken. In 1928, British physician ________was working with staphylococci in a London hospital. Upon returning to his lab from vacation, he noticed that a plate he had inoculated with staphylococci was contaminated with a mold. He also noticed that the staphylococci had not grown near the mold. Fleming isolated and identified the mold as a species of _________and determined that it produced a substance called penicillin that killed Gram-positive organisms. Fleming had observed_______, which is a symbiotic relationship between two organisms in which there is inhibition, injury or killing of one organism by another. ________kill or inihibit the growth of microorganisms. __________ are lethal to microorganisms. Bacteriocidal agents kill bacteria, virucides destroy viruses, and fungicides kill fungi. ________ are cidal agents that lyse or break open cells. Static agents only inhibit the growth of microorganisms. Bacteriostatic agents inhibit the growth of bacteria and fungistatic agents inhibit the growth of fungi. When a static agent is removed, the microorganism will continue to grow. _________ are antimicrobial agents for use on inanimate surfaces like bench tops. Most disinfectants are too harsh to be applied to living tissue. Ammonia, ethanol, and bleach are examples of widely used disinfectants. You use Vesphene to disinfect the bench tops in lab before and after experiments.

chemotherapeutic agents Alexander Fleming Penicillium antibiosis, Antimicrobial agents Cidal agents Lytic agents Disinfectants

-Among the microbes in the human body, the most common symbiotic relationship is ________. The human gut harbors _________ like members of the genus Bacteroides that require the absence of oxygen to grow. Facultative organisms like _________ can remove the oxygen via ________, allowing the obligate anaerobes an oxygen-free environment to grow. The relationship between Bacteroides species and E. coli is commensalistic. In a commensalistic relationship, one population benefits and one is unaffected. -In the lab, you will observe a commensalistic relationship between __________, which is an obligate anaerobe, and __________, which is a facultative anaerobe. To grow C. sporogenes independently it must be grown in an ________ medium, thioglycollate broth in a sealed flask. __________ is a reducing agent capable of reducing any oxygen present, thereby creating an oxygen-free environment. In lab you will be given nutrient broth, not thioglycollate broth. However, just like in the human gut, by growing S. epidermidis with C. sporogenes, the S. epidermidis will remove the oxygen from the nutrient broth to allow C. sporogenes to grow. -For the billions to trillions of microbial cells in the human body, there are viruses that infect them. Parasitic relationships harm the host or host population while the parasite population benefits. Viruses are __________ whose survival depends upon the host cell because they are only able to multiply within the host cell, at the expense of the host cell. Many bacteriophages (viruses that infect bacteria) are released from their host cell by_________. In Experiment 13: Viruses, you will study more about viruses. Aside from the human body, there are other examples of parasitism. Fleas derive nutrients from the blood of the host while the host is harmed by the loss of blood and nutrients. Bacteria can even parasitize other bacteria. Members of the genus Bdellovibrio are parasitic to E. coli, invading and multiplying within the E. coli cell.

commensalism obligate anaerobes Escherichia coli aerobic respiration Clostridium sporogenes Staphylococcus epidermidis oxygen-free Thioglycollate obligate intracellular parasites lysing open the host cell, killing it

A series of pH tubes (pH 3 - pH 12) are inoculated with the same organism. Growth appears in pH 3, 4, 5, 6, and 7 with the most growth appearing at pH 4. How would this microorganism be characterized, what is its optimum pH and pH range. Select one: a. Acidophile; pH 4; pH 3 - pH 5 b. Alkalinophile; pH 4; pH 3 - pH 7 c. Alkalinophile; pH 5; pH 3 - pH 7 d. Acidophile; pH 4; pH 3 - pH 7 e. Alkalinophile; pH 4; pH 3 - pH 5

d. Acidophile; pH 4; pH 3 - pH 7

The phenol red broths used to test for fermentation contain which carbohydrates? Select one: a. Galactose, lactose, sucrolose, maltose b. Maltose, mannitol, glucose, lactose c. Fructose, maltose, lactose, sucrose d. Glucose, lactose, sucrose, mannitol

d. Glucose, lactose, sucrose, mannitol

As the number of cells in a broth increases, there is a decrease in the turbidity of the solution. Select one: a. True b. False

false

For experiment 7A, you will inoculate five tubes of nutrient broth with 100microliters of the same organism then place all the tubes at the same temperature. Select one: True False

false

Neither Staphylococcus nor Pseudomonas were sensitive to ethanol. Select one: True False

false

Nitrate respiration is a special type of fermentation. Select one: True False

false

Osmosis describes the flow of water from areas of more solute to areas of less solute. Select one: a. False b. True

false

Deinococcus radiodurans survives high temperatures because it can quickly repair its DNA. Select one: True False

false **temp messes up protein not DNA. It survives lots of UV

-A plate method employs gelatin added to a nutrient medium. Agar is present in this medium, so liquefaction cannot be used to indicate _________(EC 3.4.24.24) production. The addition of acid to the plate will result in precipitation of the gelatin proteins, making the agar look white within a few minutes of adding the HCl.An organism which produced gelatinase will have a clear, transparent area around it due to the hydrolysis of gelatin. -There are twenty amino acids commonly found in living cells. All of them have two important functional groups, a _______ group and an _______ group, attached to the alpha carbon. Different side chains or "R" groups, also attached to the alpha carbon, distinguish the different amino acids. -Two amino acids, cysteine and methionine, also contain sulfur atoms. Cysteine contains a sulfhydryl group (—SH) that plays an essential role in protein structure by connecting amino acid chains through disulfide linkages (R—S—S—R). Some microorganisms utilize the sulfur-containing amino acids as a source of energy for the cell. Cleavage of the sulfhydryl group is the first step of metabolic breakdown. This reaction (shown in the figure below) is catalyzed by the enzyme ________ (EC 4.4.1.15), a carbon-sulfur lyase, and results in the release of hydrogen sulfide gas (H2S), which is responsible for the rotten egg odor (Figure 9-H).

gelatinase carboxylic acid (—COOH) amino (—NH2) cysteine desulfhydrase

EMB agar contains the differential component _______

lactose

-Staphylococci are able to grow in media or materials with a fairly high concentration of salt, which partially explains its role in food poisoning. The medium ________ was developed for isolating staphylococci from food samples. This medium contains 7.5% NaCl, an elevated concentration that inhibits the growth of many microorganisms and makes it selective for those that tolerate this concentration of salt. MSA is also a differential medium by containing the fermentable carbohydrate mannitol. The pH indicator ________ in MSA allows a drop in pH to be seen rather than measured. At a neutral pH, phenol red has an orange/red color. If the pH drops, as happens when mannitol is fermented and acids are produced, phenol red turns _______. At an alkaline pH, phenol red becomes _______. -Any organism that can grow on MSA can tolerate 7.5% salt. Colonies of mannitol fermenting organisms and the medium around them will be yellow, while colonies of organisms that do not ferment mannitol are pale or white on pink medium. S. aureus and S. saprophyticus ferment mannitol while S. epidermidis does not. While there are many other organisms that grow with 7.5% salt and even ferment mannitol, they are not likely to be found in the same environment with staphylococci. -Microbiologists look for the production of coagulase to confirm the identity of a suspected isolate as S. aureus by inoculating a small tube of plasma. __________ is the liquid portion of anticoagulated blood and contains the clotting factors. One clotting factor is ________, which is present in plasma as a soluble protein. Coagulase causes fibrinogen to break into short strands of fibrin, which interact to form a fibrin clot. Coagulase production is evident when a fibrin clot forms in the tube of inoculated plasma. Symbiosis is the close and long-term biological relationship between two different organisms. Humans are colonized by as many as 1000 species of bacteria. For the most part, the relationship between humans and their bacterial symbionts is mutualistic, where both populations benefit from the association. Another example of mutualism is the lichen, which is formed by a heterotrophic fungus and a photosynthetic alga or cyanobacterium. The lichen can exist in areas where neither the fungus nor the alga could exist alone, with the alga producing organic matter from CO2 and some nutrients to be used by the fungus, while the fungus protects the alga from high light intensities and provides water and minerals to the alga. Yet another example of mutualism is found in the rumen of cattle which provides microorganisms with a steady food supply and a stable environment where microorganisms produce cellulase enzymes to degrade plants fibers ingested by cattle.

mannitol salt agar (MSA) phenol red bright lemon yellow fuchsia pink Plasma fibrinogen

Clinical microbiologists and physicians must be aware of the _______ of different antimicrobial chemotherapeutic agents. The mode of action is the way the agent kills or inhibits growth. Penicillin prevents the insertion of new peptidoglycan into an expanding cell wall, weakening the cell wall and making the cell susceptible to osmotic lysis. Because Gram-positive cells have lots of peptidoglycan in their cell wall they are vulnerable to damage by penicillin. _______is an aminoglycoside that prevents protein synthesis by binding to the 16S rRNA in the small 30S subunit of the bacterial ribosome, interfering with the binding of formyl-methionyl tRNA to the 30S subunit. All bacteria make their own proteins, but streptomycin is only effective against bacteria that don't have a resistance mechanism against the antibiotic.

mode of action Streptomycin

Carbohydrates are compounds composed of carbon, hydrogen, and oxygen in a 1:2:1 ratio. The formula (CH2O)n indicates that there are twice as many hydrogen atoms as carbon and oxygen atoms. Small carbohydrates are ___________, which are single sugars, usually with five (e.g., ribose) or six (e.g., glucose) carbons. ________, which means "few sugars," are composed of two or more monosaccharides. Polysaccharides are larger polymers of monosaccharides and may serve as structural components (e.g., cellulose, chitin) or as important reserve carbon and energy sources (e.g., cellulose, dextran, glycogen, or starch). Enzymes that degrade these polymers have specifice substrates (Figure 9-G). Glycogen, a branched polymer of glucose with α (1→4) and α (1→6) ________, is the reserve energy polysaccharide of animal cells, including human cells. Microorganisms produce dextran, another polymer of glucose. Cellulose is a polymer of glucose residues linked with β (1→4) glycosidic bonds. Cellulose is a structural component of plant cell walls. You'll learn more about cellulose in Experiment 12. Starch is a polymer of glucose connected by α (1→4) glycosidic bonds. Starch is produced by plants, serving as a reserve food supply. Some microorganisms produce an extracellular enzyme, called ________ (EC 3.2.1.1), that can break the glycosidic bonds between the glucose subunits in starch. Amylase hydrolyses starch into the smaller subunits that can then be transported into the bacterial cell to provide energy or cellular components. Starch can be dissolved into a liquid growth medium into which agar is added. The medium is sterilized and poured into Petri dishes, where it solidifies and looks much like nutrient agar. The addition of iodine to the plated medium makes starch evident because the iodine reacts with the starch to produce a brown color. If a plate is inoculated with bacteria and incubated to allow for microbial growth, amylase production by a microorganism can be determined. A clear area or ________ will be evident around an amylase-producing colony after the plate is flooded with iodine.

monosaccharides Oligosaccharides glycosidic bonds amylase zone of hydrolysis

-Another way to determine whether a cell has flagella is by using_______which is used to determine whether microorganisms possess ______ and thus are capable of motility. This medium contains a low agar concentration (0.4%) to allow movement of motile bacteria. Due to the low agar concentration, motility test medium should be kept in refrigerator until immediately before it is inoculated. The medium also contains a ________ to make interpretation of results easier. TTC is used by the bacteria as an electron acceptor. In its oxidized form, TTC is colorless and soluble; when it is reduced, it is red and insoluble. If the bacteria are motile, then the red color will radiate in all directions away from the original stab line. The entire deep may even turn red. If the bacteria are not motile then you will see a red line only where you stabbed the deep. Larger motile microorganisms like the eukaryotic green alga Chlamydomonas reinhardtii can be seen in wet mounts using brightfield, phase contrast or darkfield light microscopy. Using the _______ a cell suspension can be suspended from a coverslip over a depression slide to allow freedom of movement for the algal cells. Motile cells in the suspension will move in a directed fashion, darting from place to place trying to find nutrients and light (algae are photosynthetic). This movement is distinguishable from______ the random movement of particles suspended in a fluid.

motility test medium flagella tetrazolium salt (TTC) hanging drop method, Brownian motion,

Nitrate broth contains _____________ which the bacteria can ____________. Select one: a. lipids; store as excess carbon b. sugar; ferment c. nitrogen; oxidize d. protein; breakdown with proteases e. nitrate; reduce

nitrate; reduce

-The bacterium stimulates certain root cells to divide repeatedly, forming a nodule. When the plant dies, the nodule disintegrates and some dormant bacterial cells survive and reproduce in the soil, where they can infect other legume plants. -The bacteria are able to fix nitrogen only when in this mutualistic symbiotic relationship. The plant benefits by acquiring fixed nitrogen, and in return supplies the bacterium with photosynthesis products which it can oxidize to generate energy. The infection process results in the synthesis of several proteins, some encoded by the DNA of the plant and others by the DNA of the bacterium. One example is leghemoglobin, an iron-containing heme similar to the hemoglobin found in animals. It binds oxygen within the nodule, regulating the oxygen concentration so that it is high enough for the aerobic bacteria to live, but not so high that the enzyme ________, which carries out nitrogen fixation and is oxygen sensitive, is inactivated. Leghemoglobin also gives the nodules their pink color. -Rhizobium trifolii lives in symbiosis with white clover. The nitrogen-fixing bacteria penetrate the roots of the plant and form a nodule, where they live and fix atmospheric nitrogen, providing a nitrogen source for the plant. -This nitrogen contribution is especially valuable for plants growing in soils deficient in nitrogen. The effectiveness of this plant-bacterial symbiosis in restoring soil fertility is the basis for the principle of crop rotation, in which a leguminous crop is substituted for the main cash crop in a field after a certain number of growing seasons. This farming technique has been practiced for hundreds of years and is an alternative to the addition of artificial nitrogen fertilizers. Rhizobium is involved in nodule formation in plants living in the temperate zone including Louisiana. Members of this genus are ________

nitrogenase Gram-negative aerobic rods.

________ describes the acidity or alkalinity of a solution. pH is defined as the log [H+] and is expressed on a logarithmic scale from 0 to 14, with pH 7 as neutrality, meaning that a solution has equal concentrations of H+ and OH− ions. pH greatly affects the growth of microorganisms. Every microorganism has an _______ pH at which it grows best, but can grow a bit above or below the optimum pH as well. The pH units within which an organism can grow is its ______. The maximum rate of enzyme activity occurs at the organism's optimum pH. Alterations in the three-dimensional structure of microbial proteins can occur when the organism experiences pH conditions outside of its range; extreme deviation results in denaturation of proteins. Microorganisms are adapted to survive at almost every pH. _________ grow at pH values below 6. Members of the genus Lactobacillus produce the acid responsible for the relatively low pH (~4.5) of the adult human vagina. Propionibacterium acnes, associated with the development of acne, is part of the normal microbiota of the skin, which has a pH of near 4. Yeasts and molds tolerate low pH better than most bacteria; hence, yeast and mold frequently decompose fruit. Sabouraud's Agar growth medium, with a pH of 5.6, is selective for these organisms. Many microorganisms, including E. coli and Vibrio cholerae, prefer pH close to 7 and are called _______. Organisms called _______ or ________ prefer pH above 7, such as Agrobacterium species that infect plants, which grow in soils with a pH of 12. Some organisms are acid tolerant and others are alkaline tolerant, meaning they prefer and grow best near neutral pH but can tolerate and grow in an acidic or alkaline environment.

pH optimum pH range Acidophiles neutrophiles basophiles alkalinophiles

experiment 7 Pasteur discovered that grape juice could be sterilized by heating, leading to the development of ________, in which gentle heating (71.5-74°C or 160-165°F for 15-30 seconds) was used to eliminate organisms that cause spoilage in a food product such as beer or wine. The effect that temperature has upon an organism depends upon the specific microbe. Rice is easily contaminated with species of _______ because of how it is grown and can become contaminated with toxins produced by Bacillus species, even though rice is prepared using boiling water. The genus Bacillus contains many species that produce endospores, and while vegetative cells are killed by boiling water, the endospores may survive and later germinate in rice that is held at room temperature.

pasteurization Bacillus

The ability to ferment a carbohydrate can be determined if a single carbohydrate is added to a nutrient broth containing non-fermentable nutrients to support growth and a pH indicator. The carbohydrate broths used in this lab contain _______ as a pH indicator. Around _______ pH from 6.8-8.2, the broths have an orange-red appearance. Microbial fermentation products such as alcohols help maintain neutral pH in the growth medium. If acid production causes the pH to drop below 6.8, the phenol red becomes bright yellow. Various acids such as lactic acid, succinic acid and formic acid as well as carbon dioxide can lower the pH of the growth medium. Above pH 8.2, phenol red turns bright pink. Alkaline products such as those made from the degradation of peptone can increase pH of the growth medium. A _______, which is a small inverted glass vial, is present in the tube of broth to trap gases produced in fermentation. Gases are evident as a bubble in the Durham assembly, although sometimes so much gas is produced that the entire Durham tube is filled causing the tube to float in the broth.

phenol red neutral Durham tube

-Glycogen, a branched polymer of glucose with α (1→4) and α (1→6) glycosidic bonds, is the reserve energy polysaccharide of animal cells, including human cells. Microorganisms produce dextran, another polymer of glucose. Cellulose is a polymer of glucose residues linked with β (1→4) glycosidic bonds. Cellulose is a structural component of __________. Starch is a polymer of glucose connected by α (1→4) glycosidic bonds. Starch is produced by plants, serving as a reserve food supply. Some microorganisms produce an extracellular enzyme, called ________ (EC 3.2.1.1), that can break the glycosidic bonds between the glucose subunits in starch. Amylase hydrolyses starch into the smaller subunits that can then be transported into the bacterial cell to provide energy or cellular components. Starch can be dissolved into a liquid growth medium into which agar is added. The medium is sterilized and poured into Petri dishes, where it solidifies and looks much like nutrient agar. The addition of iodine to the plated medium makes starch evident because the iodine reacts with the starch to produce a brown color. If a plate is inoculated with bacteria and incubated to allow for microbial growth, amylase production by a microorganism can be determined. A clear area or _______ will be evident around an _______ colony after the plate is flooded with iodine.

plant cell walls amylase zone of hydrolysis amylase-producing

-Carbohydrates are compounds composed of carbon, hydrogen, and oxygen in a 1:2:1 ratio. The formula (CH2O)n indicates that there are twice as many hydrogen atoms as carbon and oxygen atoms. Small carbohydrates are monosaccharides, which are ________, usually with five (e.g., ribose) or six (e.g., glucose) carbons. -_________, which means "few sugars," are composed of two or more monosaccharides. _________ are larger polymers of monosaccharides and may serve as structural components (e.g., cellulose, chitin) or as important reserve carbon and energy sources (e.g., cellulose, dextran, glycogen, or starch). Enzymes that degrade these polymers have specifice substrates

single sugars Oligosaccharides Polysaccharides

When cytochrome c oxidase reduces oxygen, byproducts such as the ________ (O2 −), _______ (H2O2), and _______ (OH•) are produced (Figure 9-B). These byproducts are toxic to cells and aerobic organisms (obligate aerobes, facultative aerobes and microaerophiles) have enzymes to detoxify the byproducts. The enzyme _______breaks hydrogen peroxide into water and molecular oxygen (Figure 9-C). The oxygen produced can be observed due to the production of bubbles.

superoxide anion hydrogen peroxide hydroxyl radicals catalase

A UV sensitive organism will not be able to survive exposure to ultraviolet radiation for a lengthy period of time. Select one: True False

true

An autotroph is an organism that obtains carbon from the carbon dioxide in the air. Select one: a. True b. False

true