Micro FINAL!!!!
Controlling microbial growth is important in which of the following scenarios?
Preparing a patient for surgery manufacturing of food products caring for an open wound
Light microscopes that are routinely used in the laboratory can magnify images about ____.
1,000 X
Resistance to antimicrobials can result from the alteration of existing genes via spontaneous mutation, or via horizontal ____ transfer from another organism.
GENE
The principle that certain microbes cause diseases is called the ____ Theory of Disease
Germ
a broth media with the addition of agar, an extract of marine algae.
agary
What is the 3rd substance used in a gram stain?
alcohol
Fungi associate with ______ to form lichens.
algae and cyanobacteria
Which of the following are eukaryotes?
algae, fungi, helminths, and protozoa
A sterile object is free of ______.
all viable microorganisms and viruses
What are four common mechanisms of acquired resistance to antimicrobial medications?
alteration in the target molecule increased elimination of the drug production of a drug-inactivating enzyme decreased uptake of the drug
protein synthesis
aminoglycosides
_______ move by extending and retraction portions of their cytoplasm.
amoebae
An environment with little or no O2 present is called a(n)
anaerobic environment
Which of the following statements best describes protozoa?
animal-like unicellular organisms
Immunofluorescence uses a(n) ____ that has a fluorescent compound to tag a specific protein.
antibody
Which type of microscope transmits a light through a specimen in order to illuminate the field of view evenly?
bright-field microscope
Antimicrobials that are effective against a wide range of bacteria are known as
broad-spectrum antimicrobials
liquid media
broth
In general, yeast cells reproduce asexually by a mechanism called .
budding
How do aqueous solutions of alcohol usually affect microbes?
by damaging lipid membranes by denaturing proteins
Animal viruses ______.
can only be grown in animal cells
The consequences of not repairing damaged DNA in cells include ____
cancer (in animals) cell death
A distinct, thick gelatinous material that surrounds some microorganisms
capsule
Cancer-causing chemicals are called
carcinogens
Chemicals that cause cancer are known as ______, and most of them are ______.
carcinogens; mutagens
Oncoviruses are viruses that can ______.
cause cancer in humans
Which organization recently published a document that lists the most serious threats with respect to antibiotic resistance?
cdc
Although live animals and fertilized chicken eggs have been used to cultivate animal viruses in the past, these have now been largely replaced by
cell culture
Tumors are abnormal growths that result from a malfunction in the regulation of ______.
cell growth
Adding sorbic, propionic, and benzoic acid to foods affects ______ of microbes.
cell membrane function
Which structure provides strength and rigidity to a cell?
cell wall
Peptidoglycan is found in the ___.
cell walls of bacteria
Viable cell counts determine the number of ______.
cells capable of multiplying
A worm with a flat, ribbon-shaped body, and no digestive system is called a tapeworm or
cestode
Cell walls contain chitin and glucan cell membranes contain ergosterol no flagella
characteristics of fungi
antimicrobial chemical
chemical method of control
Antimicrobial medications (also referred to as antimicrobial drugs or simply antimicrobials) are best defined as ______.
chemicals that inhibit the growth of or kill microorganisms
A continuous culture system that adds nutrients and removes waste in order to maintain a constant growth rate and cell density is called a
chemostat
Which device is used to keep cells in a state of constant growth?
chemostat
Movement of a cell toward or away from a certain chemical in the environment.
chemotaxis
fungi have ____ in their cell walls.
chitin
Fungi differ from most other eukaryotic organisms in that their cell walls contain____ , and their cell membranes contain ____
chitin; ergosterol
found in all eukaryotes and prokaryotes
chromosomes only
In general, the chromosome of a bacterial cell is a _______ DNA molecule that is replicated _______.
circular; bidirectionally from one origin of replication
Protease inhibitors are used to treat HIV infections by inhibiting the HIV-encoded protease, preventing it from ______.
cleaving the translated polyprotein into individual parts
The two most common examples of endospore-forming genera are
clostridium, bacillus
short rod
coccobacillus
spherical
coccus
An isolated ____ is a distinct mass of microorganisms appearing on a solid medium, arising from the multiplication of a single cell.
colony
a group of bacteria, fungi, and other microbes grown on a solid agar media.
colony
If the counterstain step is not done in the Gram stain, how would Gram-negative bacteria appear?
colorless
A bacterial cell described as _____ can take up DNA from the surrounding environment.
competent
Cells that have the ability to take up DNA from the environment are called ______ cells.
competent
Because viruses have no cell wall, ribosomes, or any other structure targeted by antibiotics, viruses are ______.
completely unaffected by antibiotics
Technically speaking, viruses are not microorganisms because they are not ___.
composed of cells.
Difficult to reproduce in a laboratory
conditions in close microbial associations
All of the following are examples of mechanisms of acquired antimicrobial drug resistance EXCEPT ______.
development of a mutation in response to an antimicrobial
Gram stains and acid-fast stains are ____ stains, meaning they are multi-step procedures using two dyes to distinguish different groups of microorganisms.
differential
The Gram stain is an example of a(n) ____ stain because it separates bacteria based on their cell wall structure?
differential
Which staining process relies on the use of two stains?
differential stain
A fungus that can grow as single yeast cells or multicellular hyphae, depending on environmental conditions, is said to be a(n) ____ fungus.
dimorphic
Fill in the blank question. Mutants that can grow under conditions in which the parent (wild type) cells cannot are easily isolated by ____ selection.
direct
Selecting penicillin-resistant mutants by plating them on a medium containing penicillin is an example of ______ selection. Multiple choice question.
direct
Fill in the blank question. Mutant cells in bacterial cultures can be isolated by ____ selection and ____ selection methods.
direct; indirect
After sulfa drugs and penicillin were introduced, people hoped such drugs would eliminate most bacterial diseases. Unfortunately, this has not happened. Why is this?
drug resistance limits the usefulness of all known antimicrobials
administered through intravenous or intramuscular injection
drugs that are unstable at a low pH
drugs that are unstable at a low pH
drugs that can cross from the blood into the cerebrospinal fluid
Bacteria growing in a natural environment experience ______.
dynamic and complex conditions
Some bacteria can become resistant to an antibiotic by exporting it across the cell membrane. This is most likely due to
efflux pumps
Radio waves, X-rays, microwaves, UV light and gamma rays are all examples of ______.
electromagnetic radiation
What form of microscopy is used to observe virus structure?
electron
The process by which a virus is taken up by a host cell as a result of the host cell's cytoplasmic membrane surrounding the virion to form a vesicle is called ______.
endocytosis
An extraordinarily resistant dormant cell produced by some types of bacteria
endospore
____ are flatworms with just one opening, a mouth, and two suckers for attachment to and movement along their host.
flukes
are flat and leaf-shaped Have 2 suckers Have a mouth but no anus
flukes
Adding preservatives such as benzoic acid to food is important because ______.
it inhibits the growth of many bacteria and mold
The majority of antifungal drugs target ergosterol. Why is this so?
it is a sterol found in the cytoplasmic membrane of fungal, but not human, cells
Which of the following describes the optimum temperature of a psychrophile relative to a thermophile?
it is lower than a thermophile
Because nucleic acid synthesis is a common feature of all eukaryotic cells, it is generally a poor target for antifungal drugs. How is the drug flucytosine able to effectively target this process in yeast versus human cells?
it is taken up by yeast and converted by yeast enzymes to an active, inhibitory form
Antibacterials like daptomycin and polymyxin B essentially make holes in the bacterial membrane. Why, in terms of the function of the membrane, is this deadly to bacteria?
it makes the membranes no longer selectively permeable
Viral genome remains silent within the cell
latent state
A light microscope uses variable light and a series of ____ to magnify objects
lenses
Microorganisms that are free living are ______ to chemical disinfectants than microorganisms in a biofilm.
less resistant
Because of concerns about antibiotic resistance, the CDC published a document that lists the most serious threats, categorizing them by ______.
level: urgent, serious, and concerning
A life form commonly found on rocks that results from a symbiotic relationship between a fungus and a photosynthetic microorganism is called a(n) .
lichen
What defines spontaneous generation?
life arose from non-living matter
Bacteria use gas vesicles to float to the surface of water to better access ____ as a source of energy.
light
Which two macromolecules are the major components of cytoplasmic membranes?
lipids; proteins
Molecule that makes up the outer layer of the outer membrane of Gram-negative bacteria.
lipopolysaccharide
Animal viruses can be studied by infecting ______
live animals cell or tissue culture Fertilized chicken eggs
taken infrequently, often only once a day or less
long half life
A solution of sodium hypochlorite is more effective against bacteria at _______ pH.
low
The minimum inhibitory concentration (MIC) is the ______.
lowest concentration of a specific antimicrobial drug needed to prevent the growth of a given bacterial strain in vitro
Infection of bacteria by ____ phages always ends with the lysis of the host cell.
lytic (virulent)
____ is transcribed from a DNA template and translated during protein synthesis
mRNA
How do electron microscopes differ from light microscopes?
magnification is higher
Soap generally does not destroy most microbes, but it aids in their ______.
mechanical removal
Washing hands with plain soap and water works by ______ removing microbes.
mechanically
collection of nutrients and other substances. There are several kinds. Liquid media called broth and solid media called agar.
medium
The analysis of the total microbial genomes in an environment is a field known as
metagenomics
Study of organisms too small to be seen by the human eye
microbiology
Organisms that populate the human body and which protect it from disease are termed normal ____.
microbiota
The Germ Theory of Disease states that___.
microorganisms cause certain diseases
Use of light or elements to magnify objects
microscopy
The lowest concentration of a specific antimicrobial drug needed to prevent the growth of a given bacterial strain in vitro is known as the ____ _____ concentration.
minimum inhibitory
type of point mutation resulting in an amino acid substitution
missense mutation
filamentous fungi
molds
Which of the following are microscopic fungi?
molds, yeasts, and protists
Household bleach applied at 55C is ________ effective in killing bacteria than if it were applied at 50
more
The terms yeast, mold, and mushrooms refer to fungal _______.
morphology
reproductive structures of certain fungi
mushrooms
A(n) _____ is a change in the nucleotide sequence of DNA that is passed on to daughter cells.
mutation
Genetic change in bacteria occurs through which two mechanisms?
mutation horizontal gene transfer
stable heritable changes in the DNA sequence
mutations
The term ____ is used to describe a disease caused by a fungus growing on or in the human body.
mycosis
The smallest virus is approximately 10 ______ in diameter.
nanometers
Organisms most fit to survive in a given environment will predominate because they can reproduce more rapidly than others. This phenomenon is called ____ _____.
natural selection
The process by which organisms best adapted to a given environment will predominate in that environment is called _______.
natural selection
Made of double stranded RNA
neither plasmids nor chromosomes
A worm with a cylindrical, tapered body with a digestive tract that extends from the mouth to the anus is called a roundworm or
nematode
type of point mutation that changes an amino acid codon to a stop codon
nonsense mutation
All DNA nucleotides contain the same deoxyribose and phosphate group, but different ______
nucleobases
In prokaryotes, the cell's chromosome is found in a region of the cytoplasm called the ____
nucleoid
In prokaryotes, the cell's chromosome is found in a region of the cytoplasm called the ____.
nucleoid
A patient has a urinary tract infection. Why is this a good example of an infection that can usually be treated well with bacteriostatic antimicrobials, e.g., sulfa drugs?
once bacterial growth is stopped, urination can usually be counted on to flush the pathogens
Viruses that specifically target and kill cancer cells are called
oncolytic viruses
To treat a case where the patient's defenses are unlikely to clear an infection, which would be the more appropriate choice of an antimicrobial drug, one that is bactericidal or bacteriostatic?
one that is bacteriocidal
A long stretch of DNA that potentially codes for a protein is called a(n)
open reading frame
a species grows most rapidly at its
optimum growth temperature
Specific starting point of replication
origin of replication
Which of the following is a component of Gram-negative cells but not Gram-positive cells?
outer membrane
Some microorganisms produce acids during metabolism. Which of the following would be a strong indication of this activity?
pH of the culture medium should be lower after growth
Medically important helminths are ______.
parasitic worms that can invade human tissues
A(n) ____ is a term used for any disease-causing microorganism
pathogen
In general, disease-causing organisms are referred to as which of the following?
pathogens
The first antibiotic,____ , was discovered in 1928 by Alexander Fleming.
penicillin
A macromolecule that provides strength to the cell wall; it is only found in bacteria.
peptidoglycan
The gel-like material that fills the region between the cytoplasmic membrane and the outer membrane of gram-negative bacteria and the cytoplasmic membrane and peptidoglycan layer of at least some gram-positive bacteria
periplasm
In which type of infection does the virus remain in the host for years, sometimes without symptoms?
persistent
The ability of Escherichia coli to randomly turn on or off the the production of attachment pili is an example of ______.
phase variation
Repair of nucleotide incorporation errors during the process of DNA replication is accomplished by _____ by DNA polymerase and by _____ repair.
proofreading; mismatch
The most common type of mutation is base ______, where an incorrect nucleotide is incorporated during DNA replication.
substitution
metabolic pathways (folate biosynthesis)
sulfanomides
The cell wall of Gram-positive bacteria is characterized by
thick layer of peptidoglycan
Human cells are larger than viruses by which size factor?
thousand
What long protein structures are responsible for most types of prokaryotic motility?
flagella
A type of structure used for cell movement
flagellum
You are viewing a specimen with a 10x eyepiece and a 40x objective lens. What is the total magnification?
400x
Lack of an oxygen molecule at the #2 carbon sugar. That is what makes it deoxy
5 carbon sugar deoxyribose
Aqueous solutions of alcohol at a concentration of ______ are more effective than 100% alcohol.
60-80%
Eukaryotic cells have 80S ribosomes. Prokaryotic cells, however have ____ribosomes, composed of a 50S and 30S subunit. The structure of these prokaryotic ribosomes is different enough from the eukaryotic ones that they can be selectively targeted by antibacterial drugs
70S
Why is regulation of gene expression important?
A cell does not need all of its encoded proteins at the same time
Nitrogenous bases
A,T,G,C
Active transport moves compounds against their concentration gradient. The form of energy used for this purpose is either ___ or the __ __
ATP; proton motive
Because CRISPR systems involve bacteria using retained segments of DNA to identify and destroy future invading phage DNA, these systems are a form of ______.
Adaptive immunity
Which of the following are eukaryotes?
Algae, arthropods, fungi, multicellular worms
Who is credited with creating the first "microscope" and observing microbes?
Antoni Van Leeuwenhoek
List the steps of an animal virus infection cycle in the correct order. Start with the earliest at the top.
Attachment Penetration and Uncoating Synthesis of viral proteins and replication of the genome Assembly Release
Why do descriptions of cell structure often lump bacteria and archaea together?
Bacteria and archaea are both prokaryotic
A common dry heat sterilization method used in the microbiology laboratory is ______.
flaming the inoculating loop
_______ is a roundworm (nematode) that serves as a model eukaryotic organism. Its genome has been sequenced and all of its 959 body cells can be identified
Caenorhabditis elegans
The prokaryotic cell envelope consists of which of the following?
Capsule, Cell wall, Cytoplastic membrane
Why are cells growing in a colony on solid media likely to be in many more different phases of growth than cells growing in liquid culture?
Cells in liquid culture experience a relatively uniform environment, so they are much more likely to be in the same phase of growth. Unlike cells on the edge of a colony, those in the center of a colony face depleted levels of nutrients and O2, yielding different phases of growth
If both glucose and lactose are present in a medium, why is the lac operon not transcribed?
Cells preferentially use glucose and only use lactose if the glucose is depleted
Which of the following species are the four major producers of antibiotics?
Cephalosporium (fungus) Streptomyces (bacterium) Penicillium (fungus) Bacillus (bacterium)
The main difference between the nucleoid and the nucleus is that the nucleoid ______.
is not membrane-bound
Which of the following does not describe interactions of mixed microbial communities?
Conditions in mixed microbial associations are readily reproduced in the laboratory
What did Lazzaro Spallanzani do?
Contradicted Needham. No bacteria in his broth after boiling. His experiment differed by broth boiled longer, and sealed flasks by melting neck. Disproved spon. gen. Still needed more evidence.
What is the order of reagents used in the Gram stain procedure? Starting from left to right
Crystal violet, iodine, alcohol, safranin
An essential macromolecule that encodes all of the information needed by a cell to synthesize its components is ___
DNA
The molecule that encodes all the instructions needed to produce a cell's components is ______.
DNA
Central dogma of molecular biology
DNA -> RNA
During repair of oxidized guanine, which enzyme removes the damaged nucleobase from the sugar-phosphate backbone?
DNA glycosylase
In humans, two of the genes associated with the development breast cancer encode enzymes involved in ______.
DNA repair
Which of the following are functions of membrane transport systems?
Expel wastes from cell Allow nutrients to enter cell
When an excision errors produces a plasmid containing both chromosomal and F plasmid DNA, the resulting plasmid is called a(n) ____ plasmid
F'
Which of the following are physical ways to remove or destroy microbes?
Filtration Ultraviolet radiation Autoclaving Incineration
What did Louis Pasteur do?
Finally disapproved spon. gen. with his "swan neck" experiment. Led to theory of biogenesis.
What did John Needham do?
Found that broth gave rise to microbes even when boiled and sealed with cork. Proved spontaneous generation. flawed.
What did Francesco Redi do?
Found that worms rotting on meat came from eggs and not spontaneous gen.
Although generally less reliable than heat, germicidal chemicals are especially useful for treating ______.
Heat-sensitive items large surfaces
Why is it much more difficult to develop drugs that will effectively control fungal pathogens than it is to control bacterial ones?
Humans and fungi are both eukaryotes, so antifungal drugs are likely to have adverse effects on the human as well
One of the most dramatic examples of antimicrobial resistance are the enterococci, a group of bacteria that is part of the normal microbiota of the ______ and a common cause of healthcare-associated infections.
INTESTINE
In what ways is microbial growth in a colony the same as growth in a liquid?
In both cases, cells compete with one another for available nutrients. Both involve a lag phase followed by exponential growth
Typically, most fungi grow ______.
In the presence of O2 between 20 to 35 C Terrestrial environments
Which of the following describe selective media?
Inhibit the growth of certain species allow the growth of desired organims
A batch culture has which of the following characteristics?
It is a closed system Wastes not removed It typically involves growth of bacteria or archaea either on agar plates or in tubes or flasks of broth. Nutrients not renewed.
The study of bacteriophages has advanced much faster than investigations on animal viruses in part because ______.
It is easier to grow bacterial cells than animal cells
Which of the following about classifying viruses is FALSE?
It is not as important as classifying organisms since they are not living entities
Which is the best general description of a medium used to support bacterial growth in a Petri dish?
It may have very few nutrients, or it may have many different nutrients to support widely varying growth requirements.
The endospore stain ____.
is useful for identifying a few bacterial genera
____ is credited with disapproving spontaneous generation and using broth in swan-neck flasks
Louis Pasteur
____ phages cause productive infections that do not kill the host cell.
Lysogenic
Although antimicrobial resistance can result from the acquisition of new genes, it can also be due to the altering of existing genes via spontaneous _____
MUTATION
Microorganisms are useful in the study of higher life forms for which of the following reasons?
Microorganisms are cheaper to study Microorganisms have the same fundamental genetic properties Microorganisms multiply quickly Microorganisms have the same basic metabolic mechanisms.
Why do microorganisms serve as important models for study of higher organisms?
Microorganisms have the same fundamental metabolic and genetic properties of other organisms.
Which of the following statements about the influenza pandemic of 1918-1919 are true?
Most americans died of influenza than WWI & II and the korean, vietnam, and iraq war combined
Compared with antibacterial, antifungal, and antiviral drugs, why does relatively little research and development go into antiprotozoan and antihelminthic drugs? Multiple choice question.
Most parasitic diseases are concentrated in the poorer areas of the world where people simply cannot afford to spend money on expensive medications.
Which of the following molecules can freely pass through the phospholipid bilayer?
O2, CO2, water, small hydrophobic particles
What did Leuwenhoek do?
Observed what he called "little animalcules" First observer of microorganisms Created the first microscope.
To initiate replication of a DNA molecule, specific proteins must bind to a specific DNA sequence called the ______.
Origin of replication
In 1928, Alexander Fleming noticed that colonies of Staphylococcus aureus growing near a contaminating mold looked as if they were dissolving. He identified the mold, which was producing the first discovered antibiotic, as a species of _____.
Penicillium
Most bacteria have a rigid cell walls that contain a compound called ____.
Peptidoglycan
Which of the following describe a type of relationship that bacteriophages can have with their host?
Productive lytic infection Latent infection where host cell genotype is changed
The active transport system shown here is using the energy of the ___ ___ ___ to move a substance against the concentration gradient
Proton Motive Force
Consider the use of low temperature storage for the preservation of food. Which of the following are accurate statements?
Psychrotrophic and some psychrophilic microorganisms can grow at refrigeration temperatures. Refrigeration inhibits the growth of many pathogens and spoilage microorganisms by slowing or stopping critical enzyme reactions.
Microbial cells must maintain a near-neutral internal pH. Because of this, bacteria that grow in acidic environments have mechanisms to
Pump out H+ that enter the cell
Transcription is carried out by an enzyme called
RNA polymerase
What enzyme binds to a DNA promoter region to initiate transcription?
RNA polymerase
During transcription, RNA polymerase synthesizes ______ from a(n) ______ template.
RNA; DNA
Which of the following are systems bacteria can use to protect against invading DNA?
Restriction-modification CRISPR
Extensively damaged DNA activates the ___ repair mechanism, which cannot always determine the correct nucleotide sequence, thus introducing mutations resulting from the repair process itself.
SOS
______ repair is activated by extensive DNA damage and uses a polymerase that lacks proofreading ability, ultimately resulting in mutations.
SOS
What were past microbiology triumphs?
Smallpox eradicated Plague deaths <100 per year Polio nearly eliminated by vaccine.
After testing to determine the susceptibility of an organism to various drugs, what are important considerations when choosing a drug to use?
The drug should act against as few other bacteria as possible The drug should act against the pathogen
Consider the following environmental factors. Which have the most impact on microbial growth?
Temperature Oxygen availability pH water availability
What came after spontaneous gen was disapproved?
The golden age of microbiology
Which of the following is found in all DNA nucleotides?
The same phosphate, but different nucleobases
Which answer best explains the events in the figure leading to plasmolysis?
The solute concentration of the medium is greater than that in the cell, causing water to diffuse out of the cell due to osmosis.
Some protozoan species can exist as a trophozoite or as a cyst form. How are these forms best described?
The trophozoite is a growing, feeding form. The cyst is an infectious survival form
Which describes the various laboratory media used to cultivate bacteria?
They are diverse in nutrient content and consistency
How are liquid batch cultures most often aerated to support the growth of aerobic microbes?
They are grown in tubes or flasks that are shaken continuously
Effective antimicrobial drugs would need to demonstrate selective toxicity. What does this mean?
They cause greater harm to microbes than to the human host
Why were Louis Pasteur's experiments with swan-necked flasks so important in helping disprove the theory of spontaneous generation?
They ended an argument that a "vital force" was necessary for spontaneous generation, while preventing contamination from microbes in the air.
What is a special consideration when giving antimicrobials to patients who have kidney or liver dysfunction?
They may excrete or metabolize drugs more slowly, so their dosages should be adjusted accordingly to avoid toxic levels
Contains an origin of replication
both plasmids and chromosomes
Which of the following processes are required for production of virus particles in a host cell?
Transcription of viral genes Translation of viral genes Replication of viral genome
What is the proper order of the following events in the expression of a eukaryotic gene?1. translation2. RNA processing3. transcription
Transcription, RNA processing, translation
Which of the following statements about transformation is correct?
Transformation is the uptake of naked DNA from the environment
___________ is the process of decoding the information carried by mRNA to synthesize a protein
Translation
How might an enrichment culture be used to isolate organisms capable of nitrogen fixation?
Using a media that does not contain any form of nitrogen, and exposing it to the atmosphere
Many enterococci have R plasmids; some strains, called _____ - _____ _____, are even resistant to vancomycin.
Vancomycin-resistant enterococci
Which of the following statements about viruses are true?
Viruses contain RNA or DNA but not both. The viral capsid is composed of protein
Which of the following about microorganisms is true?
We could not survive without them
Infectious agents that have a simpler structure than viruses include ______.
both viroids and prions
Restriction-modification systems were discovered ______.
While studying why certain bacterial strains are relatively resistant to phage infection
Which of the following types of radiation are mutagenic?
X-rays ultraviolet rays
Which of the following are manufactured by microbial fermentation?
Yogurt, cheese, beer
In conjugation in E. coli, an Hfr cell refers to ______.
a cell in which the F plasmid has been integrated into the cell chromosome
The capsule stain shows the capsule as ____.
a clear area surrounding a cell
when preparing a wet mount specimen for viewing, what should be placed on top of the specimen?
a coverslip
The outbreak of measles within the last few years is due to
a decline in vaccination of children in the previous years.
Compared to an electron microscope, the atomic force microscope has ____.
a higher resolving power and does not require special sample preparation
An infectious agent that consists of protein and no nucleic acid is called
a prion
A prion is best described as ______.
a proteinaceous infectious agent
Which of the following is most likely to be a pure culture?
a single colony growing on a streak plate
A typical bacterium possesses ______.
a single, circular chromosome
A broad-spectrum antimicrobial is most likely effective against ______.
a wide range of both gram-positive and gram-negative bacteria
Transporter uses energy in the form of ATP or the proton motive force to move molecules against a concentration gradient.
active transport
When lactose enters an E. coli cell, an H+ enters at the same time. Based on this information, which mechanism does the cell use to transport lactose?
active transport using proton motive force
The major categories of animal viral infections are _____infections, characterized by the sudden onset of symptoms of a relatively short duration, and _____infections that can continue with or without symptoms for years.
acute; persistent
Which are the two major categories of viral infections?
acute; persistent
When antimicrobials are used in combination, and their interaction is neither antagonistic nor synergistic, the combination is said to be
additive
When antimicrobials are used in combination, and their interaction is neither antagonistic nor synergistic, the combination is said to be ______
additive
If O2 is present in an environment, it is said to be
aerobic
Some microorganisms can alter characteristics of certain surface proteins, allowing them to avoid detection by the host's immune system. This phenomenon is called ______.
antigenic variation
Chemicals used in the therapy of infectious diseases are called _____ medications.
antimicrobial
Chemotherapeutic agents that are used to treat microbial infections can be more specifically called _____ medications.
antimicrobial
Explain how drug resistance develops in bacteria and ultimately limits the usefulness of all known antimicrobials.
antimicrobials kill or inhibit sensitive organisms, providing a selective advantage to resistant strains; these strains are spread in the population
slime molds _____.
are composed of ameboid cells are important to the food chain Are terrestrial organisms ingest organic matter
It is often difficult to choose which germicide to use because often the most effective options ______.
are not the safest
Germicidal chemicals ______.
are often poorly understood with regards to mechanisms of action usually react irreversibly with proteins, DNA, cytoplasmic membranes, or viral envelopes
Many bacteria are able to recognize and destroy invading DNA. It is thought this ability evolved ______.
as defense against phages
About 75% of all known fungi are members of the phylum ____ . These include Penicillium species, morels, and truffles.
ascomycota
The majority of medically important fungi are members of what phylum?
ascomycota
Budding is a type of _______ reproduction that occurs in _______.
asexual; yeast
During the ____or maturation step in viral multiplication, capsids and genetic material are packaged into virions.
assembly
Which of the following describes the various viral parts coming together to produce virions?
assembly
A(n) ____ force microscope uses a very sharp scanning probe to produce detailed images of surfaces with a very high resolving power
atomic
rod or cylindrical
bacillus
Peptidoglycan provides strength to the cell walls of
bacteria
Penicillin interferes with the synthesis of peptidoglycan, and lysozyme degrades peptidoglycan. Based on this information, you can conclude that penicillin and lysozyme may result in bursting (lysing) of which type of cells?
bacterial
Which four of the following microbial groups are the most resistant to chemical control methods?
bacterial endospores Mycobacterium species protozoan cysts and oocysts nonenveloped viruses
Which of the following are caused by chemical mutagens?
base substitutions Frameshift mutations
Chemical mutagens can cause two types of mutations: ____substitutions and ____mutations.
base; frameshift
When bacteria or archaea are grown on agar plates or in tubes or flasks of broth, these closed systems are CALLED A ____ culture. By contrast, cells can also be grown in an open system, or a continuous culture.
batch
cell wall (peptidoglycan) synthesis
beta-lactam drugs
Bacteria and archaea typically divide by a process known as
binary fission
What term is used to describe a group of microbes co-existing in polymer-encased communities?
biofilm
an assemblage of surface-associated microbial cells that is enclosed in the extracellular polymeric substance matrix
biofilm
Many bacterial communities secrete polysaccharides and other hydrophilic polymers. This mesh-like accumulation can help protect the bacteria growing within from antibiotics or disinfectants. These communities are called
biofilms
A new field has emerged which employs the power of computers to store, retrieve, and analyze DNA sequence data called ______.
bioinformatics
In bacteria, ____refers to DNA transfer requiring cell to cell contact.
conjugation
The F or fertility plasmid contains genes that are required for bacterial ______.
conjugation
Which of the following are the three main methods of gene transfer in bacteria?
conjugation transformation transduction
A plasmid that can directs its own transfer from donor to recipient cells is called a(n) ____ plasmid.
conjugative
Enzymes that are synthesized constantly in a cell are called
constitutive
Creation of low O2 microenvironment
consumption of O2 by aerobic growth
Conjugation in bacteria requires ______.
contact between donor and recipient cell
staining of a microbial specimens affects which aspect of microscopy
contrast and resolution
The cytoplasmic membrane of prokaryotic cells plays a crucial role in transforming energy. This means that the membrane is directly involved in
converting the energy of sunlight or food into ATP
In E. coli, less than 50% of the genes are found in all strains. These conserved genes are called the ____ genome
core
The genes that are present in all strains of a given species are called the ______.
core genome
In recent years, a new field of bioinformatics has emerged, which ______.
creates the computer technology to store, retrieve, and analyze nucleotide sequence data
A surgical scalpel is rated as a ______ instrument because it penetrates skin and mucous membranes and therefore must be sterile.
critical
The ______ is the inner thick substance of a cell. It is filled with nutrients, ribosomes and enzymes.
cytoplasm
The part of the cell that is enclosed by the cell envelope is called the ____
cytoplasm
The thin delicate structure that surrounds the cytoplasm and defines the boundary of the cell is called the
cytoplasmic membrane
When an enveloped virus gains entry to an animal cell by fusion, the virus envelope fuses with the ______.
cytoplasmic membrane
Which of the following acts as a selective barrier between the interior and exterior of the cell?
cytoplasmic membrane
Which of the following separates the interior of a prokaryotic cell from its outside environment?
cytoplasmic membrane
a phospholipid bilayer embedded with proteins that surrounds the cytoplasm and defines the boundary of the cell.
cytoplasmic membrane
Previously it was thought that bacteria lacked a(n)____ a network of interior proteins that provides support and structure to the eukaryotic cell. Recently though, similar proteins have been characterized in bacteria.
cytoskeleton
What internal structure helps control cell shape and is involved in cell division?
cytoskeleton
cell membrane integrity
daptomycin
In order to detect bacteria growing in patient blood samples, clinical labs can use a fluorescent sensor to detect the slight ______ in pH that accompanies the production of carbon dioxide.
decrease
where sexual reproduction of the parasite takes place
definitive host
The most highly resistant microbial structure is the bacterial
endspore
Medications effective against HIV include post-attachment inhibitors, CCR5 antagonists, and fusion inhibitors. These three groups are collectively called ____ inhibitors.
entry
The surface layers of a prokaryotic cell are collectively referred to as the cell _______.
envelope
Which types of viruses are released by budding?
enveloped viruses
Choosing the correct antimicrobial procedure depends on many factors including ______.
environmental conditions type and number of microbes composition of item
Some secreted cells will act as __ outside of the cell and catalyze the breakdown of large macromolecules.
enzymes
The target of most antifungal drugs is ____, a sterol found in the plasma membrane of fungal but not human cells.
ergosterol
Membrane-bound organelles transform energy
eukaryotes
One or two sets of linear chromosomes confined to the nucleus
eukaryotic genomes
Dimorphic fungi are fungi that typically can ______.
exist as either a yeast or a mold
Some microorganisms live in harsh environments that kill most other organisms. The term used to describe an organism with this characteristic is
extremophiles
When integrated F plasmid DNA in an Hfr cell is excised from the chromosome, an excision error can result in the removal of chromosomal DNA along with the F plasmid DNA, creating a plasmid called ______.
f'
Transporter allows a substance to move down its concentration gradient.
facilitated diffusion
Which of the following is a type of transport mechanism rarely used by prokaryotic cells?
facilitated diffusion
What are the three categories of transport systems?
facilitated diffusion group translocation active transport
True or false: A direct cell count typically determines only the number of live cells in a sample.
false
True or false: A point mutation always leads to a shift of the reading frame from the point of mutation downstream.
false
True or false: An RNA transcript is a strand of RNA copied from an RNA template.
false
True or false: Antibiotics are completely safe to use.
false
True or false: Because helminths and protozoa were recognized to cause diseases long before the roles of bacteria and viruses were understood, much more research has gone into understanding these organisms. As a result, we have many more antiprotozoan and antihelminthic drugs available, which is why these diseases tend to get so little coverage.
false
True or false: Choosing which germicide to use is not that complicated since we only consider how effective it is against the target microbes.
false
True or false: Fungi are usually only found in harsh environments like hot springs and in the deep ocean.
false
True or false: In bacterial conjugation, all F+ donor cells are high frequency recombinant (Hfr) cells.
false
True or false: Susceptibility of a pathogen to a specific antimicrobial drug is almost always predictable.
false
True or false: There are no useful antimicrobials that inhibit nucleic acid synthesis because the processes are essentially the same in both eukaryotic and prokaryotic cells, making the drugs too toxic to humans.
false
True or false: There is a standard antimicrobial procedure available from the Centers for Disease Control and Prevention (CDC) that can be used for all different microorganisms under any condition.
false
True or false: There is no need to classify viruses because they are not living organisms.
false
True or false: Ultraviolet rays are chemical mutagens.
false
Which of the following phage types cause productive infections that do not kill the host cell?
filamentous
The straining of a fluid or air through a membrane to trap microorganisms is known as ____
filtration
_______ does not actually destroy microbes or inhibit their growth but instead removes them physically from samples.
filtration
_______ is a physical means used for destroying or removing microorganisms.
filtration
a group of medications called the ___-____ drugs are preferred for the use against species of mycobacterium, because the are the most effective as well as the least toxic
first line
nucleic acid synthesis
fluoroquinolones
Which of the following antimicrobials inhibit nucleic acid synthesis?
fluoroquinolones, rifamycins, and metronidazole
Among the most useful antibacterial medications that interfere with metabolic pathways are the ____ biosynthesis inhibitors: sulfonamides and trimethoprim.
folate
A(n) ____mutation results from an insertion or deletion of nucleotides, leading to a shift of the reading frame from the point of mutation downstream.
frameshift
addition or deletion of bases shifts the translational reading frame
frameshift mutation
Small, rigid, protein-bound compartments that provide buoyancy to some aquatic bacterial cells are called
gas vesicles
A ______ is a sequence of nucleotides that usually codes for one functional protein.
gene
Functional unit which code for gene products, mostly proteins
gene
The functional unit of a genome that codes for a product is a(n) ____
gene
Which form of transduction results from packaging errors during phage assembly?
generalized
Time it takes for a population to double
generation time
Complete set of genetic information in the cell. Bacteria have DNA one, viruses have DNA or RNA one
genome
Which of the following are found in the cell walls of fungi?
glucan; chitin
In the case of animal viruses, the molecules that viral spikes attach to on the host cell in order to gain entry are typically ______.
glycoproteins
Bacteria that have a cell wall characterized by a thin layer of peptidoglycan surrounded by an outer membrane; when gram stained, these cells are pink.
gram-negative bacteria
Bacteria that have a cell wall characterized by a thick layer of peptidoglycan; when gram stained, these cells are purple
gram-positive bacteria
The antifungal drug griseofulvin interferes with the action of tubulin, the protein that polymerizes to form microtubules and a factor necessary in nuclear division. Tubulin is found in all eukaryotic cells. How can the selective toxicity of griseofulvin be explained?
greater uptake by fungal cells
As glucose is transported into an E. coli cell, a phosphate group is added to the molecule, creating glucose-6-phosphate. Based on this information, this type of transport system is referred to as
group translocation
Which transport process chemically modifies the transported molecule as it passes into the cell?
group translocation
transporter chemically alters the substance as it is transported across the membrane
group translocation
A mycosis is caused when a fungus ______.
grows on or in the human body and causes disease
Bacterial -increase in the size of a pop. (exponential/logarithmic)
growth
factor is an organic compound, such as a vitamin or an amino acid, that a given microorganism cannot synthesize and therefore must be provided in the growth medium.
growth
What term is used to describe essential organic compounds, such as a vitamin or amino acid, that must be provided in the diet?
growth factors
bacteria that require high salt concentrations for cell growth.
halophile
The ____ are worms, a type of animal, that are divided into two groups: the roundworms (nematodes) and the flatworms
helminths
With a few exceptions, most of the antiviral drugs that interfere with nucleic acid synthesis are limited to treating infections caused by ______.
herpesviruses HPV
An organism that must consume organic matter is called a(n)
heterotroph
Which type of organism requires organic compounds for its carbon and energy needs?
heterotroph
Disinfectants that destroy all viruses and vegetative organisms but not endospores are referred to as ____-level disinfectants.
high
All of the following are required for synthesis of new virus particles in a host cell EXCEPT ______.
homologous recombination
Symptoms of acute viral diseases result from
host tissue damage host immune response
Salting and drying decrease the availability of water in food, resulting in an environment that is ______ relative to microbes, thereby preventing their growth.
hypertonic
Molds produce intertwined thread-like multicellular filaments called .
hyphae
Fungi can be found ______.
in many different types of habitat on Earth
Most antibiotics come from species of bacteria and fungi that normally live _______.
in soils
______ is the destruction of microbes by subjecting them to extremes of dry heat, reducing them to ashes.
incineration
An auxotroph can be isolated from a prototrophic parent strain by ______ selection.
indirect
____ selection is used to isolate an auxotroph from a prototrophic parent strain, because no selective medium exists to inhibit the parent.
indirect
Mutations that are caused by external influences such as radiation or chemicals are called ______ mutations.
induced
____mutations are genetic changes caused by factors from outside of the cell such as radiation or chemicals.
induced
Viruses are best described as _______.
infectious agents
Only two drugs target viral uncoating, amantadine and rimantadine, which block ____ viruses. Although both prevent or reduce the severity of the disease, their usefulness is limited, because viral strains develop resistance easily.
influenza
Flucytosine is taken up by yeast cells and then converted by yeast enzymes to a form that interferes with nucleic acid synthesis by ______.
inhibiting an enzyme required for nucleic acid synthesis
Certain bacteria are inherently resistant to the effects of some antimicrobials. Inherent resistance is called ____ ________
innate resistance
Drugs that prevent HIV from inserting the DNA copy of its genome into that of the host cell are called integrase strand transfer inhibitors (INSTIs), or____ simply inhibitors.
integrase
Eukaryotic cells can regulate the levels of mRNA by destroying specific RNA transcripts through a process known as RNA ____________, abbreviated RNAi.
interference
What is the function of RNAi?
interference with translation by targeting a specific mRNA
Tavaborole is one of the more recently developed antifungal medications. It inhibits protein synthesis by ______.
interfering with an enzyme that "charges" a tRNA molecule by attaching the correct amino acid
For Schistosoma mansoni, the causative agent of schistosomiasis, snails are considered the ______ because they house a sexually immature stage of the parasite.
intermediate host
Houses a sexually immature stage of the parasite
intermediate host
______ provides an alternative to heat for sterilization and disinfection, but the process damages some types of plastics.
irradation
The cytoplasmic membrane of prokaryotes is composed of a ___ bilayer embedded with proteins.
phospholipid
An autotrophic organism that uses light for energy and carbon dioxide as a carbon source is termed a
photoautotroph
An organism that gets its energy directly from sunlight is called a(n)
phototroph
heat treatment, filtration, irradiation
physical method of control
Heat treatment, irradiation and filtration are examples of ______ used to control microorganisms.
physical processes
Cell surface structures that allow cells to adhere to certain material; some types are involved in a mechanism of DNA transfer
pili
In a(n) ______, viral titer can be determined by counting clear zones in a monolayer of cells.
plaque assay
Extrachromosomal DNA molecule that replicates independently of the chromosome
plasmid
____ are circular pieces of bacterial DNA that do not usually encode information essential to the life of a cell.
plasmids
Typically do not encode genes essential to the life of the cell
plasmids only
A high-solute environment damages microbial cells by causing ______.
plasmolysis
If the solute concentration is higher outside the cell than inside the cell, water will diffuse out due to osmosis. This will result in
plasmolysis
no defined shape
plemorphic
cell membrane integrity
polymyxin B
Eukaryotic mRNA is first synthesized as an immature transcript called ____-____. It has to be processed significantly before it forms mature mRNA
pre; mRNA
The act of delaying spoilage is ______.
preservation
Chemicals called ____ are used to prevent the growth of undesirable organisms in foods and beverages.
preservatives
High-____ processing (HPP) is used to decrease the number of microbes in food while maintaining the color and flavor
pressure
Which of the following use moist heat to destroy microbes?
pressurized steam pasteurization boiling
Entry inhibitors are a new group of drugs effective against HIV that ______.
prevent the virus from penetrating the host cells
Antivirals that interfere with viral uncoating ______.
prevent viral replication by preventing the nucleic acid from separating from the protein coat
Integrase inhibitors offer a new option for treating HIV infections by ______.
preventing the virus from inserting the DNA copy of its genome into that of the host cell
All of the following are examples of means by which microorganisms can respond to changing environmental conditions EXCEPT ______.
production of different ribosomes
nutrient for another microbe
production of metabolic wastes by one microbe
All of the following are examples of the commercial contributions of fungi EXCEPT ______.
production of toxins which can cause certain diseases
new viral particles are produced
productive infection
Cytoplasmic membrane plays a critical role in transforming energy
prokaryote
mostly circular chromosomes
prokaryotic genomes
Errors by DNA polymerase that incorporate the wrong nucleotide into replicating DNA can be repaired quickly by which two mechanisms?
proofreading by DNA polymerase Mismatch repair
Virally encoded enzymes required for the assembly and release of viral particles are the targets of medications used to treat certain viral infections. These medications include chemicals called
protease inhibitors
High pressure (130,000 psi) is thought to kill microbes by altering their ______.
proteins cell membranes
Regardless of the pH of the external environment, microbial cells maintain a constant internal pH, typically near neutral. For example, prokaryotes that grow in alkaline conditions bring
protons into the cell
____ are defined as being unicellular heterotrophic eukaryotic organisms that are not fungi.
protozoa
None of the Archaea have peptidoglycan in their cell walls. However, some have a similar molecule called
pseudopeptidoglycan
Population of cells derived from a single cell, all cells are identical
pure culture
culture contains only ONE species of microorganisms descended from a single cell.
pure culture
Simpler to reproduce in the laboratory
pure cultures
While standard sigma factors recognize promoters for genes that need to be expressed during routine growth conditions, alternative sigma factors ______.
recognize different sets of promoters, thereby controlling expression of specific groups of genes
The stage of viral multiplication at which budding occurs is ______.
release
Suppose that the concentration of an ion is higher in the cytoplasm than in the extracellular environment. If the bacterium wants to bring in more of that ion into the cell, which description best describes this type of transport?
requires energy from the cell, moves against the concentration gradient
The pentose sugar in RNA is ____, while in DNA the pentose sugar is ____
ribose; deoxyribose
RNA contains the sugar _____, which differs from its DNA counterpart by possessing _____ oxygen atom.
ribose; one more
surface involved in protein synthesis
ribosome
The joining of amino acids to synthesize proteins is facilitated by cytoplasmic structures called
ribosomes
The process of translation requires the three major structures. What are they?
ribosomes mRNA tRNA
What are the three major structures directly involved in translation?
ribosomes, mRNA, tRNA
nucleic acid synthesis
rifamycins
Many members of the Archaea have __ - ___ , which are sheets of flat proteins and glycoprotein subunits
s layers
Cells use a process called ____ to move certain enzymes and other proteins they synthesize out of the cell.
secretion
Medically useful antimicrobial drugs exhibit ____ ____, meaning they cause greater harm to microbes than to the human host.
selective toxicity
The cytoplasmic membrane is a(n) ___ permeable barrier of the cell.
semi
Medical instruments are classified into three categories according to their risk for transmitting pathogens. These are: critical instruments, ______ instruments, and ______ instruments.
semi-critical; non-critical
The function of mRNA is to _____
serve as a template for protein synthesis
In what ways are archaea similar to bacteria?
shapes and sizes energy sources used Method of multiplication Prokaryotic cell structure
taken often, typically multiple times each day
short half-life
The transmission of information from outside a cell to the inside is known as ______.
signal transduction
Type of point mutation that does not change the amino acid sequence
silent mutation
A procedure that requires the use of a single dye to stain a specimen is called ____ staining.
simple
The main effect of low temperature storage is to ______.
slow the activity of microbes
Which environment is more dynamic and complex?
soil and its surroundings
When certain bacteria are said to have intrinsic (innate) resistance, this means they have ______.
some inherent property that makes them generally more resistant to the effect of some antimicrobial
All of the following are examples of electromagnetic radiation EXCEPT ______.
sound waves
Which form of transduction results from excision errors during the transition from a lysogenic to lytic cycle?
specialized
____ transduction is the result of excision errors made as temperate phages transition from a lysogenic to a lytic cycle.
specialized
Attachment of animal viruses to the host cell typically occurs by means of ______.
spikes
spiral
spirillum
helical
spirochete
Mutations that arise naturally during cellular metabolism, and not as a result of exposure to mutation-causing agents, are called ____ mutations.
spontaneous
Random genetic changes that result from normal cellular processes are ______.
spontaneous mutations
______ destroy all microbes, including viruses and endospores.
sterilants
Following treatment to remove all viable microorganisms, including viruses, an object is considered to be _______
sterile
removal or destruction of all microorganisms and viruses
sterilization
The function of the cell wall is to
stop the cell from bursting
are accumulations of high-molecular weight polymers synthesized from a nutrient that a cell has in relative excess.
storage granules
Protective protein coat composed of capsomeres
structure of viral capsid
Base ______ mutations occur when an incorrect nucleotide is incorporated in place of another during DNA synthesis
substitution
Ribosomes are directly involved in ______.
synthesis of proteins
Inhibit competitors
synthesis of toxic compounds
A ______ phage can either cause a lytic infection or can incorporate its DNA into the host genome as a prophage.
temperate
When selecting an appropriate chemical disinfectant, it is important to realize that the death rate is significantly influenced by ______.
temperature pH
Slime molds are ______.
terrestrial organisms
In general, fungi are _______ organisms that grow better than bacteria on ______ fruits and vegetables and on bread.
terrestrial; acidic
protein synthesis
tetracyclines
When treating an infection with a combination of antimicrobials, why might a bacteriostatic drug be antagonistic when used with a bactericidal drug?
the bactericidal drug relies on actively dividing cells to work; the bacteriostatic drug prevents cells from actively dividing
Drugs in a family called echinocandins interfere with synthesis of β-1,3 glucan. As a result, ______.
the fungal cell wall will be weakened and the cell will burst
In acute viral infections, although the infected host cells may die, the host may survive because ______.
the host's immune system may gradually eliminate the virus
What is one disadvantage of using heat treatment to sterilize plastic items?
the items may melt
Considering that all cells synthesize proteins, how is it possible to selectively target prokaryotic protein synthesis with antibacterials?
the structure of the prokaryotic 70S ribosome is sufficiently different from the eukaryotic 80S ribosomehe
The Kirby-Bauer disc diffusion test is routinely used to determine ______.
the susceptibility of a given bacterial strain to an assortment of antimicrobial drugs
Imagine you are a microbiologist trying to isolate new species of prokaryotes. You collect numerous samples and return to your lab, where you proceed to encourage any prokaryotes present to grow. Disappointingly, you are not successful. Which is the LEAST likely explanation for this outcome?
there were no prokaryotes present where you sampled
All of the following are true statements about antimicrobials EXCEPT ______.
they are completely safe to use
Which of the following statements regarding amoebae is FALSE?
they are differential by the size of their mitochondria
Compared to conventional methods, commercial modifications of antimicrobial susceptibility testing offer what advantages?
they are less labor-intensive the results can be obtained more quickly
There are a few antibacterial medications that interfere with cell membrane integrity. How do they lead to bacterial cell death?
they cause the cells to leak
Why do fungal cell walls make a good target for some antifungals?
they contain some components not produced by animal cells
Benefits of normal microbiota include all EXCEPT which of the following?
they damage host tissue, allowing our immune system to rid the body of microbes
Some arthropods and worms are included in the study of microscopic Eukarya because _____.
they play important roles in human disease They are often carried or transmitted in forms that are microscopic
Why is it so difficult to selectively target viruses with drugs?
they rely almost exclusively on the host cell's metabolic machinery for their replication, so there are few targets for selective toxicity
Why do antimicrobials that target the bacterial cell wall usually have a very high therapeutic index?
they target peptidoglycan synthesis, which is only found in bacteria, not eukaryotic cells, so they have low toxicity
What best explains why the first-line drugs are generally given in combination of two or more to patients who have active tuberculosis, caused by Mycobacterium tuberculosis?
to reduce the chance that resistant mutants will develop
A new antifungal medication, tavaborole, inhibits protein synthesis by interfering with an enzyme that "charges" a tRNA molecule by attaching the correct amino acid. It is used ______.
topically to treat nail infections
Metagenomics is the analysis of ____
total microbial genomes in an environment
Alternative sigma factors allow cells to directly control ______.
transcription
Bacteriophages play a fundamental role in a type of horizontal gene transfer called .
transduction
Information is passed from the environment into the cell by a process known as signal
transduction
The mechanism by which bacterial DNA is moved from one bacterium to another by a bacteriophage is called _____
transduction
What term is used to describe the transfer of genetic information from one bacterium to another bacterium by a bacteriophage?
transduction
_______ is the transfer of bacterial DNA from a donor to recipient via a bacteriophage.
transduction
The process of bacterial ____________ involves the uptake of "naked" DNA by competent bacterial recipient cells
transformation
Which mechanism of gene transfer involves the uptake of "naked" DNA by competent bacterial recipient cells?
transformation
In prokaryotes, genes can be transferred from a donor to a recipient via three different mechanisms: ___, ____, and _____.
transformation, transduction, conjugation
During what process is the information in mRNA used to make a protein?
translation
Mechanisms cells use to bring in nutrients and other small molecules are called
transport systems
mechanisms cells use to transport nutrients and other small molecules across the cytoplasmic membrane.
transport systems
For facilitated diffusion to occur, the cell requires
transporter proteins, but not energy
Segments of DNA that can move to new positions within the genome of a single cell are called ____
transposons
____ are DNA segments that increase the rate of mutations by inserting themselves into genes and inactivating them.
transposons
metabolic pathways (folate biosynthesis)
trimethoprim
Certain types of protozoa produce a growing feeding form called a(n) _______, and an infectious survival form called a _______.
trophozoite; cyst
Some species of microorganisms can be found in environments where no unprotected human could survive.
true
True or false: A colony is a distinct mass of microorganisms which develop from a single cell growing on a solid medium.
true
True or false: Although bacteria and archaea have the same general cell structure, they are not closely related genetically.
true
True or false: An antimicrobial medication is a chemical used to treat an infectious disease.
true
True or false: Bacterial components unique to bacteria are potential targets for antibacterial medications used to treat infectious diseases.
true
True or false: Compared to conventional methods of antimicrobial susceptibility testing, commercial modifications are less labor-intensive.
true
True or false: Compounds unique to bacteria or certain other microbial groups can be detected by "alarm systems" in the body. True false question.
true
True or false: Regulating gene expression involves controlling mRNA synthesis and rapidly destroying mRNA transcripts.
true
True or false: The risk of developing a fatal infection after surgery has substantially decreased since the late 19th century because modern hospitals now have procedures in place to avoid microbial contamination.
true
The drug griseofulvin targets cell division by interfering with the action of ______, the protein that polymerizes to form microtubules and a necessary factor in nuclear division.
tubulin
An abnormal growth of tissue resulting from a malfunction in the normally highly regulated process of cell growth is a
tumor
describes the cloudiness or haziness of a fluid.
turbidity
Commercially important contributions attributed to fungi include ______.
uses in the wine and cheese industries genetically engineered production of insulin and vaccines The synthesis of antibiotics
All of the following statements about immunofluorescence are true except one. Which?
uses the dye of methylene blue
cell wall (peptidoglycan) syntheis
vancomycin
If you want to determine the proportion of cells that have been killed by a particular antimicrobial treatment, it would be best to do which type of cell count before and after that treatment?
viable cell count
curved rod
vibrio
Antiviral drugs that interfere with nucleic acid synthesis target ______.
virally encoded enzymes that replicate viral nucleic acid
A _______ is a single virus particle.
virion
A complete viral particle, which typically consists of nucleic acid surrounded by a protein coat, is called a(n) ____ .
virion
Which of the following are non-cellular infectious agents composed of only a single-stranded RNA molecule?
viroid
is an infectious agent that lacks a capsid and consists only of RNA.
viroid
Bacteriophages that exit the host cell at the end of an infection by lysing it are called _______ phages.
virulent
Which of the following are non-cellular infectious agents?
virus, viroid's and prions
The microbial world includes three main agents that cannot reproduce independently and are thus considered non-living. These are the ____, ____, and ____.
virus, viroids, and prions
Unlike the term microorganism, the word microbe also includes
viruses
single-celled fungi
yeasts
Which of the following microscopes exposes specimens to ultraviolet light and forms an image with the light emitted at a different wavelength?
fluorescence microscope
The ____ microscope is a specially modified light microscope that uses an ultraviolet light source.
fluorescence or confocal
For the name Streptococcus pyogenes, the first part indicates the ____ and gives information about the shape of the organism
genus
What does the scientific name of an organism include?
genus and species
Differential stains include ____.
gram stain; acid fast stain
After Gram staining, Gram-positive cells are ____ and Gram-negative cells are ____.
purple; pink
Without microorganisms, substances required for human life such as O2 and organic nitrogen would
run out
There are two main types of electron microscopes. To observe the fine details of internal cell structure, you would use the ____ electron microscope.
transmission
A bright-field microscope ____.
transmits light through a specimen
True or false. We could not survive without microorganisms, but they can also be harmful
true
True or false: without microorganisms, we would run out of certain nutrients
true
Which of the following are classified as acellular infectious agents?
viruses, viroids, and prions
Unlike a stained specimen, living moving cells can be observed using a(n) ____ mount.
wet
A gram-positive bacterium had a pink color after a gram stain was done. Was there a mistake?
yes. the decolorizer was likely left on for too long
The ____ stain is the most widely used staining procedure for distinguishing different groups of bacteria.
gram
Compared to a light microscope, an electron microscope provides ____.
high magnification, and higher resolution
Why do we care about microbiology?
huge impact on human existence modern sanitation, vaccination & antimicrobial treatments
A testable explanation for an observation is called a
hypothesis
_____ killed more people in 1918-1919 than died in world wars I and II and the Korean war combined.
influenza
iodine
mordant
Compared to other range types of of plants and animals, microbes as a group are
more diverse
The Gram stain separates bacteria into two major groups called ____, based on the structure of their ____.
positive and negative; cell walls
Crystal violet
primary stain
Today, the bacteria added to some fermented milk products are advertised as ___.
probiotics
Archaea, like bacteria, are single-celled ____ that divide via the process of ____ ____
prokaryotes; binary fission
After completing the first step of gram stain, what color would gram negative be?
purple
The concept of living things arising from vital forces in non-living or decomposing materials was known as which of the following?
spontaneous generation
When observing live organisms, the specimen is prepared with a drop of liquid on which a coverslip has been placed. This is called a ____ ____.
wet mount
Fungi are a diverse group of eukaryotes. Those that are studied by microbiologists include the unicellular ____ and the multicellular filamentous ____.
yeasts; molds
E. coli is a gram-negative bacterium. you perform a gram stain on it and it appears purple. What is the best explanation?
you forgot to apply alcohol
The objective lens of a compound microscope ____.
is a series of lenses in a tube immediately above the specimen
What is the only shared feature of all microbes?
small size
Select all that apply. Why are cells sometimes difficult to see in a wet mount?
some move quickly. some are transparent
Algae and protozoa are also referred to as ____, a diverse group that falls within the domain Eukarya.
protists
Put the steps of the scientific method in order. Earliest on top.
1. make an observation about something and ask a question about the situation 2. Develop an explanation and then devise an experiment to test this explanation 3. Collect data from the experiments and draw a conclusion 4. Communicate the methods, results, and conclusions
What are present and future challenges ?
Infectious disease remains a threat, along with emerging disease.
The work of Tyndall and Ferdinand Cohn ___.
explained why some spontaneous generation investigators got different results from those of Pasteur.
A(n) ____ force microscope uses a very sharp scanning probe to produce detailed images of surfaces with a very high resolving power.
atomic
Ulcers, previously thought to be caused by stress, are often caused by
bacterial infection
safranin
counterstain
alcohol
decolorizer
In the Gram stain procedure, a gram-negative cell would look distinctly different from a Gram-positive one after the addition of ____.
decolorizing agent
An electron microscope uses a beam of electrons, which is focused by ___ lenses, to generate a magnified image on a ____ screen.
electromagnetic; fluorescent
Tyndall and Cohn's experiments in the 1870s showed the presence of a heat-resistant form of a bacteria called a(n)
endospore
Theoretically, electron microscopes have a resolving power that is about 1,000X ____ than light microscopes, because electrons have a wavelength of about 1,000X ____ than visible light.
greater; shorter
When viewed using a microscope, the object is magnified by a factor equal to the product of the magnifying powers of the ____ lens and the ____ lens.
objective; ocular
In a compound microscope, the ____ lens, or eyepiece, is the lens that is closest to the eye of the observer.
ocular
Which of the following staining procedures requires the use of only a single dye?
simple staining
