BIOL 3339 Chapter 7

The group of microbes adapted for growth in extremely salty environments is termed

halophiles

Microbes that grow at temperatures between 85 and 113°C are called

hyperthermophile

Microbes that grow at temperatures above 85°C are called ______. mesophiles psychrophiles psychrotrophs hyperthermophiles

hyperthermophiles

Microbes that are damaged by atmospheric levels of oxygen but still require oxygen are called

microaerophiles

Microbes that are damaged by atmospheric levels of oxygen but still require oxygen are called _______. microaerophiles facultative anaerobes aerobes aerotolerant anaerobes

microaerophiles

At high temperatures, membrane lipids tend to become _________ fluid, while at low temperatures membrane lipids tend to become _________ fluid.

more/less

Microbes that can not grow in the presence of oxygen are called _______. obligate anaerobes facultative anaerobes aerotolerant anaerobes aerobes

obligate anaerobes

Environments that are low in nutrients are ______. oligotrophic eutrophic heterotrophic piezophilic

ogliotrophic

Crescentin, the shape-determining protein of vibrioid cells, localizes to _____. the nucleoid both cell poles one side of the cell the outer membrane

one side of the cell

MinCDE proteins _____. are located at midcell by the Z ring form at midcell, then split and move to the poles oscillate between the cell poles are attached to the peptidoglycan at cell poles

oscillate between the cell poles

Which two of the following proteins are components of the E. coli divisome?

FtsZ FtsA

Microbes that naturally live free-floating in aquatic environments are ______. growth arrested interfacial planktonic sessile

planktonic

Among enumeration techniques, those involving _____ have limitations regarding the ability of many organisms present in the environment to grow under the conditions provided. batch cultures selective media microscopy plating

plating

The only cells that can be counted on agar plates are those that are ______. pure viable aerobic planktonic

viable

Adding salt or sugar helps to prevent microbial growth in food because these affect the ______ of the food. water activity nutrient density boiling point

water activity

Microbial colonies separated from each other on agar plates are each assumed to arise from _______. persisters a population of microbes visible cluster of organisms a single cell

a single cell

Slime on rocks in a lake and infected areas of hip implants are places where we expect to find microbes growing as

biofilms

Microbes that grow equally well with or without oxygen are called _________ anaerobes.

aerotolerant

Which of the following are effects of ionizing radiation on cells? breaks hydrogen bonds solubilizes membranes protein oxidation hydrolyzes peptidoglycan hydrolyzes ATP

breaks hydrogen bonds protein oxidation

Which of these is not a typical mechanism for starvation proteins? Renaturing proteins Synthesis of additional ribosomes Protecting DNA Strengthening the cell wall

Synthesis of additional ribosomes

Which two of the following responses to growth at low temperature have been identified in microbes? Alter the G + C content of stable RNAs Synthesize an ATPase that pumps protons out of the cell Synthesize compatible solutes to decrease the freezing point of cytosol Increase the levels of unsaturated fatty acids in membranes

Synthesize compatible solutes to decrease the freezing point of cytosol Increase the levels of unsaturated fatty acids in membranes

While using a spectrophotometer to enumerate a culture, you obtain a value of 0.95. How should an accurate absorbance value be determined? The spectrophotometer should be blanked with the sample, and then repeated. The sample should be diluted and the dilution used for the reading. The sample should be discarded and the process repeated with a new sample. The value of 0.95 is sufficiently accurate and should be recorded.

The sample should be diluted and the dilution used for the reading.

ppGpp is a signaling molecule, related to _____, that regulates the cell's response to stressors so the cell can survive. peptidoglycan strands toxin-antitoxin modules membrane transport proteins DNA and RNA nucleotides

DNA and RNA nucleotides

True or false: Numerous proteins found in biofilm cells are not observed when the same cells are planktonic.

True

True or false: Co-culture of a microbe of interest with plant tissue is often successful in the laboratory cultivation of some plant pathogens.

True; Some microbial species require the presence of another organism to survive, including plants.

Which two ingredients, when present, would render a bacterial medium complex? Potassium phosphate Tryptic soy broth Ammonium sulfate Yeast extract

Tryptic soy broth Yeast extract

Autoinducers important for quorum sensing include oligopeptides extracellular polymeric substances flavonoids N-acylhomoserine lactones

N-acylhomoserine lactones

Which enumeration technique uses numerous replicates of several dilutions of a culture to estimate cell numbers? Flow cytometry Plate counts Most probable number Coulter counting

Most probable number

Which technique is not suitable for determination of population size through the measurement of cell mass? Total protein concentration Most probable number analysis Dry weight measurements

Most probable number analysis

Which two of the following statements are evidence in support of the importance of MreB in determining cell shape in rod-shaped bacteria? MreB proteins polymerize to form filaments that act at the plasma membrane. Rod-shaped cells in which MreB has been depleted assume a spherical shape. MreB proteins interact directly with the FtsZ ring at midcell. Coccoid-shaped cells lack proteins in the MreB family.

Rod-shaped cells in which MreB has been depleted assume a spherical shape. Coccoid-shaped cells lack proteins in the MreB family.

Yeast extract, an aqueous extract of brewer's yeast, is often used in complex media where it provides _____. [Choose three.] carbon sources iron compounds nitrogen compounds D vitamins B vitamins

carbon sources nitrogen compounds B vitamins

The minimum, maximum, and optimum temperatures for growth are the ____________ temperatures.

cardinal

The number of microbes in a sample as determined by viable plate counts is expressed as ______. colony forming units hemocytometers direct cell counts most probable number

colony forming units

Vibrioid, or comma-shaped cells, have their shape determined by a protein termed _____. FtsZ crescentin elastin MreB

crescentin

A solid or liquid preparation used to grow, transport, and store microorganisms is termed a(n) ______. chemostat biofilm enrichment culture culture medium

culture medium

One response to nutrient limitation is for the affected cell to form an endospore. Other microbes become dormant by forming _____. thicker membranes biofilms ectospores cysts

cysts

The part of the microbial growth curve when cell density decreases is called the _______ phase.

death

The part of the microbial growth curve when cell density decreases is called the ______. stationary phase lag phase exponential phase death phase

death phase

Culture media that contain only ingredients of known chemical composition are referred to as ______. defined enriched differential complex

defined

Which cellular effect is not typical of high temperatures? Denature proteins Degrade mRNA Disrupt membrane transporters Disrupt lipid membranes

degrade mRNA

Cells that have become part of developing biofilm can leave the surface through ______. exopolymer production diffusive transport replication and growth desorption and sloughing

desorption and sloughing

Media used to distinguish among groups of microbes based on their reaction to the media are called ______. selective media differential media supportive media enriched media

differential media

The purpose of performing the streak plate technique is to _____. assess the essential nutrients required by most bacteria in the original sample repetitively sample a culture to estimate the viable count successively sterilize samples of a culture to enumerate the number of microbes present dilute a culture on the surface of a medium so that single colonies form

dilute a culture on the surface of a medium so that single colonies form

Flow cytometry, microscopy, and Coulter counting are all forms of_______counting of cells in a microbial culture.

direct

Petroff-Hauser slides are used for ______ counting of cells in a microbial culture.

direct

When the number of cells in a culture is determined by microscopic observation, this is a type of ______. viable counting indirect counting direct counting specific counting

direct counting

In the example of interdomain communication between Rhizobium species and leguminous plants, the advantage of the successful interaction for the microbe is _____. secretion of amino acids from the plant energy assistance from the plant constant temperature from the plant nutrient production from the plant

energy assistance from the plant

General purpose media fortified with blood to encourage the growth of fastidious microbes are called _______. supportive media differential media enriched media selective media

enriched media

To increase the number of microbes with specific metabolic activities in a culture microbiologists use a technique known as _________ culture.

enrichment

Environments that are rich in nutrients are ______. piezophilic oligotrophic eutrophic heterotrophic

eutrophic

The part of the microbial growth curve when cells are growing and dividing at their maximal rate is called the ________ phase.

exponential

The part of the microbial growth curve when cells are growing and dividing at their maximal rate is called the ______. death phase exponential phase lag phase stationary phase

exponential phase

he sticky polymers that form in biofilms are collectively called ______. peptidoglycan N-acylhomoserine lactones secreted proteases extracellular polymeric substances

extracellular polymeric substances

Microbes that do not require oxygen but grow better in its presence are called _______. facultative anaerobes aerobes microaerophiles aerotolerant anaerobes

facultative anaerobes

The use of laser light scattering to count cells is called

flow cytometry

One response to nutrient limitation is for the affected cell to _____. synthesize a flagellum increase in size initiate chromosome replication form an endospore

form an endospore

The effect of ionizing radiation on Deinococcus radiodurans is to _____. fragment the chromosome hydrolyze peptidoglycan oxidize disulfide bonds in enzymes produce holes in the membrane

fragment the chromosome

Growth of microbes on blood agar permits the distinction of _____. lactose fermenting and nonfermenting bacteria hemolytic and nonhemolytic bacteria motile and immotile bacteria aerobes and anaerobes

hemolytic and nonhemolytic bacteria

Which two of the following are advantages to microbes living in a biofilm? increased opportunity for gene transfer protection from UV light less competition for available nutrients increased susceptibility to antibiotics

increased opportunity for gene transfer protection from UV light

A liquid preparation used to supply energy and nutrients to microorganisms in the laboratory is called a culture ______. milieu environment solution medium

medium

Many psychrophiles begin to leak cellular constituents at temperatures higher than 20°C because of _____. cytosol expansion membrane disruption dissolution of peptidoglycan synthesis of cold shock proteins

membrane disruption

The method for separating cells by dragging samples over different sectors of a plate using a microbial loop is called ________ plating.

streak

After an extended time in growth arrest, some cells are temporarily unable to grow, at least under the laboratory conditions used to culture them. These cells are best described as ______. dead viable but not culturable persisters metabolically inactive

viable but not culturable

eef extract is an aqueous extract of lean beef and contains _____. [Choose two.] vitamins lipids phosphorus amino acids agar

vitamins amino acids

The primary challenge to providing sufficient oxygen to aerobes grown in laboratory culture is that _____. oxygen is poorly soluble in liquids oxygen represents only about 20% of air oxygen is flammable and a significant hazard in the lab oxygen is supplied from the water (H2O) used for culturing microbes

oxygen is poorly soluble in liquids

A phenomenon documented by microbial ecologists, that the number of cells in an environment observed by microscopy is often much higher than the population size determined by plating is referred to as "the great ______________.

plate count anomaly

Which two of the following strategies are used by microbes to limit the potentially damaging effects of osmosis in hypotonic environments? presence of a peptidoglycan-containing cell wall presence of mechanosensitive channels in the plasma membrane synthesize transporters to regulate the flow of ions across the membrane synthesize or import compatible solutes

presence of a peptidoglycan-containing cell wall presence of mechanosensitive channels in the plasma membrane

Peptones, a source of carbon, energy, and nitrogen in complex media, are derived from _____. seaweed carbohydrates protein sources sheep blood

protein sources

Using molecular signals to communicate microbial density is referred to as ___________ sensing.

quorum

The exchange of signaling molecules to coordinate gene expression between members of a bacterial population is called ____. feedback sensing gene regulation quorum sensing paracrine signaling

quorum sensing

Using molecular signals to communicate microbial density is referred to as ______. chemotaxis biofilm formation binary fission quorum sensing

quorum sensing

is a process by which a population of bacteria can coordinate gene expression through the exchange of signaling molecules.

quorum sensing

In the example of interdomain communication between Rhizobium species and leguminous plants, the advantage of the successful interaction for the plant is _____. energy production by the Rhizobium secretion of antibiotics by the Rhizobium secretion of amino acids by the Rhizobium secretion of ATP by the Rhizobium

secretion of amino acids by the Rhizobium

Media that allow the growth of some microbes but not others are called __________ media.

selective

When a microbial culture is diluted several times before plating to count the number of cells in the original sample, the technique of ______ dilution is used.

serial

Microbes that naturally live attached to surfaces in aquatic environments are ______. interfacial planktonic rare sessile

sessile

For bacteria growing in batch culture conditions, the long-term stationary phase may last up to _____. several years several weeks several hours

several years

Persister cell formation is believed to be triggered by _____. [Choose two.] starvation chaperone proteins ppGpp production reactive oxygen species

starvation ppGpp production

The part of the microbial growth curve when cells reach their maximum density is called the _________ phase.

stationary

The part of the microbial growth curve when cells reach their maximum density is called the ______. death phase stationary phase lag phase exponential phase

stationary phase

Cells are counted by measuring electrical resistance as they pass through a small pore using the _____. flow cytometer thermocycler Coulter counter Petroff-Hauser counting chamber

Coulter counter

Which differential medium is used to determine an organism's growth response to varying concentrations of oxygen? thioglycollate chocolate agar blood agar MacConkey

thioglycollate

True or false: Almost all rod-shaped bacteria synthesize at least one MreB homologue.

true

Which three of the following ingredients could be used to make defined culture media? Glucose Tryptone Yeast extract Ammonium sulfate Potassium phosphate

Glucose Ammonium sulfate Potassium phosphate

Which of these is not a use of culture medium? Growing microbes Reviving dead cultures Transporting organisms Storing microbial isolates

Reviving dead cultures

A suspension of cells is distributed over the surface of a plate with a sterile bent rod in ______ plating.

spread

A pure culture is also referred to as a(n) ________ culture.

axenic

Microbes that grow best at temperatures of 15°C are called

psychrophiles

Since it is not possible to tell whether a microbial colony arose from a single cell, the term ______________ units is used.

colony forming

Increasing the size of peptidoglycan during cell division is a challenge because _____.

its strength must be maintained when new subunits are added

The colonies that develop on blood agar differential medium can be classified according to their ability to _____.

lyse blood cells

At which of the following water activities are most microbes likely to grow? 0.50 0.10 0.90 0.99

0.99

Which of the following statements regarding mature biofilms is false? DNA present in the biofilm matrix may be a source of genetic transfer. Cells communicate with one another by quorum sensing molecules. A mature biofilm is a homogeneous community of microorganisms. A mature biofilm includes a fraction of the cells in the persister state.

A mature biofilm is a homogeneous community of microorganisms.

Which two of the following statements describe evidence about the origin of persister cells in a population? A small subset of individuals in a population spontaneously become persisters. Starvation triggers the formation of persister cells in a population. Induction of antibiotic resistance genes triggers persister formation. Quorum sensing is necesssary for the formation of persisters.

A small subset of individuals in a population spontaneously become persisters. Starvation triggers the formation of persister cells in a population.

Which of these is not a good reason to use agar as a solidifying agent for culture media? Gels at a temperature that microbes can tolerate Acts as a microbial nutrient Useful over a wide range of temperatures Melts at 90°C but solidifies at 45°C

Acts as a microbial nutrient

Which technique is used to increase the number of microbes with specific metabolic activities in a culture? Axenic culture Enrichment culture Spread culture Pure culture

Enrichment culture

Which two of the following techniques aid in the removal of oxygen from media used to culture anaerobes? Add reducing agents like thioglycollate Include an antibiotic to inhibit growth of aerobic contaminants Use double-distilled and deionized water Boil the medium to drive off any oxygen present

Add reducing agents like thioglycollate Boil the medium to drive off any oxygen present

Which characteristic of cells cannot be detected using flow cytometry? Internal complexity Size Antibiotic resistance Antibody binding

Antibiotic resistance

Which growth temperature is not considered one of the three cardinal temperatures? Minimum Average Optimum Maximum

Average

Oxygen is provided to organisms grown in laboratory culture by which two of the following methods? Bubbling O2 gas through the medium Including a catalyst to convert H2O to O2 Shaking flasks to provide aeration Eliminating reducing agents from media

Bubbling O2 gas through the medium Shaking flasks to provide aeration

hich two of the following are limitations to the use of plating techniques for enumeration? Microbial cells in a population occupy a continuum of cell sizes, giving inaccurate counts. Cells in complex arrangements will produce a single colony, resulting in low counts. Supportive media are also good media for contaminants, resulting in high counts. Warm agar used in the pour plate technique may kill some cells.

Cells in complex arrangements will produce a single colony, resulting in low counts. Warm agar used in the pour plate technique may kill some cells.

Which two of the following are tolerant of high doses of ionizing radiation?

Clostridium endospores Deinococcus radiodurans

Excessive exposure to UV light typically kills cells by damaging ______. porphyrins DNA proteins lipids

DNA

Excessive exposure to UV rays (i.e., radiation) can kill microbes by overwhelming the cell's ability to repair its ___.

DNA

Which two of the following conditions lead to a cell experiencing growth arrest? Shifting from one carbon source to another Decrease in temperature to its minimum Metabolizing all available nitrogen Chemotaxis towards a new carbon source Infection by a temperate bacteriophage

Decrease in temperature to its minimum Metabolizing all available nitrogen

Which two of the following describe important limitations to the use of enrichment cultures? Enrichment cultures yield the organism that grows the fastest. Enrichment cultures can only be used to reflect soil populations. Enrichment cultures often become anaerobic, limiting their use to isolating anaerobes. Enrichment cultures are not representative of the population sampled.

Enrichment cultures yield the organism that grows the fastest. Enrichment cultures are not representative of the population sampled.

Which of the following statements regarding mature biofilms is false? Extracellular polymeric substances include plastics and corroded metal pipes. Some microbes obtain their energy source from the waste of another microbe. The heterogeneous environment in a mature biofilm results in cells with different growth rates. A mature biofilm exhibits a gradient of nutrients, with the inside of the biofilm depleted.

Extracellular polymeric substances include plastics and corroded metal pipes.

True or false: Enrichment cultures are pure cultures.

False; Enrichment cultures usually contain more than a single species, each having similar characteristics.

Which of the following statements about obligate anaerobes is correct? They are exclusively found in the Archaea. They are never found in oxic environments. They maintain high concentrations of catalase enzyme. In oxic environments, they associate with facultative anaerobes.

In oxic environments, they associate with facultative anaerobes.

Which two of the following statements regarding new approaches to culturing microbes are correct? Marine microbes often grow better in culture when higher salt concentrations are used. In situ cultivation using dilute samples in an enclosure permits axenic cultures to form. Inclusion of mammalian blood is critical for the growth of most pathogens. Co-culture of two organisms is often more successful than culturing them separately. Only pure cultures are valid for the study of bacterial pathogens.

In situ cultivation using dilute samples in an enclosure permits axenic cultures to form. Co-culture of two organisms is often more successful than culturing them separately.

Where does peptidoglycan synthesis start in bacteria? In the periplasmic space In the cell wall Outside of the cell wall In the cytoplasm

In the cytoplasm

How does thioglycollate medium allow the distinction of organisms with different responses to oxygen? Bubbling oxygen through the medium promotes growth of aerobes over anaerobes. Incubation in an anaerobic chamber promotes growth of anaerobes over aerobes. Application of peroxide drops illustrates the presence of catalase by bubbling. Inclusion of a reducing agent in the medium results in a gradient of oxygen.

Inclusion of a reducing agent in the medium results in a gradient of oxygen.

Which of the following best describes the movement of AHL (N-acylhomoserine lactone) across the plasma membrane of a bacterial cell? It requires active transport. It is freely diffusible. It requires facilitated diffusion. It requires the proton motive force.

It is freely diffusible.

The Z ring is inhibited from forming at any location other than at midcell by the movement of the _____ proteins.

MinCDE

Which class of microbes are adapted for growth in extremely hypertonic environments? Protists Wall-less microbes Osmophiles Vibrioids

Osmophiles

A method for separating cells by inoculating molten agar with the cells and then adding the agar to a sterile petri dish is ______ plating.

Pour

The RNA polymerase subunit that directs the ribosome to synthesis proteins helpful for survival during starvation is ______. RpoS RNApol III RpoQ RNApol I

RpoS

Which technique can be used to enumerate the cells in a liquid culture? Enrichment Serial dilution Streak plating Pure culturing

Serial dilution

"Dilution on a surface" best describes which technique? Pour plate Spread plate Enrichment Streak plate

Streak plate; The streak plate process will dilute bacteria after each additional set of streaks. However, the pour plate and spread plate processes maintain the same number of bacteria throughout.

Laboratory culture techniques like the use of a GasPak or anaerobic chamber are important for which of the following reasons? These technique purify gases to reduce contamination from the atmosphere. These techniques eliminate the presence of oxygen for the culture of anaerobes. These techniques raise the concentration of carbon dioxide for the culture of autotrophs. These techniques promote laboratory safety by eliminating flammable gases from the lab.

These techniques eliminate the presence of oxygen for the culture of anaerobes.

After an extended time in growth arrest, some cells are temporarily unable to grow, at least under the laboratory conditions used to culture them. These cells are said to be in a state known by the abbreviation __________.

VBNC; viable but not culturable

Psychrotrophs differ from psychrophiles in that psychrotrophs have _____. no temperature optimum a much higher maximum temperature abundant antifreeze proteins in their cytoplasm a much lower maximum temperature

a much higher maximum temperature

Turbidity of a culture is typically measured by _______. cell mass absorbance Coulter counting plate counts

absorbance

The most commonly used solidifying agent for supportive medium is

agar

Direct counting of cell numbers can be done with all of the following tools except _______. Petroff-Hauser slides counting chambers agar plates

agar plates

Microbes that grow best at pH values above 8 are termed

alkaliphiles

To be effective, a culture medium must contain _____. antibiotics to inhibit growth of undesirable microbes all nutrients required for growth a pH indicator oxygen

all nutrients required for growth

Strict anaerobes may employ which two of the following metabolic strategies? anaerobic respiration aerobic respiration photosynthesis fermentation

anaerobic respiration fermentation

Cells in a growth arrested state _____. are dead actively divide are stressed store ATP

are stressed

Vibrioid-shaped cells derive their cell shape from _____. asymmetric cell wall growth the position of MreB proteins anchoring of periplasmic flagella asymmetric septation

asymmetric cell wall growth

In cocci, new peptidoglycan is deposited _____. at each cell pole randomly throughout the cell wall at the central septum

at the central septum

Penicillin-binding proteins (PBPs) function to link strands of peptidoglycan together and catalyze controlled degradation so that new units can be inserted during cell growth. The enzymes that hydrolyze peptidoglycan are called

autolysins

Which group of enzymes is required for limited peptidoglycan degradation, so that new units can be inserted during cell growth? Pencillins Autolysins Ribosomes Proteinases

autolysins

Microbes that can grow at high physical pressures are considered to be ______. compressotolerant osmotolerant barotolerant tensiotolerant

barotolerant

Broth cultures that are grown without the addition of fresh media are called _______ cultures.

batch

Broth cultures that are inoculated and allowed to grow without the addition of fresh media are called ______. batch cultures continuous cultures axenic cultures pure cultures

batch cultures

Streptococcus pneumoniae cells produce and release a small protein that at a high concentration induces some cells to _____. produce autoinducer molecules lyse and release their DNA to the medium become resistant to antibiotics become competent to uptake DNA

become competent to uptake DNA

Peptones are protein hydrolysates prepared from meat, soya, gelatin, and other proteins, and serve as sources of _____ in complex media. [Choose three.] nitrogen iron energy carbon pH buffer phosphorus

carbob nitrogen energy

Which polymer is not typically included in EPS? Glycolipids DNA Chitin Glycoproteins

chitin

A macroscopically visible cluster of microorganisms on a solid growth medium is called a(n)

colony

Halophiles can survive in extremely hypertonic environments by filling their cells with ______. water compatible solutes carbohydrates vacuoles

compatible solutes

Culture media that contain ingredients of unknown chemical composition are referred to as _______. selective differential complex defined

complex

True or false: Maximum growth temperature for an organism is invariable, a strict characteristic of each organism, determined by the properties of its molecular components.

false

Blood agar is an enriched medium that provides a broad range of nutrients and growth factors required for the cultivation of _____ microbes. hemophilic anaerobic fastidious acidophilic

fastidious

The length of time that it takes a culture to double in cell number is called the ______. viable time generation time reproductive time cell cycle

generation time

As a bacterial cell population increases in size, AHL moves _____ the cells. into out of

into

Radiation with very short wavelengths and high energies called ________ radiation is particularly damaging to cells.

ionizing

Breaking hydrogen bonds, destroying ring structures, and protein oxidation are among the cellular effects of _____. low pH high temperature ultraviolet radiation ionizing radiation

ionizing radiation

Autoinducers important for quorum sensing include N-acylhomoserine ______________. (This compound can easily diffuse across membranes and the concentration is dependent on the number of bacteria in the immediate area.)

lactone

When fresh growth medium is inoculated with a microbial culture there is typically a period of adaptation called the _______ phase.

lag

When fresh growth medium is inoculated with a microbial culture there is typically a period of adaptation called the ______. lag phase exponential phase death phase stationary phase

lag phase

The relationship between absorbance and cell concentration in the range of 0.1 to 0.5 absorbance units is _____. negative logarithmic linear

linear

An organism's optimal growth temperature is closest to its _____. minimal growth temperature usual growth temperature maximum growth temperature

maximum growth temperature

Numerous replicates of several dilutions of a culture can be used to estimate cell numbers in an approach called _________ number analysis.

most probable

Which of the following phenomena is observed during long-term stationary phase? photosynthesis natural selection fermentation

natural selection

The negative logarithm of the hydrogen ion concentration of a solution is its ______. pKa log H+ pH K of acidity

pH

The group of enzymes responsible for peptidoglycan synthesis are notable for their binding to ______. DNA polymerase penicillin autolysin microtubules

penicillin

The synthesis of peptidoglycan requires a group of enzymes called ______.

penicillin-binding proteins

The component of the bacterial cell envelope that protects the cell from swelling and bursting from turgor pressure is

peptidoglycan

Which three small molecules are compatible solutes typically found in halophiles? sodium chloride proline superoxide sucrose betaine potassium chloride

proline betaine potassium chloride

FtsZ placement determines the site of cell wall growth in cocci by _____. inhibiting enzymes for peptidoglycan synthesis, resulting in a spherical cell recruiting PBPs and other enzymes for peptidoglycan synthesis to the divisome directing enzymes for peptidoglycan synthesis to discrete bands around the outer membrane

recruiting PBPs and other enzymes for peptidoglycan synthesis to the divisome

Which two of the following adaptations are used by Halobacterium to survive in its environment? increase GC content of stable RNAs synthesize superoxide dismutase endospore formation stabilize cell wall with high concentration of sodium internal potassium concentration of 4M

stabilize cell wall with high concentration of sodium internal potassium concentration of 4M

Measuring turbidity or total protein of a culture can be used to estimate cell mass and thereby estimate population

size

In which three of the following are biofilms found? slime on rocks knee implants laboratory autoclaves on boat hulls

slime on rocks knee implants on boat hulls

Bacterial proteins that protect DNA, strengthen cell walls, and act as chaperones are often expressed during _____. septation oligotrophic growth biofilm formation starvation

starvation

RpoS is important for protein synthesis during ______. cell division starvation excystment eutrophism

starvation

RpoS is important for protein synthesis during ______. excystment eutrophism cell division starvation

starvation

The cloudiness of a broth culture that is indicative of microbial cells is called ________ and it can be measured using a spectrophotometer.

turbidity

One role of the cell wall in bacteria is to protect cells from bursting due to excessive ______.

turgor pressure

ppGpp is a signaling molecule, related to DNA and RNA nucleotides, that regulates the cell's response to _____. chemotaxis ionizing radiation biofilm formation stressors

stressors

General purpose media that sustain growth of many microbes are called _______. selective media supportive media differential media enriched media

supportive media

Halobacterium species require high salt concentrations. If the sodium concentration in the environment decreases too much, _____. the cell will synthesize flagella to move toward higher salt the plasma membrane will shrink the cell wall and plasma membrane disintegrate the cell will synthesize compatible solutes

the cell wall and plasma membrane disintegrate

Halobacterium species require high salt concentrations. If the sodium concentration in the environment decreases too much, _____. the cell will synthesize flagella to move toward higher salt the plasma membrane will shrink the cell will synthesize compatible solutes the cell wall and plasma membrane disintegrate

the cell wall and plasma membrane disintegrate

"The great plate count anomaly" refers to a discrepancy between _____. the number of cells observed by microscopy vs by plate counts the number of cells culturable in liquid vs solid media the number of cells observed by spread plating vs pour plating the number of pathogens vs the number of disease cases in the population

the number of cells observed by microscopy vs by plate counts

Microbes that grow at temperatures between 45 and 85°C are called

thermophiles

Streptococcus pneumoniae cells, in the competent state, are able to take up DNA from the environment, a process called _____. transduction transformation biofilm formation quorum sensing

transformation