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349 Cards in this Set
- Front
- Back
- 3rd side (hint)
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In microscopy, which is an advantage of using violet blue light (420 nm) rather than red light (680 nm)?
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Violet light improves resolution, The shorter the wavelength, the better the resolution
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The illuminator is
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the source of light and is unrelated to wavelength
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Diffraction
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is the scattering of light
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Refraction
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is the bending of light.
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For which experiment in the field of virology is Wendell Stanley known?
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the demonstration that viruses are filterable agents, Wendell Stanley crystallized TMV
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Which are the basic constituents of a virus?
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a nucleic acid core surrounded by a protein coat
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a unicellular core surrounded by an envelope virus consists of
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a single nucleic acid surrounded by a protein coat
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Which differential stain procedure distinguishes between two major groups of bacteria based on cell wall characteristics?
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Gram stain
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The Gram stain classifies bacteria into two groups
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gram positive and gram negative, depending on whether the bacterium retains its color.
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Different kinds of bacteria react differently to the Gram stain because
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of structural differences in their cell walls a simple stain
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The primary purpose of a simple stain is to
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highlight the entire microorganism to reveal certain cellular structures.
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endospore stain
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The purpose of this stain is merely to isolate the endospore within a cell.
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flagella staining
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The purpose of this stain is merely to isolate the flagella within a cell.
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Eubacteria, archaea, and eukarya are considered the three major domains of life. Which statement best describes their evolutionary history?
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The three groups evolved independently from a common ancestor.
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Which type of reactions in living cells are catalyzed by enzymes and result in the breaking of bonds with the concomitant release of energy?
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catabolic
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An amphibolic reaction can be either
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anabolic or catabolic
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Anabolic reactions build complex organic molecules from
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simpler ones.
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Catabolic reactions
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break down complex organic molecules into simpler ones
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Synthesis is
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the combining of atoms to make larger molecules.
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Which is characteristic of a virus?
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Viruses require a host cell for replication.
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Viruses contain either
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RNA or DNA
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Viruses do not
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alter their sizes
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Viruses are not able to
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divide independently; they must replicate within a living cell
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Viruses can only replicate within
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a living cell
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Gram negative bacteria are decolorized with alcohol and then are treated with safranin. How will the bacteria now appear?
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pink
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Gram negative bacteria stain
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pink
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Gram positive bacteria stain
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purple
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During which phase of growth are bacteria most susceptible to an antimicrobial agent?
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log
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In the death phase
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the prokaryotes die faster than new cells are formed
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In the log (exponential growth) phase
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prokaryotes are metabolically active and thus most susceptible to antimicrobial agents
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In the stationary phase
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the number of cell deaths is balanced by the number of new cells.
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Which organic compound is found only in cell walls of bacteria?
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N acetylmuramic acid
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N acetylmuramic acid is found in
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the bacterial cell wall.
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Chitin
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is found in algal cell wall
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Phospholipids are found
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in the plasma membrane.
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Cellulose is found in
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algal cell walls
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Which ingredient makes mannitol salt agar a selective medium?
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sodium chloride
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Sodium chloride is a salt that inhibits
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non Staph. aureus growth.
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Phenol is
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a disinfectant
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Retroviruses are the only animal RNA viruses that contain which enzyme?
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reverse transcriptase
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DNA polymerase
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is not specific to retroviruses
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DNA dependent RNA polymerase
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is not specific to retroviruses
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RNA dependent RNA polymerase
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is found in picornaviruses
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Reverse transcriptase
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is found in retroviruses
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Which mutation involves base substitution?
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point
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A point mutation is
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a base substitution in which one DNA base is replaced by another one
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A frameshift mutation
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results from addition or deletion of one or more bases
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A silent mutation causes
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no change in the coded product
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A spontaneous mutation occurs
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without a mutagen
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Specialized transducing bacteriophages usually transfer host cell genes found in which location?
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a specific region of the host chromosome
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In specialized transduction
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only certain bacterial genes are transferred
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How do temperatures above the maximum growth temperature for a bacterial species generally inhibit growth?
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by denaturing enzymes
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Rapid cell division is not
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a temperature dependent growth inhibitor
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Bacterial cell walls protect against
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excessive heat
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Excessive heat denatures
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protein. Enzymes are proteins.
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Which alteration is responsible for antigenic shifts in the influenza virus?
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changes in the protein composition of the spikes
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Viruses do not have
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flagella.
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Antigenic shift does not
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alter the number of spikes
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Antigenic shift refers to
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the protein composition of the H and N spikes
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Which set of characteristics is most descriptive of protozoa?
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eukaryote, unicellular, move by cilia or flagella or pseudopodia, chemoorganotrophic
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Protozoa are not
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prokaryotes or acellular
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Protozoa are
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unicellular
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For a suspension of 1000 infectious phage particles per mL, it is known that at each cycle of invasion, 80% of the particles for this strain of phage will be lytic and 20% will be lysogenic. If 0.1 mL of virus suspension is plated onto a susceptible host, what would the expected plaque forming units (pfu) count be after a 24 hour incubation?
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80 pfu because 20% of the first invasion cycle will not form plaques
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If there are 1000 particles per mL, then
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0.1 mL = 100 particles. If 80% of these particles are lytic, then 80 plaques will form. Lytic phages result from phage destroying the host bacteria in the culture medium
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What is phenotype?
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the expressed properties of an organism, such as the enzymatic functions of its proteins
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Phenotype is the actual
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expressed properties, sometimes known as the expression of genotype
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genotype
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the coded information for all the genetic or DNA properties characteristic of a particular organism
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genetic code
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the rules underlying the translation of a sequence of bases into a specific amino acid
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During the polymerase chain reaction (PCR) process, the incubation mixture is made to cycle between low and high temperatures many times. What is the purpose of the high temperature?
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to denature template DNA
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Heating converts
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the double stranded DNA to single stranded DNA.
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Cooling allows
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the primers to attach to the single strands
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Primer DNA is not
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extended during PCR
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To set up a plate count, 0.1 mL of sample is placed into 9.5 mL of sterile buffer. From this dilution, 0.5 mL is placed into 24 mL of buffer. From the second dilution 1.5 mL is placed into 98.5 mL of buffer. What is the total dilution after the second dilution is prepared?
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¼,704
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The formula for dilution 1 is
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0.1mL/0.1 + 9.5mL = 0.1/9.6
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the formula for dilution 2 is
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0.1/9.6 X 0.5/(0.5 + 24) = 0.05/235.2 or 1/4704
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Why can adenosine triphosphate (ATP) and the proton motive force be considered equivalent forms of energy currency?
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Generation of a proton motive force can be used in the synthesis of ATP.
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Generation of a proton motive force synthesizes
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ATP
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Generation of a proton motive force can ensure
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metabolization of ATP.
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Both ATP and the proton motive force are forms of
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energy used by chemoorganotrophs & chemolithotrophs
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Generation of a proton motive force does not ensure metabolization of ATP, but it does synthesize
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ATP
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Chemoorganotrophs obtain energy from
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oxidation of organic compounds
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Chemolithotrophs obtain energy from
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oxidation of inorganic compounds.
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Folic acid functions as a coenzyme for which process?
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synthesis of purines
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metabolism of pyruvic acid
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This is a function of vitamin B1 and pantothenic acid
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Which microorganism uses CO2 for a carbon source and obtains energy from the oxidation of nitrates?
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chemoautotroph
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Chemoautotrophs
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use carbon dioxide as a carbon source and inorganic nitrates as a source of energy
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Chemoheterotrophs
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use hydrogen in organic compounds for energy sources
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Photoautotrophs
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use light as a source of energy
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Photoheterotrophs
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use light as a source of energy.
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What is the difference between respiration and fermentation?
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Respiration uses O2
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Aerobic respiration uses
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molecular oxygen as an electron acceptor
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Which types of enzymes do plasmids most often encode?
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Enzymes involved in
antibiotic resistance
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Plasmids can code for
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antibiotic resistance
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In what way do the flagella of prokaryotes and eukaryotes differ?
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The flagella of prokaryotes move by rotation; those of eukaryotes have a wave or ripple action.
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How do the lytic cycle and the lysogenic cycle of bacteriophages differ?
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in their ability to exist as prophage in the host cell
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In the lytic cycle
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phage virions are released when the cell lyses.
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In the lysogenic cycle
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the phage DNA is incorporated into the host DNA as prophage.
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When a competitive inhibitor binds to a particular enzyme, how can the reaction rate be increased?
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by increasing substrate concentration
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Increasing substrate concentration increases the reaction rate because
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the enzyme has more noninhibited substrate active sites to react with
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Decreasing enzyme concentration decreases
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the amount of enzyme activity
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Increasing substrate concentration increases
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the reaction rate, because the enzyme has more noninhibited substrate active sites to react with
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Cofactors and coenzymes are part of
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the makeup of an enzyme without which the enzyme cannot function
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Increasing the competitive inhibitor will
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decrease the reaction rate.
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What is the function of a bacterial cell wall?
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to prevent the cell from swelling and rupturing
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The cell wall protects
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the cell interior
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Bacterial respiration occurs within
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the cell membrane
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Active transport and diffusion are through the
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plasma membrane
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Protein synthesis occurs
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in the cell interior.
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Which method of sterilization is most practical for a heat sensitive solution of vitamins?
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. filtration
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Autoclaving
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involves heat
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Filtration
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allows only particles smaller in size than the vitamins to be removed from a solution
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Freezing would destroy
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vitamins
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In acting to prevent cell growth, which process in bacteria does tetracycline inhibit?
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translation
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Tetracycline’s action is
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to inhibit translation (protein synthesis) in mRNA
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Which procedure most effectively destroys microbes of all types?
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autoclaving
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Autoclaving
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at 121 degrees C at 15 psi for 15 minutes kills all organisms and their endospores
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Boiling
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is not particularly effective against bacterial endospores
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Freezing
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is used to preserve microbes
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Pasteurization
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does not kill all nonpathogens.
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Which antimicrobial agent functions by inhibiting cell wall synthesis?
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vancomycin, Vancomycin inhibits cell wall synthesis.
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Chloramphenicol
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interferes with ribosomal protein synthesis
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Erythromycin
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inhibits protein synthesis
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Sulfonamides
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inhibit protein synthesis
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Which is the best sterilization method to use for a liquid bacterial culture medium to preserve heat labile components in?
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filtration
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Chlorination
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would destroy or alter the nutrient components of the medium
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Filtration
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is used to separate bacteria from a suspending liquid
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Pasteurization
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involves heat that denatures protein and would destroy the components to be preserved
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Radiation
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can destroy the components to be preserved.
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Which wavelength from within the electromagnetic spectrum contains ultraviolet rays that are used in lamps to sterilize surfaces?
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260 μm
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260
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is in the ultraviolet range.
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700
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is in the visible light range (red)
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900
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is in the infrared range
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Which substances kill microorganisms by replacing the hydrogen of the carboxyl, sulfhydryl, or amino groups?
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aldehydes
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Aldehydes form
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covalent bonds with protein functional groups
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Acids react with
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the plasma membrane (acid hydrolysis).
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Alkylation involves
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replacing protein functional groups with alkyl groups such as ethylene oxide
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Oxidizing agents
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oxidize microbial cellular components.
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Which treatment is most effective for recovering viable bacterial endospores while killing all vegetative cells?
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heating at 80° C for 15 minutes
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Vegetative cells
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are killed at temperatures above 70 degrees C, but bacterial endospores survive 100 degrees C
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Autoclaving at 15 psi and 121° C for 15 minutes
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These conditions will kill vegetative cells and bacterial endospores
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Growth of a bacterial culture is inhibited upon exposure to chemical X. After removal of chemical X, the culture begins to grow again. Based on these observations, what term can be used to describe chemical X?
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bacteriostatic
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Bacteriostatic chemicals
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inhibit bacterial growth, which usually resumes when the bacteriostatic is withdrawn
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Antiseptics
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destroy vegetative pathogens on living tissue
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Broad spectrum
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refers to antibiotics that destroy a wide range of gram positive and gram negative bacteria
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Germicides
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kill microorganisms.
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When the antimicrobial activity of drug B is compared to phenol, the results of the last dilution to inhibit the growth of Staphylococcus aureus are obtained
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1/50, phenol: 1/100.
Phenol coefficient equals the reciprocal of the last dilution to inhibit growth by drug B
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When treating a wound, which compound would be most effective to prevent infection?
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tincture of iodine
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Chlorine
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is a disinfectant and only effective against vegetative cells
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Alcohol
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should not be used as an antiseptic on a wound because it coagulates only the top layer of protein, and bacteria can grow below that layer
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Iodine tincture
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is one of the most effective antiseptics against all bacteria, many endospores, and many viruses
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Formaldehyde
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is a carcinogen and too harsh to be used on living tissue.
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Which antimicrobial agent has a mode of action most like that of vancomycin?
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cephalothin
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Cephalothin and vancomycin both
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inhibit cell wall synthesis
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Erythromycin
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inhibits protein synthesis, while vancomycin inhibits cell wall synthesis
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Neomycin
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inhibits protein synthesis, while vancomycin inhibits cell wall synthesis
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Rifampin
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inhibits mRNA synthesis, while vancomycin inhibits cell wall synthesis.
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Which agent inhibits the replication of bacterial DNA by inducing the formation of thymine dimers?
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ultraviolet light
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Gamma radiation
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causes DNA to produce mutations
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Ethylene oxide
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denatures protein
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Ultraviolet nonionizing radiation damages
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DNA by forming thymine dimer when adjacent thymine bases form bonds together
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Nitrous acid
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is a mutagen that reacts with the adenine of DNA.
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How is the commercial sterilization of plastic apparatus achieved?
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by using ethylene oxide
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Chlorine
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is a disinfectant and kills only vegetative pathogens
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Alcohols kills fungi and bacteria but not
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endospores
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Ethylene oxide sterilizes, in that it kills all
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microbes and endospores
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Hydrogen peroxide is
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an antiseptic for killing vegetative pathogens on living tissue.
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How does the addition of sugar help to preserve foods such as jams and jellies?
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Water becomes unavailable to the spoilage organisms because it is bound by the sugar.
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Sugar does not destroy
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enzymes
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Pickling depends on
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acid and salt, rather than sugar, for its preservative qualities
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Sugar induces
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plasmolyzation of bacteria
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Sugar does not form
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a physical barrier
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Which best describes oil degrading bacteria, such as those used to clean up oil spills?
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heterotrophs that oxidize the oil as a source of carbon and energy
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Autotrophs
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use carbon dioxide as their primary source of carbon
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Heterotrophs use _______ as their source of energy
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organic carbon
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Lithotrophs are
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autotrophs
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Methanogens are
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archaea, not bacteria. They produce methane.
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In which environment is denitrification most likely to occur?
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fertilized, waterlogged garden soil
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Denitrification occurs where there is
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little oxygen.
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Which process is part of the primary treatment of sewage?
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sedimentation
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Trickling filtration is part of
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the secondary treatment
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Aeration is part of
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the secondary treatment
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Anaerobic digestion is the method of
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sludge digestion.
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Which process occurs when starch from grain is converted to glucose and maltose in the production of some alcoholic beverages?
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malting
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Malting
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is the process of yeast fermenting glucose and maltose to make ethanol
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Distillation
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is a separation process and does not produce alcohol
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What increases the rate of bioremediation of an oil spill?
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addition of phosphate and nitrogen
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Oxygen is added to enhance
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bioremediation
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Bioremediation in oil spills is enhanced by
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providing nitrogen and phosphate to the bioremediation microbes
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Decreased crop yields in soils may be traced to an increase in which process?
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denitrification
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Ammonification enables
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plant and bacterial amino acid synthesis
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Denitrification
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converts nitrates to nitrogen gas, depriving crops of nitrogen
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Nitrification
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is production of nitrites from ammonia, leading to nitrate production for protein synthesis
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Nitrogen fixation
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converts nitrogen gas to ammonia to start the nitrogen cycle.
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Transgenic animals
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can be used to produce human substances that require posttranslational modifications for their functions.
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It is not easier to collect and process transgenic products from
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animals
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Which is an example of a bacterially synthesized secondary metabolite?
|
penicillin
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Ethanol is a
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primary metabolite
|
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Penicillin
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is a bacterially synthesized secondary metabolite
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Phenylalanine
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is an essential amino acid
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Tryptophan
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is an essential amino acid.
|
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How are thermoduric bacteria, found in pasteurized milk, best defined?
|
as bacteria able to withstand, but now grow at, pasteurization temperatures
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Thermoduric bacteria can
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withstand pasteurization temperatures, but they cannot grow at these temperatures
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Thermoduric bacteria can be found in pasteurized milk; however, they are not
|
necessarily pathogenic.
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What is the most effective means of stopping the spread of dengue fever?
|
mosquito control
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Dengue fever is
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viral, not bacterial.
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Which gram negative rod occupies the human stomach lining and is implicated in the formation of peptic ulcers?
|
Helicobacter pylori
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Helicobacter pylori
|
is a gram negative epsilon protobacteria that causes peptic ulcers.
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Which is the easiest and most useful technique for controlling nosocomial infections?
|
hand washing
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Which is characteristic of the transmission of HIV from a mother who is infected to her child?
|
Transmission to the child cannot be confirmed by the IgG antibodies to HIV in the newborn’s blood.
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HIV transmission to newborns is detected through PCR, because
|
production of IgG antibodies is delayed
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Antigenic drift and antigenic shift are important factors in the epidemiology of which condition?
|
influenza
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|
|
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Influenza’s antigenic shift is due to
|
major alterations in the H and N spikes on the viral lipid layer. Its antigenic drift is due to minor annual variations of the viral antigenic makeup
|
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Which group of bacteria most often causes nosocomial disease?
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opportunistic bacteria that take advantage of compromised hosts
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Bacteria causing nosocomial infections are
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opportunistic, in that they cause pathology in an immunocompromised or weakened host, such as a patient who is hospitalized
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Which respiratory tract infection is transmitted by aerosolized water sources and not by person
|
to
|
person contact?
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Diphtheria is
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airborne
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Rhinovirus (the common cold) is
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airborne and transmitted by personal contact
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Legionnaires’ disease is
|
waterborne
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Mycoplasma pneumonia
|
is not waterborne.
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Which strains of Corynebacterium diphtheriae synthesize diphtheria toxin?
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strains lysogenic for corynephage
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The diphtheria toxin is produced when
|
the bacteria are infected by lysogenic phage carrying the tox gene.
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Which pairing of bacterial disease with transmission mechanism is correct?
|
bubonic plague by flea bite
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shock syndrome is
|
staphylococcal, and is associated primarily with tampon use.
|
|
|
|
A cat scratch can cause disease if
|
Bartonella henselae is present in the cat’s saliva Tularemia
|
can be acquired by inhaling, by ingesting, or by direct skin contact through a bite or break
|
|
|
The disease associated with nonsterile conditions during childbirth is
|
puerperal fever
|
|
|
|
Typhus is transmitted by
|
rubbing louse feces into the bite of a louse.
|
|
|
|
Yellow fever is transmitted by
|
mosquito bite
|
|
|
|
Plague is caused by
|
the bite of a flea that is infected with Yersinia pestis.
|
|
|
|
Which viral agent most frequently causes cold sores and fever blisters?
|
herpes simplex type 1 virus
|
|
|
|
Papillomavirus causes
|
warts
|
|
|
|
Varicella zoster causes
|
chickenpox
|
|
|
|
Herpes simplex1
|
causes cold sores
|
|
|
|
Herpes simplex 2
|
causes genital herpes lesions.
|
|
|
|
Which disease depends primarily on the release of degradative enzymes to cause the symptoms of the disease?
|
Clostridium perfringens
|
|
|
|
Clostridium botulinum
|
causes neurological symptoms
|
|
|
|
Clostridium perfringens
|
produces enzymes that degrade protein, releasing carbon dioxide and leading to gas gangrene
|
|
|
|
The Salmonella family (Salmonella enteriditis) causes
|
gastrointestinal disturbances such as nausea and diarrhea through lysis of cell membranes, not enzyme production
|
|
|
|
Which circumstance would place health care workers at greatest risk for HIV exposure and infection, when caring for patients with AIDS?
|
gives the patient injections
|
|
|
|
Biology of Infectious Disease
What outcome is possible when a case of streptococcal pharyngitis is insufficiently treated?
|
The individual may develop heart and joint problems due to an interaction between the Streptococcus and the immune system.
|
|
|
|
Scalded skin syndrome
|
is due to Staphylococcus infection
|
|
|
|
Heart and joint problems result from
|
Streptococcus pyogenes infection
|
|
|
|
Why are recurrences of malaria years after a primary infection quite common?
|
Some sporozoites can survive in the liver and release merozoites much later to reinitiate the disease.
|
|
|
|
Plasmodium has developed resistance to
|
primaquine, chloroquine, & quinine |
|
|
|
Which statement best explains why Neisseria gonorrhoeae, the causative agent of gonorrhea, can cause cervical infections in females and eye infections in newborns?
|
The same cell types are found in both locations
|
|
|
|
N. gonorrhoeae attaches to
|
columnar epithelial cells of the cervix and eyes
|
|
|
|
Which statement best describes gummas?
|
painful tumors associated with syphilis
|
|
|
|
Gummas are lesions caused by
|
T. pallidum, the causative organism for syphilis.
|
|
|
|
Which gastrointestinal disease is associated with campers drinking untreated water?
|
giardiasis
|
|
|
|
Giardia cysts are excreted by
|
beavers and pass into stream water and then to humans through ingestion
|
|
|
|
Salmonella
|
is not waterborne
|
|
|
|
Cholera
|
is not particularly associated with campers
|
|
|
|
Ameobic dysentery
|
is not particularly associated with campers.
|
|
|
|
An individual with food intoxication exhibits double vision, difficulty in swallowing, dizziness, and muscle paralysis. Which organism caused this condition?
|
Clostridium
|
|
|
|
Clostridium
|
is a neurotoxin and can cause double vision as well as the other symptoms.
|
|
|
|
Which type of organism is the causative agent of ringworm?
|
fungal
|
|
|
|
Ringworm is caused by
|
the fungus tinea
|
|
|
|
Which carrier is considered to be the definitive host for Toxoplasma gondii?
|
cats
|
|
|
|
Cats are essential in the life cycle of
|
T. gondii
|
|
|
|
Toxic shock syndrome results from a host response to a toxin produced by which class of disease?
|
bacterial
|
|
|
|
Toxic shock syndrome results from
|
staphylococcal infection
|
|
|
|
Which is an example of a nosocomial infection?
|
HIV positive seroconversion months after surgery that involved a blood transfusion
|
|
|
|
Which urogenital disease is difficult to cure because the causative organism remains latent inside the host’s cells?
|
genital herpes
|
|
|
|
Genital herpes (HSV 2) has a
|
lifelong dormancy in the nerve cells. Antiviral drugs alleviate symptoms and decrease the number of recurrences
|
|
|
|
Syphilis can be cured by
|
penicillin, doxycycline, and tetracycline
|
|
|
|
Trichomoniasis
|
is a protozoan infection curable with metronidazole.
|
|
|
|
is an obligate intracellular parasite that is a common agent of sexually transmitted infections (STIs)?
|
Chlamydia trachomatis
|
|
|
|
Chlamydia trachomatis is an
|
obligate intracellular planctomycete
|
|
|
|
Escherichia coli is
|
not an obligate intracellular organism
|
|
|
|
Neisseria gonorrhoeae is
|
not an obligate intracellular organism
|
|
|
|
Treponema pallidum is
|
not an obligate intracellular organism.
|
|
|
|
What is used to block the synthesis of DNA in the AIDS virus?
|
zidovudine
|
|
|
|
Alpha interferon reacts with
|
plasma or nuclear membranes
|
|
|
|
Protease inhibitors inhibit
|
proteolytic enzymes
|
|
|
|
Rifamycin inhibits
|
bacterial RNA synthesis
|
|
|
|
Zidovudine blocks
|
DNA synthesis in the AIDS virus.
|
|
|
|
An infection of the oral cavity by Candida albicans can develop in patients receiving long term antibiotic treatment. Which concept best describes the relationship between Candida albicans and the patient?
|
opportunism
|
|
|
|
Commensalism
|
is a type of symbiosis in which one organism is benefitted and the other organism is unaffected
|
|
|
|
Mutualism
|
is a type of symbiosis in which both organisms are benefitted
|
|
|
|
Opportunism occurs when
|
a type of infection in which an organism that is normally nonpathogenic becomes pathogenic in a weakened host
|
|
|
|
Parasitism is a type of
|
symbiosis in which one organism is benefitted at the expense of the host.
|
|
|
|
Which method is used to test for antibodies against the human immunodeficiency virus (HIV)?
|
enzyme linked immunosorbent assay
|
|
|
|
ELISA screens for
|
anti HIV antibodies
|
|
|
|
Hemagglutination inhibition tests for
|
infections by viruses that agglutinate red blood cells
|
|
|
|
Complement fixation is used to test for
|
syphilis.
|
|
|
|
Which is a natural host defense against bacterial pathogens?
|
lysozyme in tears and saliva
|
|
|
|
Lysozymes in tears and saliva break down
|
bacterial cell walls
|
|
|
|
Large numbers of which cell type in the blood or at the site of inflammation indicates an active infection?
|
polymorphonuclear leukocytes
|
|
|
|
Polymorphonuclear leukocytes migrate to
|
the site of inflammation
|
|
|
|
T lymphocytes are part of
|
the cell mediated immune response, but they are not the best indicator of active infection
|
|
|
|
Macrophages migrate
|
to the site of inflammation after the PMNs
|
|
|
|
Monocytes migrate to the site of inflammation
|
after the PMNs.
|
|
|
|
A gram positive bacterium is exposed to the enzyme lysozyme. What will be the result of this exposure?
|
mucopeptide layer of the cell wall, causing the cell to lyse
|
|
|
|
Lysozyme catalyzes the hydrolysis of the disaccharide backbone of the cell walls of
|
gram positive bacteria.
|
|
|
|
Which disease stage occurs after a pathogen enters the host, but before any signs or symptoms appear?
|
. incubation
|
|
|
|
Convalescence
|
is the period after an illness when the patient regains strength and returns to the predisease state
|
|
|
|
Incubation
|
is the period between infection and manifestation of signs and symptoms
|
|
|
|
Prodromal
|
is the period after incubation when, in some diseases, mild symptoms become manifest
|
|
|
|
Invasion
|
is the entry of a microorganism into a host.
|
|
|
|
What antigens will elicit an antibody response in human beings?
|
numerous different antigenic determinants
|
|
|
|
Antigenic determinants can be
|
proteins or large polysaccharides
|
|
|
|
How are diseases such as AIDS, tuberculosis, and malaria characterized?
|
infectious, opportunistic, epidemic
|
|
|
|
AIDS, TB, and malaria are
|
infectious (invading or colonizing), opportunistic (pathogenic in a weakened host), and epidemic (many people within a given area become infected)
|
|
|
|
Malaria is not
|
pandemic (worldwide)
|
|
|
|
Which circulating white blood cells are most actively phagocytic?
|
neutrophils
|
|
|
|
Basophils release
|
histamines and are not phagocytic
|
|
|
|
Eosinophils are only
|
slightly phagocytic
|
|
|
|
Lymphocytes produce
|
antibodies and are not phagocytic
|
|
|
|
Neutrophils are
|
highly phagocytic
|
|
|
|
What is the result of releasing lipopolysaccharide (LPS) from the cell wall of gram negative bacteria into the bloodstream of a human?
|
fever, pain, and death due to endotoxic shock
|
|
|
|
These are the symptoms of
|
endotoxic shock syndrome
|
|
|
|
Enterotoxicity is due to the release of enterotoxins, not to release of LPS Neurotoxicity is due to
|
the release of a neurotoxin, not to release of LPS
|
|
|
|
Cytotoxicity is due to
|
an exotoxin, not to release of LPS.
|
|
|
|
Which enzyme produced by Streptococci destroys clots and allows the organisms to spread?
|
. streptokinase
|
|
|
|
Coagulase
|
clots blood fibrin. It is produced by Staphylococcus aureus, not by Streptococci
|
|
|
|
Collagenase facilitates
|
gas gangrene by breaking down muscle collagen
|
|
|
|
Hyaluronidase
|
breaks down hyaluronic acid in the connective tissue
|
|
|
|
Streptokinase
|
dissolves clots, allowing bacteria to pass into the blood.
|
|
|
|
Naturally acquired, passive immunity results from antibodies crossing the placenta Naturally acquired, active immunity results from
|
antigens naturally entering the body
|
|
|
|
Artificially acquired, passive immunity results when
|
preformed antibodies are injected into the body
|
|
|
|
Artificially acquired, active immunity results when
|
antigens are introduced into the body in the form of a vaccine.
|
|
|
|
Which condition is an example of an atopic immune disease?
|
hay fever
|
|
|
|
Lupus
|
is systemic
|
|
|
|
Atopic means
|
chronic and local.
|
|
|
|
The atopic immune diseases include
|
hay fever, asthma, and eczema
|
|
|
|
Rheumatoid arthritis is a
|
systemic autoimmune disease.
|
|
|
|
What do persons with type O blood have?
|
both anti A and anti B antibodies circulating in their plasma
|
|
|
|
There are no type ____ antigens
|
O
|
|
|
|
A and B antigens are on the
|
RBCs of type AB blood
|
|
|
|
Type AB blood lacks
|
anti A and anti B antibodies. There are no anti ABO antibodies
|
|
|
|
Type O blood lacks
|
A antigens and B antigens. Thus it has anti A and anti B antibodies.
|
|
|
|
Which rationale explains the most probable reason why most vaccinations are not given at birth?
|
Maternal antibodies from placental transfer and/or colostrum may bind the antigens in the vaccine.
|
|
|
|
Maternal antibodies that cross the placenta or antibodies from the colostrum can
|
inactivate the antigens of the vaccine
|
|
|
|
Newborns can be immunized against hepatitis B if
|
the mother is HBV positive.
|
|
|
|
Which antibody isotype containing a secretory component can be transported across membranes?
|
IgA
|
|
|
|
IgA contains a
|
secretory component bound to the monomers by a J chain, and can cross membranes
|
|
|
|
IgE contains
|
no secretory component, and attaches to mast cells
|
|
|
|
IgG contains
|
no secretory component, and passes through blood vessels and the placenta
|
|
|
|
IgM contains
|
no secretory component. Its 5 monomers are bound by a J chain and it does not pass through membranes.
|
|
|
|
A person with agammaglobulinemia could potentially have which condition?
|
contact dermatitis
|
|
|
|
Anaphylactic hypersensitivity occurs in individuals with
|
extreme type I (IgE mediated) reactions. A person with agammaglobulinemia will not produce IgE
|
|
|
|
Atopy is
|
chronic and local, mediated by IgE
|
|
|
|
In the absence of all immunoglobulins
|
contact dermatitis (a type IV or T cell mediated reaction) can still occur
|
|
|
|
Transfusion reaction involves
|
IgG and IgM.
|
|
|
|
Which criterion indicates a concern for hemolytic disease in a newborn?
|
the father and fetus are Rh+ and the mother is Rh neg
. If the fetal Rh positive blood enters the Rh negative maternal circulation, the mother will mount an immune response against the foreign Rh positive antigens of the fetal blood.
|
|
|
|
If both parents are Rh negative
|
they are homozygous and neither can pass to the fetus Rh antigens that would sensitize the mother
|
|
|
|
Rh negative blood has no
|
antigens with which to sensitize the mother
|
|
|
|
Which mechanism of hypersensitivity is experienced during anaphylaxis?
|
IgE interacts with mast cells and basophils, resulting in vasodilation and bronchoconstriction.
|
|
|
|
Which is a nonspecific defense mechanism that is present in some mucous membranes?
|
removal of microbes by ciliated cells
, The ciliary escalator carries dust and microbes caught in mucus toward the throat
|
|
|
|
The spleen filters
|
red blood cells
|
|
