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Microbiology Exam 2

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Study guide for Microbiology I at UWF. Questions are taken directly from the sample exam
Jo O'Bar
Quiz by Jo O'Bar, updated more than 1 year ago
Jo O'Bar
Created by Jo O'Bar over 5 years ago
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Question 1

Question
Which is true about biological reduction of nitrogen gas to ammonia?
Answer
  • Can be accomplished by free-living organisms in Domains Archaea and Bacteria
  • Can be accomplished by a variety of symbioses between prokaryotes and eukaryotic macro organisms
  • Is thermodynamically exergonic but requires high input of cellular energy (ATP)
  • Is catalyzed by an enzyme that typically contains iron and molybdenum co-factors
  • All of these answers are true

Question 2

Question
The tendency of systems to go from a lower state of order to a more organized system is supported by which of the below?
Answer
  • entropy
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Chemiosmotic Theory
  • None of these answers are correct

Question 3

Question
Enzyme(s) by which bacteria assimilate gaseous molecular nitrogen is/are...
Answer
  • Nitrogenase
  • Glutamine synthetase (GS)
  • Glutamate synthase (GOGAT)
  • Glutamate degydrogenas (GDH)
  • Both Nitrogenase and GS

Question 4

Question
The Ames test...
Answer
  • determines histidine resistace of Salmonella typhimurium
  • uses Salmonella typhimurium
  • depends on reversion of histidine auxotrophs to prototrophy
  • assesses chemical mutagenicity

Question 5

Question
Bacterial cells are not diploid because...
Answer
  • they do not reproduce sexually
  • their DNA is single-stranded
  • their DNA is double-stranded
  • they use plasmids to reproduce
  • they usually have only one set of chromosomes

Question 6

Question
Strains of E. coli with an F-factor that has integrated into the chromosome are known as
Answer
  • Hfr strians
  • Super males
  • F+ strains
  • Episomes
  • All of these answers are correct

Question 7

Question
Which of these mechanism(s) do NOT protect nitrogenase from denaturation by molecular oxygen?
Answer
  • fixation of nitrogen under aerobic conditions
  • heterocysts of cyanobacteria that separate nitrogen fixation from oxygenic photosynthesis
  • uncoupling of oxidation from phosphorylation in respiratory chain (electron transport system)
  • leghemoglobin
  • all of these answers are correct

Question 8

Question
Housekeeping genes are
Answer
  • constitutively expressed
  • essential to growth and life of the cell
  • useful to determine whether a cell is active even without culturing it
  • all of these answers are correct
  • none of these answers are correct

Question 9

Question
Which of the below contributed most to our understanding of "sex" in bacteria?
Answer
  • Joshua Lederberg and Edward Tatum
  • Paul Berg
  • Myron Sasser
  • Max Delbruck and Salvador Luria
  • The Kardashians

Question 10

Question
Transfer of gnetic information between prokaryotes that requires direct physical contact between the donor and recipient cells and does NOT require a bacterial virus is called
Answer
  • transformation
  • transduction
  • Transcendental Mediation
  • conjugation
  • none of these answers are correct

Question 11

Question
Four- and five-carbon sugars and NADPH, essential for biosynthetic (anabolic) functions, are provided by which pathway?
Answer
  • oxidatie pentose phosphate
  • Entner-Doudoroff
  • Tricarboxylic acid cycle
  • Glycolysis
  • Embden-Meyerhof, Parnas

Question 12

Question
Regulation of metabolic pathways within microorganisms is controlled in which of the following ways?
Answer
  • altering activity of key enzymes
  • regulating biosyntheseis--and thus the amount--of key enzymes
  • induction and regression of genes
  • feedback inhibition of key enzymes by end products of a pathway
  • all of the above

Question 13

Question
Why did Lederberg and Tatum use multiple auxotrophic mutants, i.e., strains with deficiencies in biosynthetic capabilities in several places, in their experiment that demonstrated conjugation in bacteria?
Answer
  • Each mutation has reversion rate 10*-8 per cell per generation. Thus, 10 in a billion cells will revert to wild-type. By using 3 mutants, the likelihood of all three reverting to wild type is infinitesimally small
  • They had a lot of auxotrophs in their culture collection
  • To prove the Mobilome
  • They were sex addicts
  • none of these answers are correct

Question 14

Question
Positive control of gene transcription involves
Answer
  • a regulator protein binding to the DNA operon.
  • interaction of a regulator protein with DNA that is not a cestron
  • enhancement of transcription effieceny
  • suppression of trascription efficiency
  • All except D

Question 15

Question
Positive control of gene transcription involves
Answer
  • A regulator protein binding to the DNA operon
  • interaction of a regulator protein with DNA that is not a cistron
  • enhancement of transcription efficiency
  • suppression of trascription efficiency

Question 16

Question
Specific regulatory interaction between proteins and DNA
Answer
  • is common and occurs in all domains in life
  • is restricted to only Domain Bacteria
  • is restricted to only Domain Eukarya
  • is restricted to only Domain Archaea
  • is restricted to only the prokaryotic domains of Bacteria and Archaea

Question 17

Question
Genomes of Domain Bacteria...
Answer
  • are haploid.
  • typically consist of one chromosome.
  • are covalently closed circular DNA.
  • may be composed of single-stranded DNA.

Question 18

Question
Nonsense-supressor mutations...
Answer
  • allow a translation stop codon to be ignored.
  • require a change in tRNA specificity
  • restore in the original, wild phenotype
  • result in substitution of an amino acid into the position specified by the stop codon in the mRNA
  • All of these answers are correct

Question 19

Question
Plasmid copy number is which of the below?
Answer
  • The same as chromosomal copy number.
  • The ratio between the numbers of a specific plasmid inside a bacterial cell and the number of chromosomes.
  • The total copies of a plasmid in a single cell.
  • How efficiently a plasmid is copied during cell division.
  • The number of genes carried on each plasmid

Question 20

Question
Nitrogenase...
Answer
  • is an enzyme
  • is common in Domain Eukarya
  • may catalyze reduction of substrates other than nitrogen gas
  • is highly conserved in Domains Bacteria and Archaea

Question 21

Question
The use of terminal electron acceptors other than molecular oxygen at the end of an electron transport chain is...
Answer
  • anaerobic respiration
  • common in heterotrophic macroorganisms including humans
  • assiilatory nitrate reduction
  • aerobic respiration

Question 22

Question
Which bacteriophage is the model for specialized transduction?
Answer
  • Coliphage Lambda (a phage that attacks E. coli)
  • coliphage 42
  • T-even coliphage
  • General transducing phages
  • None of these answers are correct

Question 23

Question
The rolling circle mechanism of DNA replication is utilized...
Answer
  • during conjugative trasfer of DNA into an F- recipient
  • during replication of DNA of some viruses
  • during most replication of bacterial chromosomes
  • by Eukarya

Question 24

Question
What principal metabolic advantage does fermentation confer to the cell?
Answer
  • Produces useful metabolic byproducts such as ethanol, acetone, lactic acid
  • Generates a prodigious quantity of ATP
  • oxidizes reduced electron carriers such as NADH
  • makes alcoholic beverages and cheeses that make people happy
  • All of these answers are correct

Question 25

Question
Which of the below mapping methods will give information on the polar relationship of two genes, e.g., whether gene B is between genes A and C?
Answer
  • co-transformation
  • co-trasduction
  • interrupted conjugation
  • sequencing of DNA bases
  • All of these answers are correct

Question 26

Question
The uncoupling of oxidation from phosphorylation during trasport of electrons via an electron trasport system to a terminal electron acceptor
Answer
  • occurs in some natural systems
  • can be experimentally induced with certain chemicals
  • results in generation of no ATP
  • produces heat
  • all of these answers are correct

Question 27

Question
The capability of a bacterial strain or species to take up naked DNA is called
Answer
  • competence
  • fertility
  • promiscuity
  • trasduction
  • lysogeny

Question 28

Question
Which possible fates for DNA that has been introduced (exogenote) into a new host cell result in the MOST-stable transfer into future generations of the recipient cell?
Answer
  • Recombination with the endogenote
  • Digestion catalyzed by host enzymes
  • Formation of a partial diploid cell
  • Formation of partial diploid clone
  • All of these answers are correct

Question 29

Question
The most abundant single protein in the biosphere is
Answer
  • a key enzyme of the Calvin-Benson-Bassham cycle
  • RuBisCO
  • pyruvate dehydrogenase
  • nitrogenase

Question 30

Question
Okasaki fragments
Answer
  • are proteins
  • encode housekeeping functions for the cell
  • are delicious but expensive appetizers at Japenese restaurants
  • accommodate the fact that DNA polymerase must synthesize the complementary new strand

Question 31

Question
A metabolic pathway that fixes carbon dioxide into an organic molecule but does not support autotrophic growth is
Answer
  • the reductive pentose phosphate cycle
  • an anaplerotic reaction
  • the reverse tricarboxylic acid cycle
  • the acetyl-CoA pathway
  • all of these answers are correct

Question 32

Question
Who was curator for the genetic map of Escherichia coli for many years?
Answer
  • Martha Hershey and Alred Chase
  • Avery, ClLeod and McCarty
  • Barbara Bachman
  • Barbara McClintock
  • Britney Spears

Question 33

Question
For this course, we have adopted which terminology as our definition of a "gene?"
Answer
  • DNA polynucleotide sequence that codes for a gene product, e.g., protein, tRNA, rRNA
  • Cistron
  • any DNA in a bacterial chromosome or plasmid
  • a DNA sequence with a specific start and end

Question 34

Question
Which of the below used radioisotopes to demonstrate that the DNA and not the protein components of bacteriophages directed infection of the host cell?
Answer
  • Avery, MacLeod, and McCarty
  • Hershey and Chase
  • Griffith
  • Watson and Crick
  • Gilbert and Sanger

Question 35

Question
Auxotrophic mutant bacteria
Answer
  • have the biosynthetic capability of the "wild type" e.g. typical bacteria of that species
  • may undergo reversion to their prototrophic forms
  • are resistant to multiple antibiotics
  • are able to obtain all their caron requirement by fixing carbon dioxide

Question 36

Question
Which pathway of glucose catabolism is found only in prokaryotic microorganisms
Answer
  • Entner-Doudoroff
  • Embden-Myerhof-Parnas
  • Calvin cycle
  • Oxidative Pentose Phosphate
  • Nitrogen fixation

Question 37

Question
Who of belaw developed a "chemiosmotic" theory that provided a unified mechanism for how ATP was made during respiration and in the light reactions of photosynthesis?
Answer
  • Peter Mitchell
  • Louis Pasteur
  • Woese, Falkow, Berg
  • Singer, Nicholson
  • Embden, Meyerhof, Parnas

Question 38

Question
Small Interfering, siRNA, or "Silencer RNA" is used to
Answer
  • suppress antibiotic resistant mutants
  • suppress expression of specific genes
  • select auxotrophic mutants
  • override stop codons
  • provide a mechanism for site-specific mutagenesis

Question 39

Question
Who won the Nobel for discovering transposons
Answer
  • Barbara McClintock
  • Barbara Bachman
  • Martha Hershey and Alfred Chase
  • Avery, McLeod and McCarty
  • Batman and Robin

Question 40

Question
Which group below has a specialized cell that compartmentalizes nitrogen fixation and sequesters it from oxygenic photosynthesis
Answer
  • filimentous cyanobacteria
  • purple non-sulfer bacteria
  • single-celled cyanobacteria
  • green sulfur bacteria
  • purple sulfur bacteria

Question 41

Question
The principle that spontaneous mutations in bacteria are rare and random
Answer
  • was supported by a fluctuation analysis experiment
  • was demonstrated by Max Delbruck and Salvador Luria
  • was demonstrated by using Poisson Distribution
  • was supported by following acquistition of mutant characteristics during the growth of E. coli in the absence of selection pressures
  • All of these answers are correct

Question 42

Question
Under optimal conditions, the complete transfer of the entire chromosome during an Hfr x F- mating between two strains of E. coli takes approximately [blank_start]100[blank_end] minutes.
Answer
  • 100
  • 10
  • 200
  • 50
  • 20

Question 43

Question
Mutants of bacteria that are defectiv in biosynthetic capability relative to the wild type can be selected using which of the below?
Answer
  • The Ames test
  • The auxotrophic-mutant rejection protocol
  • The Heimlich Maneuver
  • Use of penicillin counter-selection against prototrophs
  • Replica plating

Question 44

Question
Which of the below are/were major player(s) in our understanding of biological nitrogen fixation?
Answer
  • Robert Burris
  • Harold Evans
  • Arto Virtannen
  • Carnahan and ortenson
  • All of these answers are correct

Question 45

Question
Which of the below discovered and experimentally demonstrated that a non-living "transforming" material could change an avirulent strain of a bacterium into a virulent, pathogenic microorganism?
Answer
  • Avery, MacLeod, and McCarty
  • Fred Griffith
  • Hershey and Chase
  • Watson and Crick
  • Gilbert and Sanger

Question 46

Question
Sulfanilamide...
Answer
  • is a chemotherapeutic agent
  • competes with PABA (para-aminobenzoic acid) for an active site of an enzyme
  • is an antibiotic
  • stops transcription in bacteria

Question 47

Question
To what does the term "bacteroid" refer?
Answer
  • bacterial cells within genera Rhizobium or Bradyrhizobium that are symbiotic with leguminous plants
  • a prokaryote with characteristics similar to both Bacteria and Archaea
  • a prokaryotic bacterial cell with characteristics similar to those of eukaryotic cells
  • prokaryotic symbionts that a bacterium-like bacterium found on planets other than Earth

Question 48

Question
How do bacteroids differ from the free-living bacteria?
Answer
  • They are symbiotic form of genera Rhizobium or Bradyrhizobium with luminous plants
  • They cooperate with a plant host in producing legheoglobin
  • They reduce diatomic nitrogen gas to ammonia
  • All of these answers are correct
  • None of these answers are correct

Question 49

Question
A bacterium experienceing a severe amino acid shortage
Answer
  • may exhibit Stringent Response
  • will contain elevated levels of ppGpp
  • will continue biosynthesis of amino acids
  • will have a high level of uncharged tRNA
  • will have all of the listed properties

Question 50

Question
Which pathway produces the most ATP?
Answer
  • Entner-Doudoroff
  • Embden-Meyerhof-Pamas
  • Tricarboxylic acid cycle
  • Oxidative Pentose Phosphate Pathway
  • Electron transport chains coupled to chemiosmosis

Question 51

Question
Who wrote a treatise on the "mobilome"--emphasizing horizontal gene transfer in bacteria
Answer
  • Peter Mitchell
  • Tamar Barkay
  • Louis Pasteur
  • Carl Woese and George Fox
  • Paul Berg

Question 52

Question
What is the principal Domain of biological organisms within which Operon Theory was developed?
Answer
  • E. coli
  • Fungi
  • Eukarya
  • Archaea
  • Bacteria

Question 53

Question
Which Biological Domains apply to the below...
Answer
  • Escherichia coli = Bacteria
  • Cyanobacteria = Bacteria
  • Saccharomyces cerevisiae = Eukarya
  • Cyanobacteria = Archaea

Question 54

Question
The use of nitrate as a source of nitrogen to build cells is
Answer
  • assimilatory nitrate reduction
  • reduction of nitrate to ammonia, whcih is then incorporated into amino acids
  • nitrate respiration
  • denitrification

Question 55

Question
Transposons used as mutagens
Answer
  • alkylate (e.g., methylate) nitrogen bases of DNA
  • create thymidine dimers
  • distort the DNA backbone and cause reading frameshifts
  • interupt a gene by inserting into it
  • none of these answers are correct

Question 56

Question
Which mechanism(s) may protect nitrogenase from denaturation by molecular oxygen?
Answer
  • fixation of nitrogen under aerobic conditions
  • heterocysts of cyanobacteria that separate nitrogen fixation from oxygenic photosynthesis
  • uncoupling of oxidation from posphorylation in respiratory chain (electron trasport system
  • leghemoglobin

Question 57

Question
The Calvin-Benson-Bassam cycle
Answer
  • catalyzes the oxidation of CO2
  • has metabolic intermediates in common with the oxidative pentose phosphate pathway
  • carboxylates the sugar ribulose 1.5-bisphosphate
  • is found in both eukaryotic and prokarotic domains of life

Question 58

Question
The physiological function of anaplerotic CO2 fixation pathways is
Answer
  • to reoxidize NADH
  • to support autotrophic growth
  • to replenish 4-carbon compounds such as oxaloacetate in the TCA cycle
  • to reverse the TCA cycle

Question 59

Question
Which of the below groups includes a genus name that is NOT a diazotroph?
Answer
  • Escherichia, Fungi
  • Rhizobium, Sinorhizobium
  • Clostridium, Klebsiella
  • Azotobacter, Anabaena
  • Bradyrhizobium, Spirillum

Question 60

Question
Lectins
Answer
  • are proteins with an affinity for monosaccharide residues
  • may be used for ABO-typing of blood
  • are involved in host-plant selection for nitrogen-fixing symbioses between bacteria and legumes
  • are produced by legumes
  • all of these answers are correct

Question 61

Question
The key enzyme(s) by which bacteria assimilate relatively-LOW concentrations of ammonia is/are
Answer
  • glutamine synthetase
  • glutamate synthase
  • glutamate dehudrogenase or other amino acid dehydrogenases
  • nitrogenase

Question 62

Question
Which of the below enzymes change the covalent structure of DNA?
Answer
  • DNA polymerase III
  • DNA ligase
  • DNA gyrase
  • DNA helicase

Question 63

Question
Who performed experiments using "fluctuation analysis" and Poisson distribution characterizing spontaneous mutations in bacteria?
Answer
  • Lois Pasteur
  • Max Delbruck and Salvador Luria
  • Joshua Lederberg
  • Robert Koch and Louis Pasteur
  • Griffith, Avery McLeod and McCarty

Question 64

Question
Early, seminal experiments that distinguished between enetic exchange mechanisms of bacteria that require physical contact and those that do not employed which of the below?
Answer
  • auxotrophic mutants
  • E. coli
  • U-tube with sintered glass
  • strains of bacteria with multiple biosynthetic deficiencies
  • all of these answers are correct

Question 65

Question
Catabolism of a protein bhy any organism requires which first step?
Answer
  • hydrolysis of the polypeptide to amino acids
  • deamination
  • breakdown to glucose
  • all of these answers are correct

Question 66

Question
"Positive control" regulatory mechanisms include
Answer
  • catabolite repression
  • repression/co-repression
  • inducible operons
  • attenuation

Question 67

Question
What is the utility of the Ames test?
Answer
  • Drug resistance of Salmonella typhimurium may be determined
  • Salmonella typhimurium mutation rate may be determined
  • Genes defective in histidine biosynthesis may be corrected
  • Repair of auxotrophic mutants is accomplished
  • an index of potential carcinogenicity of a chemical may be estimated

Question 68

Question
Batch-growth kinetics of E. coli grown on lactose and glucose hat become exponential pause for a second lag phase, and then proceed to a second logarithmic phase are
Answer
  • a result of a positive-control regulatory meechanism
  • a result of a microbe's "preference"in carbon source
  • a result of a mechanism in which cyclic AMP interacts with an allosteric protein
  • termed "diauxie" or diauxic growth
  • all of these answers are correct

Question 69

Question
Regulaion by attenuation requires tight coupling between transcription and translation and, therefore, occurs in
Answer
  • eukaryotes
  • prokaryotes
  • fungi and plants
  • algae
  • protozoa

Question 70

Question
The theoretical construct describing transfer of information between macromolecules within cells is known as
Answer
  • trascriptomics
  • central dogma
  • genomics
  • proteomics
  • bioinformatics

Question 71

Question
A contiguous series of genes (cistrons) under transcriptional control of a single operator siteand regulatory protein is known as
Answer
  • a regulon
  • a transcription
  • a modulon
  • a transposon
  • an operon

Question 72

Question
Regulation by attenuation occurs commonly in which kind of operons?
Answer
  • Lac and other sugar-metabolizing operons
  • nitrogen fixation operons
  • Housekeeping gene operons
  • diauxic operons
  • amino acid biosynthesis operons

Question 73

Question
Who was awarded the Nobel Prize for elucidating transcriptional regulation in bacteria?
Answer
  • Francois Jacob, Andre L'Woff, Jacques Monod
  • Max Delbruck and Salvador Luria
  • Joshuaa Lederberg
  • Robert Koch and Louis Pasteur
  • Griffith, Avery McLeod and McCarty

Question 74

Question
Which of the below regions of DNA within an operon are NOT genes/cistrons?
Answer
  • operator
  • promoter
  • regulator

Question 75

Question
Inducible operons
Answer
  • control transcription of genes with catabolic function
  • control transcription of genes with anabolic/biosynthetic function
  • control transcription of genes with "food" acquisition and digestive function

Question 76

Question
Which are cistrons within the Trp operon?
Answer
  • control transcription of genes with catabolic fuction
  • control transcription of genes with "food" acquisition and digestive function
  • TrpE, TrpD, Trp C, TrpB, TrpA
  • LacZ, LacY, LacA

Question 77

Question
Lower gastrointestinal tracts of vertebrates are anaerobic. Which metabolic pathway(s) is/are responsible for flatulence?
Answer
  • fermentation
  • oxygenic photosynthesis
  • anoxygenic photosynthesis
  • TCA cycle
  • aerobic respiration

Question 78

Question
The "chemiosmotic theory" of oxidative phosphorylation...
Answer
  • provides a unified mechanism for how ATP is made during both aerobic and anaerobic respiration relevant to ALL biological Domains
  • depens on electron transport chains imbedded in an intact plasma- (cytoplasmic) or mitochondrial-membrane
  • explains "photophosphorylation" during the light reactions of phoosynthesis
  • won the Nobel Prize for Peter Mitchell
  • all of these answers are correct

Question 79

Question
Which molecular regulatory mechanism(s) allow a bacterium to "decide" whether to use a "preferred" carbon substrate or not?
Answer
  • catabolite repression
  • repression/corepression
  • inducible operons
  • attenuation

Question 80

Question
Mutation has been defined as...
Answer
  • a stable, heritable change in the DNA sequence of bases
  • a "genetic change that breeds true"
  • changes in the phenotype of an organism

Question 81

Question
Which is the correct sequence (in direction of transcription) of genes and regulatory sites in the Lac operon?
Answer
  • I-O-P-Z-Y-A
  • I-P-Z-Y-A
  • P-O-LEADER-E-D-C-B-A
  • Z-Y-A-P-O-I
  • LEADER-E-D-C-B-A-P-O
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