MCB 3023 Final

Your page rank:

Total word count: 4767
Pages: 17

Calculate the Price

- -
275 words
Looking for Expert Opinion?
Let us have a look at your work and suggest how to improve it!
Get a Consultant

A food spoilage process called _____ results in the release of foul smelling amine compounds


Temperature and relative humidity are important intrinsic factors in determining the rate of food spoilage.


Filtration is sometimes used to remove organisms from beer because it has less effect on flavor than pasteurization.


Growth of yeasts and molds will be favored in more acidic foods.


Which of the following can function better at a lower pH?

Yeasts and molds

A major organism involved in the production of ergot is

Claviceps purpura

Ergotism involves microorganism production of

Hallucinogenic alkaloids

The first person to use heating processes to preserve food was

Nicholas Appert

The use of plastic film to wrap meat products can result in increased surface growth of microorganisms in part because of exposure to


Lysozyme is an important antimicrobial substance found at high levels in which food?


Microorganisms that grow in media with low water availability are called ____


Atmosphere is important in food spoilage; high H2S tends to reduce spoilage, while high CO2 tends to increase spoilage.



All of the choices (Is a small amphibilic peptide that disrupts membrane integrity and function, Is a food additive that blocks the growth of some gram positive bacteria, Is a bacteriocin produced by some strains of lactococcus lactis)

Which of the following represents ways in which canned foods can undergo spoilage?

All of the choices (Spoilage before canning, As a result of underprocessing during canning, Leakage of contaminated water through can seams during cooling)

A chemical that is effective in preserving foods with low pH such as bread is

Sodium propionate

Gamma irradiation has been used to sterilize certain types of foods. There are however certain limitations on its effectiveness. One of these is that it will only work on

Moist foods

Which of the following helps preserve food by controlling microbial access to water?

All of the choices (drying, addition of salt, addition of sugar)

Pasteurization of milk

Usually eliminates all disease-causing organisms

To control pathogenic and disease-causing organisms, spices can be fumigated using

Ethylene oxide

A major chemical used to preserve meat product is


Which of the following represents a different principle for food preservation?


The term radappertization is used to describe food preservation by

Gamma irradiation

Sometimes ____ beams are used to irradiate foods in place of gamma radiation because the process does not generate radioactive waste


The swelling of a food-containing can is usually due to the production of ___ by spoilage microbes.

Carbon dioxide gas

The conventional low-temperature holding procedure used in the pasteurization of milk involves holding the milk at 68.2 degrees C for ___ minutes.


To control microbial growth in a food, one can decrease water availability by adding

Sugar or salt

If food-borne disease transmission does not require growth of the microorganism after ingestion because the toxic substances are already present in the food as a result of previous growth then it is referred to as a food-borne ___


If food-borne disease transmission requires ingestion of the pathogen, followed by growth of the organisms and release of toxins in the intestine it is referred to as a food-borne ___


Staphylococcus aureus, once it grows in a food, produces toxins that are not usually inactivated by heating.


A major fungal genus that produces aflatoxin is


Aflatoxins are planar, ringed compounds that interact with DNA by ____ and cause frameshift mutations.


Clostridium botulinum and bacillus cereus are important disease-causing microorganisms of food which cause


A major organism considered to cause food-borne illness is


The largest meat recall in U.S. history was prompted by the discovery of contamination by

Listeria monocytogenes

Food-borne pathogens are most commonly identified by

Standard culture techniques

Which of the following is true about molecular detection of microoroganisms in foods?

All of the choices (detect presence of single specific pathogen + viruses that are not easily cultured + slow growing pathogens)

Pulsed-field gel electrophoresis can be used to link a particular pathogen associated with disease outbreaks in a specific food source.


The polymerase chain reaction can detect as few as 10 toxin-producing E. coli in a population of 100,000 microorganisms isolated from soft cheese samples.


The process of racking, used in the production of wines, involves

removal of sediments

The production of natural carbon dioxide by yeasts after a wine is bottled results in


The process of beer lagering involves


A microorganism that has been used in the production of sour mash whiskey is

lactobacillus delbrueckii

Bread products can be spoiled by the growth of Bacillus species that produce


Mashing is a process involving

Carbohydrate hydrolysis

Which of the following determines whether or not a wine is considered to be dry?

The amount of free sugar after fermentation

Streptococcus thermophilus and lactobacillus bulgaricus contribute to the flavor of yogurt by diacetyl during the fermentation of lactose.


Some fermented dairy products have been suggested to have beneficial effects, including a reduction in incidence of colon cancer and the minimization of lactose intolerance.


In all cases, it is necessary for disease causing microorganisms to grow in a food to result in a disease transmission to humans.


Mold-lactic fermentation results in a unique fermented milk consumed in Finland and called


Sequential growth of microorganisms in which the growth of one organism produces environmental conditions for the subsequent growth of another organism is called


In breadmaking, yeast growth is usually carried out under _____ conditions which results in more carbon dioxide production and less alcohol accumulation.


Which of the following microbial genera is used in the production of fermented dairy products?

All of the choices (streptococcus, lactobacillus, and leuconostoc)

The holes in swiss cheese are produced by the metabolic activities of which bacterial genus?


The science of wine production is called


A major cyanobacterial food source used in many parts of the world is


Feeding chickens a strain of Bacillus subtilis leads to

Increased body weight and feed conversion and a reduction in coliforms and Campylobacter in the processed carcasses.

When Lactobacillus acidophilus are sprayed on feed, the cattle that eat it appear to have markedly lower carriage of the pathogenic E. coli strain O157:H7


The approach of using mutagenesis and genetic selection to produce microbes with new degradative capabilities or the ability to produce compounds with new and unique properties is called _____ evolution.


The first penicillin-producing fungus that could be grown in stirred fermenters was

Penicillium chrysogenum

In the process of protoplast fusion, cells are grown in a medium that contains

Either lysozyme or chitinase, depending on the type of cells

The medium used in protoplast fusion experiments is


A major advantage of protoplast fusion is the fact that

Protoplasts of different microbial species can be fused

Primary metabolites

Are compounds needed for the synthesis of microbial cells in the primary growth phase

To assure maximum production of desired metabolites, it is always necessary to maintain organisms in active logarithmic growth.


Molecules produced by a cell that are not directly related to the synthesis of cell materials and that are usually produced after the growth phase has ended are called ______ ______

Secondary metabolites

To industrial microbiologists, fermentation means the mass culture of microorganisms.


Stirred _______ can range in size from 3 liters to 100,000 liters or larger, depending on production requirements.


Frequently a critical component in the medium, often the carbon source, is added ______ so that the microorganisms will not have excess substrate available at any given time.


Corynebacterium glutamicum is used for the large scale industrial production of

Amino acids

Penicillin is produced by some


Production of semisynthetic penicillins involves chemical modification of a penicillin product after it has been released from penicillin producing cells.


Although a small fraction of the citric acid used in the food and beverage industry is produced by microbial fermentation, most industrially used citric acid is derived directly from citrus fruit.


Microbially produced glycolipid surfactants are used for

Both emulsification and increasing detergency and solubilization of hydrophobic compounds.

Which of the following is a reason why bioconversions are replacing chemical synthesis of certain compounds?

Bioconversions yield specific and biologically active stereoisomers

Most biopolymers industrially produced by means of microorganisms are


Most antibiotics are produced by


The major organism used in the microbial production of citric acid is

Aspergillus niger

An amino acid that is used as a supplement for breads is


Corynebacterium glutamicum is used to produce glutamic acid, and this is most successful when the cell permeability is


Phenylacetic acid is added to the penicillin fermentation to allow incorporation of which side chain group?


The _____ lactose is often used as a substrate for penicillin production.


A major organism used in the biocontrol of a variety of types of insects is

Bacillus thuringiensis

A plasmid from the plant pathogenic bacterium _____ ______ is chiefly responsible for the successful genetic engineering of plants.

Agrobacterium tumefaciens

The Ti plasmid has been genetically engineered to improve its utility as a cloning vector by all of the following except

Genes responsible for resisting infection with B. Thuringeiensis have been added

Biosensors involve linking which of the following with electronic circuitry?

Both microorganisms and microbially derived enzymes

Diatom shell,s when incubated at 900 degrees C in an atomosphere of silicon for several hours, undergo an atom-for-atom substitution of magnesium with silicon without loss of three dimensional structure.


______ are formed by certain bacteria that convert iron to magnetite; these structures are of interest to _______ because they are despite the fact that they are perfectly formed despite the fact they are ony tens of nanometers in diameter.

Magnetosomes; nanotechnologists

In many ways, _____ as a biofuel compares very favorably to ethanol and other fuels.


Microorganisms do not generally reproduce sexually; therefore, species are usually defined by pheneotypic and genotypic similarities.


In an approach called _________ taxonomy, relatedness is determined by a wide range of phenotypic and genotypic information


Serovars are strains of a species that have distinctive antigenic properties


Microbial species are collections of strains that share many stable properties in common buffer but significantly from other strains


The type strain is a well-characterized strain to which other strains are compared for inclusion in or exclusion from a particular species


The type strain is the most representative strain of a particular species


Bacterial strains that are characterized by biochemical differences are called


rRNA signature sequences can be used to place microorganisms in the correct domain


The G + C content of a DNA sample can be estimated from its TM of a DNA


Conjugation is useful for determining relatedness between bacteria at the species level because it never occurs between organisms of different genera


Phylogenetic trees are usually constructed using either a distance-based (__________) approach, or a characteristic (____________) approach.

Phenetic, cladistic

Phylogenetic trees show inferred evolutionary relationships in the form of multiple branching lineages connected by nodes


Transformation is not useful in determining relatedness between two organism because it frequently crosses genera


The _________ hypothesis proposes that mitochondria and chloroplasts developed from free-living prokaryotes that invaded a precursor to the eukaryotes and established a stable relationship


Chromosomal gene exchange is not useful in classification because prokaryotes do not reproduce sexually


Extensive horizontal gene transfer between domains greatly simplifies thee construction of phylogenetic trees


The pace of evolution does not always occur at a constant rate but is periodically interrupted by rapid bursts of speciation; this is known as ___________ ____________

Punctuated equilibrium

Although there are other classification schemes for prokaryotes, the one used in Bergey’s Manual is currently considered by most microbiologists to be the most accurate


The second edition of Bergey’s manual group pathogenic species together rather than in phylogenetic groups


The scientific study of organisms with the ultimate goal of characterizing and arranging them in an orderly manner is


The assignment of names to taxonomic groups is referred to as


The determination of the taxon to which an organism belongs is called


The science dealing with classification is called


The arrangement of organisms into groups is best described as


A classification system based on mutual similarity that involves comparing as many characteristics as possible is called a _________ system


A classification system based on evolutionary relationships is called a _______ system


Which of the following is useful in biological systematics?

All of the choices (Physiology , Epidemiology, Ecology)

A general term used to describe groups based on mutual similarity or evolutionary relatedness is


A population descending from a single organism or pure culture isolate is called a


Which of the following is an example of the use of the binomial system devised by Linnaeus?

Escherichia coli

The organisms in which of the following are more closely related?


The binomial system of nomenclature assigns each organism a scientific name consisting of

Genus and species

The general order of classification below the domain or kingdom level is

Phyla, class, order, family, genus, species

Mole percent (G+C) of DNA is useful for determining relatedness at the _______ level


Stable annealing due to hydrogen bonding between DNAs of similar nucleotide sequence from different organisms is referred to as


The temperature at which half of the strands of a double-stranded DNA molecule have separated from each other is called that ________ temperature


Which of the following is not true about the G + C content percentages in DNA of organisms?

Organisms with similar G + C percentages have similar base sequences

Conserved indels are

A type of signature sequence particularly useful for phylogenetic analysis

The analysis of genetic relatedness by observing DNA fragmentation patterns resulting from restriction endonuclease cleavage is referred to as

Genetic fingerprinting

An unrooted tree contain four unrelated species can become rooted by adding

A distantly related outgroup

Small, random genetic changes that occur over generations is known as


According to genome analysis, a member of the genus _________ is most closely related to the mitochondrion


According to the endosymbiosis hypothesis

All of the choices (The first endosymbiotic involved an anaerobic bacterium, The first endosymbiont was a fermentative organism, The mitochondrion evolved from the same endosymbiont as the hydrogenosome)

The ancestors of modern ____________ performed the oxygenic photosynthesis responsible for converting our anoxic planet to an oxygenated one


A theoretical concept that issued to understand how and why certain organisms can be sorted into discrete taxonomic group sis known as the

Species concept

Which of the following is true about Bergey’s Manual?

The first edition is mostly phenetic while the second edition is more phylogenetic

The second edition of Bergey’s Manual classifies bacteria


What percentage of microbes have been cultured in the laboratory?


In the microdroplet culture method, cells from mixed assemblages are encapsulated in a gel matrix. The matrix is then emulsified to generate gel "micropdroplets"; each microdroplet contains a mixture of cells


A technique used to quantify specific types of microbes in natural samples, enrichment cultures and food or water samples is known as the ________ _________ _______ technique

Most probable number, MPN

_________ cultures are pure cultures, consisting of a single species


The use of modern molecular techniques has provided a mechanisms for growing the microorganisms previously referred to as unculturable


The discrepancy between the number of microbial cells observed by microscopic examination and the number of colonies that can be cultivated from the same natural sample may be due to

Nonviable organisms and incorrect culture conditions

____________ culture techniques are based in the expansion of the microenvironment to allow abundant growth of a microorganism formerly restricted to a small ecological niche


The fact that cells of genetically uniform populations do not have similar phenotypic attributes is called _________ heterogenerity


Optical tweezers can be used to

Study nucleic acids recovered from individual cells

Recent evidence suggests that most microbial communities have many individuals representing at least


Determining the functional nature of a microbial community by analysis of bulk DNA samples extracted from environmental samples may be misleading for all of the following reasons except

DNA is of little use in identifying unknown microbes

When PCR amplification of SSU (small subunit ribosomal RNA) yields a population of different PCR products of about the same molecular weight, these fragments can be separated for further analysis by

Denaturing gradient gel electrophoresis

When doing SSU (small subunit ribosomal RNA) of a mixed population of microbes from an environmental sample, specific _____________ are identified


It is generally agreed that SSU (small subunit ribosomal RNA) analysis is a technique that is well suited to identifying species present in a given community


Which of the following is microscopy in which the microscope is fitted with light filters that enable the excitation of the specific wavelength?

Epifluorescence microscopy

_________ ________ arrays are used to asses the diversity of a microbial population

Community genome

When fluorescently labeled oligonucleotides that are known to be specific to the microbe of interest are used to label natural samples, the technique is known as

Fluorescent in situ hybridization (FISH)

The fact that certain nucleotide templates are more readily amplified than others is termed

PCR bias

Phylogenetic oligonucleotide arrays (POAs) contain rRNA sequences as probes and are used as a means to detect complementary rRNA sequences from the environment


The level of specific mRNA, and therefore the expression of a given gene in a particular ecosystem, can be evaluated in the environment using situ reverse transcriptase (ISRT)-FISH


_____________ microbes are used to measure oxygen availability, UV radiation dose, pollutant or toxic chemical effects, and stress


The goal of ____________ is to identify each protein present in a given microenvironment at the time of sampling


The reporter gene most commonly used to monitor changes in the physical microenvironment for a single microorganism is the

Green fluorescence protein gene

Stable isotope analysis to indicate whether or not certain elements have been processed by an organism is based on the observation that

Microbes generally prefer using the lighter of two stable isotopes

In two-dimensional nano-liquid chromatography, a complex mixture of peptides is separated first by charge and then by solubility


Insects frequently contain bacteria in their cytoplasm, and these bacteria form mutualistic association with their host


Coral bleaching where the photosynthetic endosymbiont is lost or becomes non-functional can be caused by temperature increases as small as 20 Celsius


When two different microbes are engaged in a cooperative relationship, they do as well when living separately as they do when living together


In the host-parasite relationship, it is advantageous for the parasite to disable and kill its host as quickly as possible


A relationship in which one organism is found on the surface of another is referred to as a(n) __________________


The specialized structure in a tube worm in which endosymbiotic, chemolithotrophic bacteria live is called a(n) _______________


The term ___________ is used to describe a mutually beneficial association in which the growth of an organism is dependent on one or more growth factors, nutrients or substrates provided by another organism in the same vicinity


An example of microbial ___________ is the ability of Vampirococcus to attach to the outer membrane of its prey and then secrete degradative enzymes that result in the release of the prey’s cytoplasmic contents


_____________ is a beneficial relationship similar to mutualism, in which the relationship is not obligatory


A close physical relationship between two different species that may or may not be beneficial is called ______________


____________________ enzymes catalyze the hydrolysis of beta (1-4) linkages between successive D-glucose residues of cellulose


The loss of genetic information no longer needed for an intracellular existence by an obligate parasite is called genomic ____________


Any microorganism that spends a portion of its life associated with another organism of a different species is engaged in


Which of the following is not a category of symbiosis?


In commensalism

The host and commensal can be separated and remain viable

In mutualism

All of these (The mutualist is dependent on the host, A reciprocal benefit accrues to both partners, The partners will not survive separately in many case)

Which of the following is not part of the lichen association?

Brown algae

In a lichen, the fungal partner

All of these (Protects the alga from excess light intensities, Provides water and minerals to the alga, Provides a substratum within which the alga grows)

The reason coral reefs are among the most productive and successful ecosystems is due to

The coral-dinoflagellate mutualistic relationship

In the rumen, food is quickly attacked by cellulase

Enzymes produced by microbes

In the rumen, the carbohydrate fermentation end products include

All of these (Acetate, Carbon dioxide, Methane)

In lichens, the fungi send projections of their hyphae across the algal cell wall in order to obtain nutrients from the photosynthetic partner. These projections are called


The ectosymbionts of ruminant animals are useful to their hosts in which of the following ways?

All of the choices (They digest the cellulose of plant cell walls, They produce most of the vitamins needed by the ruminant, The convert glucose to organic acids)

A physical relationship where an organism hosts more than one symbiont is known as a


Buchnera aphidicola provides ________ to its aphid host that are essential to the survival of the insect

amino acids

The rickettsial parasite Wolbachia pipientis can

Sometimes alter the sex of an infected wasp

Dinoflagellates that exist endosymbiotically within a variety of marine invertebrates are called


Mussels and sponges sometimes contain methanotrops as intracellular symbionts because the methanotrophs

Convert methane to carbohydrate for the use by the host

Riftia tube worms make a unique kind of hemoglobin to

All of the choices (Transport oxygen, Transport hydrogen sulfide, To assist in the transport of carbon dioxide)

When Nitrobacter utilizes nitrite produced from ammonia by Nitrosomonas to obtain energy by converting the nitrite to nitrate, the relationship between the two organisms is


Methanogens are always engaged in relationships with other microbes because methane production requires

Interspecies hydrogen transfer

_________ is a predator that bores a hole through the outer membrane of its gram-negative bacterial prey and then reproduces in the periplasm


A unidirectional process where a specific compound released by one organism has a negative effect on another organism is called


Pseudonocardia is an organism that is hosted by

Ants that cultivate fungal gardens

____________ arises when different microbes within a population or community try to acquire the same resource


Microbes such as Lactobacillus acidophilus colonize the human vagina by fermenting


The average adult carriers 10 times more microbial cells (1014) than human cells (average about 1013)


Microorganisms commonly associated with the human body are traditionally referred to as the

Normal microbial flora or the normal microbiota

A __________ is any disease-producing microorganisms


A species of bacterium associated with the oil glands of the skin belongs to the genus


Which of the following would not find in the nasopharynx?

Branhamella catarrhalis

Which of following would you expect to find in the tonsilar crypts?


Microbiota of the skin are most likely to be found

In association with oil and sweat glands

Under normal circumstances, the microbiota of the skin is kept in check by

A slightly acidic pH

The term that refers to these microbes found as symbionts in a short relationship of a nongrowing nature is _____________


A bacterial genus that is found in large numbers in the intestinal tract of breast-fed infants is


Which of the following areas of the human is (are) not normally free of microorganism?

All of these (The ciliated epithelial cells, Lysozyme in mucus, Phagocytic action of alveolar macrophages)

Human sweat has antimicrobial activity due to

Production of an antimicrobial peptide called cathelicidins

Gram-positive bacteria such as Propionibacterium acnes limit the growth of gram-negative bacteria and some fungi on the human skin by converting secreted ___________ to compounds with antimicrobial activity


When members of the normal microbiota of the human body become pathogenic and produce disease under certain circumstances, they are referred to as ________________ pathogens


The lower respiratory tract has a normal microbiota


The lower genitourinary tract is usually free of microorganisms


The skin surface (epidermis) us a very favorable environment for colonization by microorganisms


Many anaerobic gram-negative bacteria are normally found in the duodenum


The oral cavity of humans normally becomes colonized with microorganisms within hours after birth


The condition in the host that results from pathogenic parasitic organism growing and multiplying within or on the host is called

An infection

The final outcome of most host-parasite relationships depends on

all of the choices (number of organisms present in or on the host, the virulence of the organism, the host’s defenses)

Which of the following has no effect on the outcome of the host-parasite relationship

all of these have an effect on the outcome of the host-parasite relationship (the number of parasites on or in the host, the virulence of the parasite, the defenses of the host)

Any organism that can cause disease in the host after direct interaction is a

Primary pathogen

An _______ pathogen can cause disease in a host with impaired resistance



Latent —-> Organisms present in tissue for long periods of time Antitoxin —> A neutralizing antibody Opportunistic —> Requires weakened immune system Localized —> Not general infection

If a symbiont either harms or lives at the expense of another organism, the relationship is called


An organism other than a human that is infected with a parasitic organism that can also infect humans is called a(n) ______ host.


Which of the following is required of a pathogen to possess in order for it to be successful at causing infectious disease?

All of the choices

An inanimate object that may be contaminated with a pathogen is called a


Which of the following is a facultative intracellular pathogen?

Brucella abortus

Transfer of pathogens from host to environment and then to another host are said to be transmitted _____.


A _______ infection is a disease cause by a parasitic organism that is normally found in animals other than humans.



Reservoir —-> site where the pathogen normally resides Formite—-> inanimate objects that may be involved in transmission Opportunistic —-> does not harm a healthy host Nosocomial—> develops during a hospital stay

Vector-borne transmission can be either external or internal. In internal transmission, the pathogen is carried

on the body surface of a vector

Inanimate materials involved in pathogen transmission are called reservoirs


Bacteria within biofilms exchange

All the above

Many types of bacteria are only ________ when dispersing from more stable and heterogenous communities known as biofilms


Virulence may be measured experimentally at the host level by the _______ which measures the number of pathogens that kills 50% of an experimental group of hosts within a specified amount of time.

Lethal dose 50

The term ______ refers to the degree or intensity of pathogenicity


Because LPS is bound to the surface of bacteria, it is called a(n) _______.


A neutralizing antibody against a toxin is called a(n) _______.


Exotoxins can be denatured by iodine to form ______ which are useful in vaccines


The capacity of an organism to produce toxin is called ________.


Many bacteria are pathogenic because they carry large segments of DNA called ______ ______ which were acquired by horizontal gene transfer, and which carry genes responsible for virulence

Pathogenicity islands

Once a pathogen has infected the host, _________ is a measure of the pathogen’s ability to spread to adjacent or other tissues


While exotoxin production is most generally associated with gram-positive bacteria, some Gram-negative bacteria also produce exotoxins


Macrophages are phagocytic cells


Fever responses can be triggered by an endogenous pyrogen called intereleukin-1


Colonization specifically refers to the multiplication of a pathogen on or within a host, and includes the resulting tissue invasion and damage


Generally, exotoxins tend to be more heat stable than endotoxins


The only organisms to produce endotoxins are gram-negative bacteria


Listeria monocytogenes propels itself through mammalian host cells using

Host cells actin and other cytoskeletal proteins

The toxic component of lipopolysaccharide is called

Lipid A

The characteristics of a pathogen that determine its virulence include which of the following

All of the choices (pathogenicity, invasiveness, and infectivity)

Pathogenicity islands are typically associated with

Genes encoding tRNA

Which of the following is not a biological effect associated with endotoxin


Endotoxin is released when

Gram negative pathogens lyse or divide

Which of the following is not a characteristic of Lipid A


Endotoxins include which of the following?


Share This

More flashcards like this

NCLEX 10000 Integumentary Disorders

When assessing a client with partial-thickness burns over 60% of the body, which finding should the nurse report immediately? a) ...

Read more


A client with amyotrophic lateral sclerosis (ALS) tells the nurse, "Sometimes I feel so frustrated. I can’t do anything without ...

Read more

NASM Flashcards

Which of the following is the process of getting oxygen from the environment to the tissues of the body? Diffusion ...

Read more

Unfinished tasks keep piling up?

Let us complete them for you. Quickly and professionally.

Check Price

Successful message