In microbiology the term growth usually refers to an increase in
a microbe's size.
the number of microbial cells.
the amount of ATP produced.
the number and size of microbial cells.
the number and size of microbial cells and the amount of ATP produced.
A cell that uses an organic carbon source and obtains energy from light would be called a
A(n) ______________ organism is one that requires oxygen for growth.
both aerotolerant and anaerobic
An aquatic microbe that can grow only at the surface of the water is probably which of the following?
Which of the following forms of oxygen is detoxified by the enzyme catalase?
All of the following are used to protect organisms from the toxic by-products of oxygen EXCEPT
A microbe that grows only at the bottom of a tube of thioglycollate is probably a(n)
Nitrogen is growth limiting nutrient for many organisms because
it is necessary for the biosynthesis of amino acids
it is required for synthesis of nucleotides.
it is required for lipid synthesis.
only a small number of bacteria are able to extract it from the atmosphere.
only a few microbes can extract it from the atmosphere, but all organisms require it for amino acid and nucleotide synthesis.
Which of the following growth factors would NOT be required by microbes which do not utilize electron transport chains?
At temperatures higher than the maximum growth temperature for an organism,
proteins are permanently denatured.
membranes become too fluid for proper function.
hydrogen bonds within molecules are broken.
hydrogen bonds are broken, and proteins are proteins are permanently denatured.
hydrogen bonds are broken, proteins are denatured, and membranes becomes too fluid.
Human pathogens are classified as
The term barophile refers to which of the following growth requirements?
Which of the following organisms would be most likely to contaminate a jar of pickles?
an obligate anaerobe
Organisms that can grow with or without oxygen present are
either facultative anaerobes or aerotolerant anaerobes.
A fastidious organism might be grown on which of the following types of media?
Obligate anaerobes may be cultured in the laboratory
in a reducing medium
in a candle
in standard Petri plates.
on blood agar plates
on blood agar plates in a candle jar.
Joan wants to discover a microbe capable of degrading an environmental contaminant. Which of the following refers to the process she should use?
A microbiologist inoculates a growth medium with 100 bacterial cells/ml. If the generation time of the species is 1 hour, and there is no lag phase, how long will it be before the culture contains more than 10,000 cells/ml?
An epidemiologist is investigating a new disease and observes what appear to be bacteria inside tissue cells in clinical samples from victims. The scientist wants to try to isolate the bacteria in the lab. What culture conditions are most likely to be successful?
culturing on blood agar plates
inoculation of EMB plates
incubation in a candle jar
inoculation of cell cultures
inoculation of a minimal medium broth
Which of the following measurement techniques would be useful to quantify a species of bacteria that is difficult to culture?
viable plate counts
MacConkey agar plates represent __________ medium.
both a differential and a selective
both a minimal and a selective
A Petroff-Hauser counting chamber is
a glass slide containing an etched grid for counting microbes directly using a microscope.
a device that counts cells as they interrupt an electrical current.
a device that measures the amount of light that passes through a culture.
an apparatus that traps bacterial cells on a membrane filter where they can be counted.
a device used to count numbers of bacterial colonies on a Petri plate.
Another term for the logarithmic growth of bacterial cells is
A device that removes wastes and adds fresh medium to bacterial cultures in order to prolong the log phase of a culture is called a(n)
A specimen of urine is determined to contain 30 bacterial cells per microliter. How many cells would be present in a milliliter?
Which of the following is NOT a direct method for measuring the number of microbes in a sample?
viable plate counts
During which growth phase are bacteria more susceptible to antimicrobial drugs?
the susceptibility is the same for all phases
The use of salt and sugar in preserving various types of foods is an application of which of the following concepts?
A clinical sample labeled as "sputum" was collected from
the central nervous system.
a piece of tissue.
The method of obtaining isolated cultures that utilizes surface area to dilute specimens is called
the pour-plate technique.
the streak-plate technique.
__________ are complex communities of various types of microbes that adhere to surfaces.
A colony-forming unit is the number of cells
in a colony.
that produces one colony.
in a particular specimen.
that is in exponential phase in a culture.
that can be placed on a Petri plate.
All of the following ingredients might be found in complex media EXCEPT
Sodium thioglycollate is associated with which of the following types of media?
Which of the following quantification techniques can distinguish living cells from dead cells in a culture?
a Coulter counter
During the __________ of growth, new cells are being produced at the same rate as other cells are dying.
During the __________ of growth, cells are dying faster than new cells are being produced.
When cells are metabolically active but not dividing, they are in the
Metabolic activity is at maximum level in the __________ of growth.
Cells are rapidly growing and dividing during the __________ of growth.
An organism that tolerates high __________ is called a halophile.
carbon dioxide levels
A capnophile is a microorganism that thrives in conditions of high __________.
A microorganism found living under conditions of high __________ is a barophile.
Microaerophiles are microbes that grow best at low
carbon dioxide levels.
An acidophile thrives under conditions of low
All of the following are associated with nucleic acid structure EXCEPT
Which of the following is found at the 5 end of a DNA strand?
a phosphate group
a hydrogen bond
a hydroxyl group
a methyl group
The bacterial chromosome is
found in a nucleoid
found in a nucleus.
both circular and found in a nucleoid.
both circular and found in a nucleus.
Which of the following types of plasmids allows a bacterial cell to kill its competitors?
Which of the following is NOT involved the packaging of eukaryotic chromosomes?
Which of the following statements is true of bacterial plasmids?
They are found in the nucleoid.
They can replicate autonomously
They carry genes for essential metabolic functions.
They are small circular DNA molecules.
They are small circular DNA molecules that can replicate autonomously.
break hydrogen bonds between complementary nucleotides.
synthesize short DNA molecules important for the function of DNA polymerase.
seal gaps between DNA fragments.
proofread DNA molecules.
assist in recognition of promoters during transcription.
Which of the following statements concerning transcription in bacteria is FALSE?
It occurs in the nucleoid region.
Sigma factors are parts of RNA polymerase that recognize promoter regions.
The same RNA polymerase transcribes primer RNA, mRNA, tRNA, and rRNA.
Termination is either self-induced or due to the presence of Rho protein.
There are a variety of sigma factors that affect transcription.
Which of the following is involved in translation?
both mRNA and tRNA
mRNA, rRNA and tRNA are all involved.
Which of the following is a characteristic shared by DNA and RNA polymerases?
efficiency of proofreading
type of nucleotides used
direction of polymerization
dependence on helicase
Which of the following is the strongest base pair?
both adenine-uracil and adenine-thymine
A codon is a particular combination of three nucleotides. Therefore, there are __________ possible combinations of the nucleotides A, C, G, and T.
The AUG codon functions in coding for the amino acid methionine and as a
marker for introns
recognition site for RNA polymerase
Which of the following must be removed from a eukaryotic mRNA molecule before it can be translated?
A charged tRNA first enters the ribosomal __________ site and then moves into the __________ site.
Which of the following statements regarding eukaryotic transcription is FALSE?
Transcription occurs in the nucleus, mitochondria, and chloroplasts (if present).
Multiple transcription factors are required.
There are four different RNA polymerases.
Multiple elongation factors are required.
A guanine is added to the 3 end, and a poly-A tail is added to the 5 end of the mRNA transcript.
Semiconservative DNA replication means that
each daughter DNA molecule is composed of one original strand and one new strand.
nucleotides are constantly being recycled as cells make DNA.
the cell can proofread its newly synthesized DNA only part of the time.
the sequence of a DNA molecule is preserved as it is being replicated.
each strand of a double-stranded DNA molecule is replicated differently.
Which of the following is NOT a characteristic of Okazaki fragments?
They are checked for accuracy by DNA polymerase III.
They make up the lagging strand of replicated DNA.
They begin with an RNA primer.
They are joined together by DNA ligase.
They are longer in eukaryotic cells.
The proofreading function of DNA polymerase III results in an error rate of __________ during DNA replication.
1 error in 1,000 bases
1 error in 100,000 bases
1 error in 1 million bases
1 error in 10 million bases
1 error in 10 billion bases
Which of the following processes is involved in the "central dogma" of genetics?
transcription and translation
DNA replication and translation
are active in the presence of a repressor
are generally anabolic pathways
are normally active
usually require an activator to be transcribed.
usually require a repressor to be transcribed.
Which of the following are considered to be frameshift mutations?
both inversion and insertion
both deletions and insertions
If the codon AAA is changed to AAG, it still codes for the amino acid lysine; this is an example of a
Which of the following causes mutations by creating thymine dimers?
DNA damage caused by ethidium bromide results in __________ mutations.
both inversion and insertion
both insertion and deletion
Which of the following is a DNA repair enzyme activated by visible light?
The Ames test proves that a chemical is
carcinogenic in Salmonella
mutagenic in Salmonella
carcinogenic in humans
mutagenic in humans
The horizontal transfer process known as transduction
involves a virus
involves a pilus
requires a cell to be "competent"
requires a plasmid
involves a mutagen
Frederick Griffith discovered
the lac operon
In conjugation, F+ cells
serve as recipient cells
contain an F plasmid
do not have conjugation pili
can transfer DNA only to other F+ cells
contain "jumping genes"
Another term for the palindromic sequence found at the ends of transposons is a(n)
Which of the following is characteristic of prokaryotic genomes but NOT eukaryotic genomes?
enclosed in nuclear membrane
typically consist of a few to several chromosomes
Genes are active in a region of the eukaryotic chromosome called
The energy required for DNA replication comes from
the leading strand
Which of the following is NOT involved in the regulation of the lac operon?
a repressor protein
Genetic elements known as promoters are initiation points in the process of
Codons are recognized during
__________ is initiated at sequences called origins
The process of __________ requires the activity of DNA ligase.
RNA polymerase is primarily responsible for
The process of __________ requires participation of tRNA molecules
The process of __________ is initiated with the incorporation of fMet.
Initiation of __________ involves Sigma factor molecules.
The process of __________ is described as semiconservative.
During __________, the growing polymer is located in the P site.
Standard methods of sterilization are not effective in inactivating
Which of the following statements is true of disinfectants?
Disinfectants are effective in destroying endospores.
Disinfectants are used on living tissue.
Disinfectants are used for sterilization
Disinfectants are used on inanimate surfaces.
Disinfectants are only effective for short periods of time (seconds to minutes).
Which of the following statements concerning microbial death is FALSE?
It can be used to evaluate the efficacy of antimicrobial agents.
It is constant over time of exposure to an antimicrobial agent.
It is the permanent loss of a microbe's reproductive ability.
It is the permanent loss of a microbe's ability to reproduce and can be used to evaluate antimicrobial agents
It is not an effective means of evaluating the efficacy of antimicrobial agents.
Which of the following is an example of sanitization?
A public toilet is treated with disinfectants.
A surgeon washes her hands before surgery
Heat is used to kill potential pathogens in apple juice.
An autoclave is used to prepare nutrient agar.
A nurse prepares an injection site with an alcohol swab.
free of all microbes
free of pathogens
Which of the following would NOT be bacteriostatic?
freezing below 0 degrees Celsius
refrigeration of mesophiles
Antimicrobial agents that damage nucleic acids also affect
the cell wall
the cell membrane
the viral envelope
Seventy percent alcohol is effective against
An instrument that will come into contact with only the skin of a patient should be disinfected with a(n)
degerming agent only.
germistatic agent only.
Which of the following is NOT an effective means of sterilization?
Which of the following describes flash pasteurization?
heating at 63°C for 30 minutes
heating at 72°C for 15 seconds
heating at 72°C for 15 minutes
heating at 134°C for one second
passing liquid through steam at 140°C
The dairy creamer used in restaurants is usually sterilized by
Boiling water for 10 minutes is effective in ridding it of
actively growing bacteria
both growing bacteria and enveloped viruses
Which of the following is NOT a feature associated with filtration?
nitrocellulose or plastic membrane filters
sterilization of heat-sensitive materials
varying thicknesses of membrane filters used
use of HEPA filters to filter air
ability of some filters to trap viruses and proteins
Which of the following is a target of pasteurization?
Which of the following types of radiation is nonionizing and has the shortest wavelength?
Which of the following is used for microbial control in fresh fruits and vegetables?
Which of the following can be used to disinfect air?
both HEPA and ultraviolet light
both ethylene oxide and ultraviolet light
Lysol is an example of which of the following groups of chemical antimicrobial agents?
Which of the following is the most appropriate pairing of microbe and biosafety level?
E. coli, BSL-3
methicillin-resistant Staphylococcus aureus (MRSA), BSL-2
Betadine is an example of which of the following groups of antimicrobial agents?
Which of the following statements about quaternary ammonium compounds is FALSE?
They are a type of detergent.
Zephiran is an example of a quat.
They are not effective against Pseudomonas aeruginosa.
They function by cross-linking proteins.
They are harmless to humans except at high concentrations.
Which of the following is a sterilizing agent?
ozone and hydrogen peroxide
Which of the following was used in the past to prevent the transmission of gonorrhea from an infected mother to her newborn?
Which of the following is used to sterilize items that should not, or cannot, be exposed to heat or water?
Which of the following statements about aldehydes is FALSE?
They are used only to preserve dead tissues.
They denature proteins.
Some aldehydes can sterilize after long periods of exposure.
They are usually hazardous to humans.
They are used in aqueous solutions.
Disinfecting agents naturally produced by microorganisms are
A chemical agent that kills pathogenic microbes in general is a(n)
Which of the following is NOT a desirable characteristic of an ideal antimicrobial agent?
It is inexpensive
It is stable during storage
It is harmless to humans
It only arrests grows of vegetative cells.
It acts quickly
The endospores of which of the following microbes are used to measure the effectiveness of autoclave sterilization?
A scientist develops a new medication that is a protein compound and that must be administered by injection. Which of the following would be the most effective and safest means of preparing a sterile solution of the new medication?
dilution with alcohol
Which of the following procedures is currently the standard test used in the United States for evaluating the efficiency of antiseptics and disinfectants?
microbial death rate
thermal death point
Which of the following would be used to sterilize a mattress?
Disinfectants that damage membranes include
both alcohol and phenolics
Which of the following antimicrobial agents is the most toxic to humans?
70 % alcohol
The process of filtration is a(n)
ineffective method for removing microbes.
Hydrogen peroxide is a(n)
disinfecting and sterilizing agent.
ineffective method of disinfecting.
The process of incineration is used for
both disinfection and sanitization
Alcohols are used for
both sterilization and disinfection.
both antisepsis and disinfection.
The chemical agents known as "quats" are used for
quantifying antimicrobial activity
neither antisepsis nor disinfection
The compound ethylene oxide is used in
Glutaraldehyde is used for
both disinfection and sterilization.
__________ may be achieved using chlorine dioxide.
Both antisepsis and degerming
Gamma irradiation is a process for
__________ can be accomplished using boiling water.
Both disinfection and sanitization
Obligate anaerobes have enzymes such as superoxide dismutase to protect them from the damaging effects of oxygen.
Nitrogen fixation is a process that occurs in all bacteria.
Thermoduric mesophiles are often responsible for spoilage of improperly canned foods.
An obligate halophile will burst if placed in freshwater.
The only effective way to store bacterial cultures for short periods of time is to arrest their metabolism by freezing.
Quorum sensing is a process by which bacteria respond to the density of other bacteria in their environment.
An obligate anaerobe can be cultured in a candle jar.
Agar is a useful compound in the microbiology lab because it is an excellent nutrient for bacteria.
A selective medium can be formulated either by including inhibitory chemical substances or by leaving out a single crucial nutrient.
In spectrophotometry, 40% light transmission is the same thing as 60% absorbance of light.
Prokaryotic cells are diploid.
Prokaryotes have one type of DNA polymerase, which is different from that of eukaryotes.
The most common type of mutation is a point mutation.
Most bacteria have a natural ability to take up DNA from their environment.
The structure of DNA explains both its ability to encode genetic information and the way in which it is copied during cell reproduction.
DNA, which is negatively charged, wraps around positively charged histones as part of the packaging of eukaryotic chromosomes.
Bidirectional replication means that each strand of a DNA molecule is replicated in the opposite direction from the other.
The phenotype of an organism reflects only part of its genotype.
In generalized transduction, viruses carry random DNA sequences from one cell to another.
DNA polymerase III participates in the dark repair mechanism of DNA mutation repair.
An environment may contain some microbes and still be considered sterile.
Some viruses are inactivated by the same chemical or physical agents that damage cytoplasmic membranes.
UV light has the most effect on protein structure.
Antimicrobial agents usually work best at high temperatures and pH levels.
The phenol coefficient is one of the most widely used measurements of an antimicrobial agent's effectiveness.
No chemical or antimicrobial agents inactivate prions.
The decimal reduction time is the time required to kill all the microbes in a given sample.
Slow freezing is more damaging to microbial cells than quick freezing.
Hydrogen peroxide is an effective antiseptic.
By themselves, soaps have only degerming activity, not antimicrobial activity.