Microbiology Exam 2

You set up a third test tube containing 8 mL water, 1 mL PTU, 1 mL potato juice, and 3 mL catechol. If this third test tube turned brown, this would suggest which of the following?

PTU is a competitive inhibitor of catechol oxidase

Label the figure to show your understanding of cell function. Not all labels are used.

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Label the graphs demonstrating the effect of environmental factors on enzyme activity.

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Label the intermediates and products of glycolysis. Not all labels are used.

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Label the overview of the central metabolic pathways and their associated components. Not all labels are used.

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Match the following key terms to refresh yourself with the concepts of Chapter 8: Bacterial Genetics.

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Match the mutation with the correct name. Not all labels are used.

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Organize the steps that are involved in the mechanism of RNA interference (RNAi).

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Place the correct sequence of experiments in order to better understand the Griffith Experiment for Transformation.

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Place the descriptions into the correct domain column.

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Place the following events in the process of transduction in the correct order. Not all labels are used.

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Place the following events in the process of virus replication and the generation of a transducing particle in the correct order.

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Place the labels into the correct columns for moist heat and dry heat:

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Place the labels to show the relationships between catabolic reactions and anabolic reactions.

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Place the steps in the translation process in the correct order on the diagram.

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Consider the figure below and check all the TRUE statements.

*picture -A vancomycin-resistant S. aureus mutant is created. -In order for S. aureus to become vancomycin-resistant, conjugation must have occurred between the E. faecalis and the S. aureus. -Either the S. aureus or the E. faecalis must have a conjugative plasmid.

Which is the correct labeling of the mutations in the figure?

*picture 1: silent; 2: nonsense; 3: missense

What would be the consequence of a transposon inserting into the site shown by the red arrow?

*picture The bacterium would likely become sensitive to tetracycline.

Consider the figure below, showing repair of DNA. Which statement about the process is TRUE?

*picture The enzymes involved in the process are DNA degrading enzyme, DNA polymerase and DNA ligase.

Consider the figure. If the purple liquid was distilled water, the researcher would expect the number of colonies on plate A to be _____ as the number on plate B

*picture more or less the same

This figure is displaying the same information twice—a D value related to logarithmic killing of microbes. Place the tags on the correct areas to identify a) what the D value is and b) what it means. Not all labels are used.

+

Label the reactants and intermediates of the transition step and the TCA cycle. Not all labels are used.

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1. What organism was the cause of the outbreak at the Seneca Lake Sprayground? 2. What type of organism caused the outbreak at Seneca Lake Sprayground? 3. True or false: Chlorine treatment is effective in removing Cryptosporidium from water. 4. Cryptosporidium infection results in diarrhea that is self-limiting in healthy people, but in ______ patients, it can produce dehydration through severe diarrhea and can be life-threatening.

-Cryptosporidium -Protozoan -false -infants, elderly, or immunocompromised

Which of the following are antibiotics or types of antibiotics mentioned in the study?

-Colistin -Penicillin -Carbapenem -Polymyxin E

Please select the FALSE statement regarding taxonomic hierarchy

A domain is a collection of similar kingdoms; there are three domains: Bacteria, Archaea, and Animalia.

Please select the INCORRECT statement regarding mutation.

A missense mutation is also called a synonymous mutation, meaning no change in the amino acid encoded.

Which of the following statements regarding mutations is TRUE?

A prototroph can grow on glucose-salts media.

You set up a third test tube containing 8 mL water, 1 mL PTU, 1 mL potato juice, and 3 mL catechol. If this third test tube showed no change, this would suggest which of the following?

PTU is a non-competitive inhibitor of catechol oxidase.

The results of your test tubes suggest which of the following?

PTU is an inhibitor of catechol oxidase.

Which of the following is/are not (a) sterilization method(s)?

Pasteurization

What do you think the researchers included as part of their enrichment culture in order to isolate Sulfurospirillum halorespirans?

Perchloroethylene Lactate Soil sample from a PCE-contaminated site

Greenlake is a small lake in Seattle, WA that sometimes experiences blooms of cyanobacteria, photosynthetic nitrogen-fixing bacteria that typically grow as filaments. These blooms are especially likely to occur during warm summer weather and result in the production of large quantities of biomass that then dies off and decomposes, leading to unpleasant odors. In addition to the aesthetic problems, some strains make toxins that can be dangerous to ingest, leading to the closing of the lake. Treatment of the water with alum (aluminum sulfate) to remove phosphorus from the water has helped to limit growth of cyanobacteria. How would you classify the cyanobacteria from Greenlake in terms of their carbon and energy sources?

Photoautotroph

You inoculate fern spores onto the surface of a growth medium in Petri dishes and wait for them to develop into gametophytes, a stage in the life cycle of a fern. The medium contains sources of nitrogen, phosphate, and a number of other macro- and micro-nutrients, but no carbon. After a few weeks, you see a contaminant growing on your plates. Assuming the organism is not digesting the agar itself, which of the following is most likely your contaminant?

Photoautotrophic species of bacteria, archaea, or protists

Which of the following represents the correct sequence of events during photosynthesis?

Photosystem II (ATP production) --> Photosystem I (NADPH production)

Pasteur set up the following experiment: he prepared a solution of sugar, ammonia, mineral salts, and trace elements, and added some yeast cells to it. He then measured the number of yeast cells as well as the sugar and alcohol levels over time. He noted that as the yeast cells multiplied, sugar levels decreased and alcohol levels increased, suggesting that the yeast cells were converting the sugar to alcohol. What do think would be an appropriate control for this experiment?

Preparing a solution of sugar, ammonia, mineral salts, and trace elements, but not adding any yeast cells to the solution.

Which of the following types of repair does not require the standard DNA polymerase with proofreading capability?

SOS repair

Thymine dimers are removed by

SOS repair, photoreactivation repair, AND excision repair

In the figure, what are the correct terms for the regions labeled "A" and "B"?

A: Promoter; B: Terminator

Which pairing is incorrect?

A:G

On which of the following DNA strands will UV light have the most effect?

ACTTGCCTTAC

The Calvin Cycle uses ______ and ______, produced in the light reactions of photosynthesis, to drive the fixation of carbon dioxide.

ATP and NADPH

Consider how an aerobically respiring bacterial cell uses glycolysis, the TCA cycle, and oxidative phosphorylation to break apart and oxidize glucose. What are the three main benefits these central metabolic pathways yield to the cell?

ATP, reduced electron carriers, and precursor metabolites.

If the transcript shown here is translated, what is the codon that corresponds to the second amino acid in the resulting protein?

AUC

When outbreaks occur, the attack rate can be calculated—this describes the proportion (percentage) of people becoming ill in a population after exposure to an infectious agent. Attack rate is calculated as the total number of cases divided by the total exposed population. What is the attack rate in this case?

About 1.4%

Which staining procedure would be done to identify Mycobacterium abscessus?

Acid fast stain.

Consider the biochemical pathway: A → B → C Enzyme 1 catalyzes A → B Enzyme 2 catalyzes B → C If enzyme 2 is inactive, which of the following compounds will accumulate?

B only

You tell Jasmine that there are various ways that she can in fact sterilize the knife she plans to use. Which of the following is unlikely to be available to Jasmine for sterilizing her knife in her home?

Irradiating the knife with gamma rays

Which of the following phenotypic methods is used to help identify prokaryotes by analyzing antibody reactivity?

Serological testing

An open reading frame or a possible protein-encoding region of prokaryotic DNA is

a region of DNA that begins with a start codon (ATG) and ends with a stop codon.

A regulatory protein binds to the operator in a strand of DNA, blocking transcription. The protein is

a repressor

Very often clinically relevant information may be obtained by examining

a wet mount AND the size and shape of the organism

In conjugation, transformation, or transduction, the recipient bacteria is most likely to accept donor DNA

from the same species of bacteria

The proofreading function of DNA polymerase reduces the error rate from about one in a million base pairs to about one in a ______ base pairs

hundred million

The addition of radiolabeled probe molecules to the DNA fragments results in ______.

hybridization

Chemical mutagens often act by altering the

hydrogen bonding properties of the nucleobase

The two strands of DNA are bonded to one another by

hydrogen bonds

These dimers weaken ______ between bases.

hydrogen bonds

DNA probes have been very useful in

identifying organisms in pure culture

Oxidation of proteins is achieved most readily

in a hot air oven

DNA repair mechanisms occur

in both eukaryotes and prokaryotes

T/F: F plasmids and oftentimes R plasmids are both able to code for production of a pilus.

true

T/F: Generally, heavy metals, except silver, have been proven to be too toxic for use on human tissue and are no longer used medically

true

T/F: Glyceraldehyde-3-phosphate and 3-phosphoglycerate are three-carbon molecules produced during the Calvin Cycle.

true

T/F: Horizontal DNA transfer may make it more difficult to construct phylogenetic trees.

true

T/F: In a biochemical pathway, the product of the first reaction becomes the substrate in the second reaction.

true

T/F: Mutations are likely to persist after SOS repair, but not after light-induced or excision repair

true

T/F: Organic acids, such as benzoic acid, are often added to foods to prevent microbial growth.

true

T/F: Plasmids often carry the information for antibiotic resistance.

true

T/F: Plastoquinone is the primary electron acceptor for electrons leaving photosystem II.

true

T/F: Protons used to set up the proton motive force are generated as macromolecules like glucose are oxidized in the cell.

true

T/F: Size and shape may allow one to differentiate between a bacterium, fungus, and protozoan.

true

T/F: The Calvin Cycle fixes carbon dioxide into organic molecules.

true

T/F: The G + C content can be measured by determining the temperature at which double-stranded DNA denatures.

true

T/F: The anticodon determines which amino acid is linked to its tRNA.

true

T/F: The energy captured in the phosphorylation of ADP to ATP comes from the proton motive force created in respiration.

true

T/F: The genetic code is nearly universal.

true

T/F: The government agencies that regulate germicidal chemicals are the Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA).

true

T/F: The minus strand of DNA serves as the template for RNA production

true

T/F: The more bacteria one starts with, the longer it will take to kill them all

true

T/F: The more bacteria present on or in something, the longer it takes to kill them all.

true

T/F: Transposons can potentially inactivate bacterial genes by "jumping" into them.

true

T/F: Transposons may leave a cell by incorporating themselves into a plasmid

true

T/F: Upon heat treatment, bacteria die at a constant proportion

true

T/F: Whenever a molecule is oxidized, another molecule must be reduced.

true

Indirect selection

is necessary to isolate auxotrophic mutants

The E-site

is responsible for the release of the tRNA

The P-site

is the peptidyl site on the ribosome

Signal transduction

is the relay of information about conditions outside a cell to inside the cell

Pasteurization

is the use of heat to reduce numbers of pathogenic /spoilage bacteria in a food item to a safe level

Phage typing

is used to distinguish bacterial strains

Replica plating

is useful for identifying auxotrophs AND uses media on which the mutant will not grow but the parental cell type will

Glutaraldehyde

is very good for use on heat-sensitive medical items

Ethylene oxide is gas that

is very useful for sterilizing heat- or moisture-sensitive items

The S. aureus methicillin resistance gene occurred on ______, while the E. faecalis vancomycin resistance gene occurred on ______.

plasmid A; a transposon

The lac operon

positively regulated by the presence of lactose

Two isolates with identical RFLPs are considered

possibly the same strain

RNA is characterized by which one of the following features?

Ribose

T/F: Based on DNA hybridization, humans and chimpanzees are the same species.

true

T/F: DNA polymerase is able to proofread the DNA sequence

true

T/F: Each gene mutates at a characteristic frequency.

true

Transposons can cause mutations by

"jumping" into a gene and disrupting its function

The anticodon determines which amino acid is linked to its tRNA.

(AT GC) ZZZZZZZZZZZZ

Categorize the descriptions of mRNA as being true for either prokaryotes or eukaryotes.

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Classify the given microbes and infectious agents into "sensitive" or "resistant" with regards to effect of antimicrobial procedures.

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Consider a metabolic pathway under allosteric regulation. Label the pathway components and the diagram showing a "before and after" of an enzyme under allosteric regulation.

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Drag the statement to the correct column based on whether it describes transcription/translation in prokaryotes versus eukaryotes. Two labels are not used.

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Identify the final electron acceptor at the end of the tandem photosystems of cyanobacteria when non-cyclic photophosphorylation is used.

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Identify the parts of a double-stranded section of DNA.

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Identify the steps in transcription. Not all labels are used.

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Label the components involved in the chemical reaction.

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Label the diagram of a single nucleotide. Only three labels will be used.

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Label the diagram of tRNA. Not all labels are used

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Label the diagram that shows the impact of enzymes on the energy level of chemical reactions

*picture

Label the diagram that shows the impact of enzymes on the energy level of chemical reactions.

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Which method(s) did the Idaho Bureau of Laboratories use to definitively identify the organism?

-16S rRNA gene sequencing -Sequencing of part of an RNA polymerase gene

Which of the following statements regarding bacterial genetics is/are TRUE?

-A change in genotype can change the phenotype. -An auxotroph has a different genotype than a prototroph. -An auxotroph has a different phenotype than a prototroph.

Please match each type of mutation with its appropriate description: -nonsense mutation -missense mutation -silent mutation -frameshift mutation

-A mutation that changes a codon that specifies an amino acid to a stop codon, resulting in premature termination of polypeptide synthesis -A mutation that results in changing a codon such that a different amino acid is specified -A mutation that changes a codon into a different codon, but both codons specify the same amino acid; this causes no change in the resulting polypeptide -A mutation resulting from an insertion or deletion of bases that causes a change in the reading frame of the mRNA

The three central metabolic pathways—glycolysis, the pentose phosphate pathway, and the tricarboxylic acid cycle (TCA cycle)—modify organic molecules to generate what three useful components for the cell?

-ATP -Reducing power -Precursor metabolites

Match each of the following methods for preservation of perishable products with its description: -Reducing the available water -Chemical preservatives -Low-temperature storage

-Additions of sugar or salt, or subjecting the food to a high vacuum environment. -Must be non-toxic. Weak organic acids such as benzoic or sorbic acids often used. Nitrate and nitrite can also be used to inhibit germination of endospores of C. botulinum. -Slows or stops critical enzyme reactions in some (but not all) microorganisms.

1. ______ refers to energy-requiring metabolic processes that result in the biosynthesis of macromolecules and cellular structures. 2. Which of the following is not a catabolic process? 3. The Tricarboxylic Acid Cycle (TCA cycle) occurs after ______.

-Anabolism -Protein synthesis -glycolysis

Select the correct statements about autoclaving

-Autoclaving involves the use of both temperature and pressure -adding pressure to the autoclave increases the temperature of the steam in it -autoclaving is consistently effective in sterilizing most objects -biological indicators such as heat resistant endospores are used to ensure that an autoclave is working properly

Which of the following is/are true about CRISPR?

-CRISPR loci can reveal a historical record of phage infections of a bacterial cell. -CRISPR systems act as a barrier to horizontal gene transfer

Please select all of the differences between DNA and RNA to test your understanding of these nucleic acids.

-DNA is double-stranded, RNA is single-stranded. -DNA nucleotides contain deoxyribose whereas RNA nucleotides contain ribose. -There are multiple types of RNA with different functions whereas there is only one type of DNA

Match each of the following items that may influence the selection of an antimicrobial procedure with its correct description/rationale: -Composition of the item -Type of microbe -Risk for infection -Environmental conditions -Number of microorganisms

-Different materials respond differently to control measures. Some may even be destroyed by certain methods, preventing their use. -Certain microbes are highly resistant to killing methods (e.g. endospores). -Items that may come into direct contact with body tissues are more likely to cause serious infections if contaminated. -Dirt, grease, and bodily fluids in/on an area can interfere with control methods, as can temperature, pH, and even humidity levels. -It takes longer to kill a large number of microbes than a small number.

Which of the following chemicals is/are suspected carcinogens?

-Formaldehyde -Ethylene oxide

Which of the following compounds can be generated from precursor metabolites produced during glycolysis?

-Glycerol, a component of lipids -Some small amino acids like alanine, leucine, and valine. -Peptidoglycan, a component of bacterial cell walls.

The breakdown products of proteins can enter which of the following metabolic pathways?

-Glycolysis -TCA cycle -Pentose phosphate pathway

Select which of the following were used by laboratory personnel to initially identify the bacteria in the knee fluid as F. tularensis.

-Gram-staining -Metabolic capabilities

Please select the statements that are true of inducible operons to test your understanding of the differences betweeninducible and repressible operons.

-Inducible operons often contain genes for enzymes that function in catabolic processes. -Inducible operons will be "turned on" in the presence of the substrate and "turned off" in its absence -The lac operon is an example of an inducible operon.

Match each mechanism of resisting phage infection with its description: CRISPR system Restriction-modification systems. Preventing phage attachment.

-Insertion of small fragments of phage genome into host chromosome, giving the cell a "memory" of previous attempted infection and a way to recognize and destroy that foreign DNA in the future. -Modifying self-DNA shortly after it's produced, followed by using restriction endonucleases to digest DNA that lacks modification. -Changing or covering up the molecules on the surface of the bacterium to which the phage particle binds.

Why isn't colistin used very often to treat infections?

-It can cause serious kidney damage -It can cause nervous system problems.

What do we learn about E. coli from this report?

-It is Gram-negative -It can cause urinary tract infections

Select which of the following might impact the results of this experiment.

-Length of time washing hands -Type of soap -Section of lab floor sampled by each volunteer.

Which of the following is NOT a method of genotypic typing?

-MALDI-TOF

1. Hydrogen is transported from other reactions to the electron transport chain by ______. 2. Hydrogen consists of 3. During the electron transport chain, ATP will be made from 4. Which of the following contain a metal ion that can accept and donate electrons?

-NADH and FADH2 -one proton and one electron. -ADP + Pi -Cytochromes

Which of the following would be an example of occupational exposure for a healthcare worker?

-Needle stick -Cut with sharp object such as scalpel. -Contact of mucous membranes with blood

Match each of the following types of enzymes with its description. Inducible Constitutive Repressible

-Not routinely produced at significant levels, but their synthesis can be turned on when needed. These are often used in the transport and breakdown of specific energy sources. -Synthesized constantly, these enzymes usually play a critical and indispensable role in central metabolic pathways. -These are produced routinely, but their synthesis can be turned off when they are no longer required. These are generally used in anabolic (biosynthetic) pathways.

Which of the following statements about the figure below are TRUE?

-The green pigment produced by this organism may aid in identification of the organism. -The organism shown on the agar plate is likely a Pseudomonas species.

Match each type of radiation with its description: -Ultraviolet radiation -Ionizing radiation -Microwaves

-Not very penetrating radiation. Easily stopped by interfering materials. Works by producing thymine dimers in DNA strands. Most effective at close range and with long duration of exposure. -High energy radiation that directly destroys DNA and damages cytoplasmic membranes. It can also cause indirect damage by producing reactive oxygen species (ROS). -Doesn't affect microorganisms directly, but can generate heat in fluids which can indirectly kill microbes.

Why did Hershey and Chase use 32P and 35S in their experiments instead of the radioactive isotopes 14C or 13N?

-Nucleic acids have P in them while proteins do not. -Proteins have S in them while nucleic acids do not. -Amino acids and nucleotides both contain C and N.

Which of the statements about DNA and RNA are FALSE?

-RNA polmerase requires a primer -Eukaryotic RNA is typically polycistronic

Please place the following events in transcription in the correct order.

-RNA polymerase binds to the promoter region just upstream of the gene. -RNA polymerase unwinds the DNA at the promoter site and begins to transcribe the template strand of DNA. -RNA polymerase moves along the template strand of DNA adding complementary RNA nucleotides, extending the mRNA -Transcription continues until a terminator site in the DNA is reached. -The mRNA transcript is released.

Which of the following statements about polymerases are INCORRECT?

-RNA polymerase can only add nucleotides to an existing nucleotide sequence -RNA polymerase synthesizes a new strand of RNA from an amino acid template

Match the enzymes involved in DNA replication with their functions. -Primase -DNA gyrase -DNA polymerase -DNA ligase -Helicase

-RNA primer synthesis -Temporary breaking of DNA strands -DNA synthesis -Joining fragments of DNA -Unwinding the DNA helix

Match the term to its description to test your understanding of the use of moist heat to control microbial growth: -steam under pressure -pasteurization -commercial canning

-Requires use of an autoclave. To sterilize, temperature must reach 121°C for a minimum of 15 minutes. -Heat applied to beverages to prevent spoilage and kill pathogens. High-temperature-short-time protocols include holding liquids at 72°C for 15 sec. Does not sterilize. -Uses an autoclave called a retort to destroy the endospores of Clostridium botulinum. It will not destroy the endospores of some thermophiles

Identify what investigations would need to be done to eliminate the possibility that patient A contracted hepatitis C by occupational exposure at the facility where she worked.

-Reviewing records for all patients at the facility. -Onsite inspection of the facility for evidence of HCV -Observation of the safety practices used by staff at the facility

1. What methods are used by scientists to determine the genetic relatedness of the resistance genes in the microorganisms mentioned in this case? 2. Discuss what is meant by a BLAST search and how it could be used in the above process. 3. Discuss other methods besides antibiotic therapy that are necessary in controlling nosocomial infections caused by A. baumannii. Are these similar to those used in the control of nosocomial infections caused by other microorganisms? 4. Related to this case, how is antibiotic susceptibility testing conducted? 5. Describe the concept of selective toxicity and discuss the selective toxicity of colistin, one of the few antibiotics available to treat A. baumannii. 6. Conduct additional research and discuss examples of genetic recombination among microorganisms occurring in nonmilitary hospitals, leading to drug resistant nosocomial infections.

-Scientists used laboratory characterization in this article and other methods such as BLAST or microscopic investigation can also be used -BLAST stands for Basic Local Alignment Search Tool. This tool compares the composition or protein sequence of biological sequences to help find similarities and identify gene families. This article discussed bacteria strands being transferred to A. baumannii. Being able to locate the source of the bacteria and identify it is helpful for determining how to treat it -Colistin can be used to treat this but is often avoided due to its high toxicity. The article discussed the difficulty in treating nosocomial infections but that the implementation of infection-control measures is the best way to control these infections caused by A. baumannii. Sanitation procedures are helpful in preventing all kinds of bacteria. However, most bacteria are not as antidrug resistant as A. baumannii -The article says that antibiotic susceptibility testing is conducted through microdilution -Selective toxicity is when a drug targets specific sites on a microorganism to avoid infection. Colostin is affective against Gram negative bacteria and can be combined with other agents to treat A baumannii. -Research shows that nosocomial infections are common due to the constant exposure of different patients with different infections who are contaminating the hospital environment which can lead to horizontal gene transfer. This random combination could lead to drug resistant nosocomial infections

Please match the term with its description to test your understanding of microbial control terminology: Preservation Decontamination Sterilization Disinfection

-Slows microbial growth but does not reduce the number of existing microbes. -Mechanical removal of most microbes from living or inanimate surfaces -Destruction of all microbial life -Reduction of most microbial life on inanimate surfaces

Which of the following compounds can be generated from precursor metabolites in the TCA cycle?

-Some amino acids like aspartate, glutamate, and proline. -Certain protein components.

Match the important points regarding selection of an appropriate germicide with the description/rationale that fits it best: -Compatibility with the material being treated -Activity in the presence of organic matter -Storage and stability -Cost and availability -Toxicity

-Some substances are negatively affected by treatment with some germicides (i.e. corrosives damaging metals/rubber). -Some germicides may become less efficient when used in/on areas with organic matter. -Some germicides may lose efficiency over time, or may be required in very large amounts that would make them impractical for frequent applications. -Some germicides are highly effective, but are rare and/or expensive. -All germicides are somewhat harmful to humans and the environment. This parameter identifies HOW harmful the chemical is.

The researcher inoculates the test population of bacteria onto glucose salts agar containing penicillin and also on nutrient agar containing penicillin. She counts 25 colonies on the glucose salts plate lacking histidine and 32 colonies on the nutrient agar. Which of the following statements is TRUE?

-The colonies on both plates contain penicillin-resistant mutants. -The glucose salts plate contains some mutants.

1. What is oxidation? 2. Early in glycolysis, two phosphates are added to the glucose molecule. These phosphates come from 3. During glycolysis, a single 6-carbon molecule of glucose is converted to two 3-carbon pyruvate molecules. During the later steps in this process, how many molecules of ATP are generated? 4. The two 3-carbon molecules glucose is split into are converted through a series of steps into pyruvate. During these steps 5. After glycolysis, pyruvate can be converted into ______ under anaerobic conditions.

-The loss of electrons from a molecule. -breaking down ATP -4 -NAD+ is converted to NADH. -lactic acid

Consider the figure and check the CORRECT statements.

-The nucleobase shown in yellow should be a C -The CH3 groups alert the mismatch repair system to which DNA strand is the template strand. -Without the CH3 groups, it is possible that the mismatch repair system would replace the G nucleobase (purple arrow) with an A.

Which of the following might have alerted the laboratory personnel to the fact that the organism isolated from the patient's knee had been misidentified?

-The organism grew much better under anaerobic conditions than under aerobic conditions. -The patient had not been exposed to any possible sources of Francisella tularemia -The patient did not have fever, which is typical of tularemia.

Why would an organism use fermentation to generate ATP?

-The organism lacks an electron transport chain. -A suitable inorganic terminal electron acceptor is not available.

Distinguish between genotype and phenotype: phenotype genotype

-The organism's observable characteristics. For example, presence of a flagellum -The genetic makeup of the organism—in other words, the DNA sequence.

Match the taxonomic principles with their definitions: Nomenclature Identification Phylogeny Classification

-The system of assigning names to organisms. -The process of characterizing an isolate to determine the group to which it belongs. -Evolutionary relatedness of organisms -The process of characterizing an isolate to determine the group to which it belongs

Consider the image you labeled showing a metabolic pathway under allosteric regulation. Imagine if the final enzyme in the pathway was under allosteric regulation instead of the first. What impacts would this have?

-There would be a buildup of intermediate b. -The reaction would be less efficient.

Which of the following facilitated the persistence of M. abscessus in the water lines at Practice A?

-These bacteria are not destroyed by commonly used disinfectants. -The water lines at the practice were not flushed with bleach regularly. -M. abscessus can form biofilms that are difficult to remove.

Which of the following statements accurately describe biochemical pathways? Choose all that apply.

-They convert an initial substrate through a series of steps into an end product -They are well-organized and structured -They can be linear, branched, or cyclical. -They are carefully regulated

Match five methods used to characterize different strains of prokaryotes with their descriptions: -Biochemical typing -Serological typing -Molecular typing -Phage typing -Antibiograms

-This type of testing relies on unique metabolic activities of the microbe. -This type of testing relies on the use of specific antibodies to detect unique antigens on the microbe. -This type of testing relies on detecting specific differences in the microbe's DNA or DNA patterns. -This type of testing relies on the use of specific bacteriophages to detect a particular microbe strain. -This type of testing relies on antibiotic susceptibility patterns generated by specific microbes.

1. What does the word "transcribe" mean? 2. Transcription begins when RNA polymerase binds to the 3. What role does the sigma factor of RNA polymerase have in transcription? 4. If one strand of DNA contains the bases ACAGT, what would be the complementary bases on the mRNA strand? 5. Synthesis of mRNA is 6. What happens when a hairpin loop forms in mRNA?

-To make a copy -promoter on DNA -It recognizes and binds to the promoter region of the template DNA -UGUCA -in the 5' to 3' direction with new nucleotides being added to the 3' end of the mRNA molecule. -The RNA polymerase and the mRNA dissociate from the DNA.

Match the types of RNA with their function tRNA mRNA rRNA

-Type of RNA molecule that carries amino acids to the growing peptide chain during translation. -Type of RNA molecule that contains the genetic information decoded during translation. -Type of RNA molecule present in ribosomes.

Match the chemical mutagens with their descriptions: Base analogs Intercalating agents Alkylating agents Transposons

-Used in place of normal nucleobases -Insert between base pairs -Add CH3 and others to nucelobases -Randomly insert into DNA

Match the germicide with its use.: High-level disinfectant Intermediate-level disinfectants Low-level disinfectant Sterilant

-Used to treat semi-critical instruments such as gastrointestinal endoscopes. -Used to treat non-critical instruments such as stethoscopes. -Used to treat floors, furniture, walls and so on. -Used to treat heat-sensitive critical instruments such as scalpels.

Select all the TRUE statements from this article.

-Veillonella parvula is a Gram-negative, anaerobic coccus -The laboratory personnel who made the initial identification were given prophylactic antibiotics.The laboratory personnel who made the initial identification were given prophylactic antibiotics. -16S rRNA gene sequencing identified the organism in the knee fluid as Veillonella species.

1. What was the most likely mode of transmission of Cryptosporidium at the Seneca Lake State Park Sprayground? 2. True of false: Cryptosporidium was not susceptible to disinfection through filtration and chlorination of the spray park's water supply. 3. What type of radiation in sunlight causes damage to DNA? 4. UV irradiation inactivates Cryptosporidium because it 5. UV water treatment systems are effective in treating

-Water-borne -true -UV radiation -blocks the action of DNA polymerase -bacteria, viruses and protozoans

1. The F plasmid encodes for 2. The first step in conjugation is 3. After the transfer of the F plasmid is complete

-the F pilus -contact between the donor and recipient -the F- cell becomes F+

Which of the following statements about translation are CORRECT?

-a codon can code for "punctuation"--for example, where translation should start or stop -two different codons can code for the same amino acid -a codon is found on mRNA while an anticodon is found in the tRNA

1. Plasmids are 2. A recombinant organism is 3. If you find that a particular plasmid has an R factor, the bacteria that has it will be 4. The main advantage for bacteria that have the ability to carry out conjugation and other forms of genetic exchange is that

-able to replicate independently of the chromosome -one that that contains genes from another organism -resistant to certain antibiotics -they become genetically diverse

When you add hydrogen peroxide to an isolated bacterial colony, bubbles form. Identify two conclusions you can make about the bacterial cells:

-are catalase positive -break down hydrogen peroxide

1. A virus that infects bacterial cells is called a ______ 2. After entry of the bacteriophage into the host cell, a phage enzyme 3. During maturation or formation of phage particles, 4. In transduction, bacterial DNA is transferred to a new cell when 5. When the bacteriophage transfers bacterial DNA into a recipient bacterial cell, that DNA

-bacteriophage -breaks the host DNA into fragments -a few phage heads may surround fragments of host bacterial DNA -it is injected by the virus carrying bacterial DNA -can integrate into the chromosome

1. The coenzyme NADH is generated by 2. The electron carrier proteins in the electron transport chain shuttle electrons to 3. During the electron transport chain in bacteria, protons are 4. In anaerobic respiration, the terminal electron acceptor would also be oxygen. 5. The enzyme ATP synthase uses energy from ______ to make ATP.

-by oxidation reactions in glycolysis and the Krebs cycle -a terminal electron acceptor. -shuttled to the outside of the cell membrane. -false -protons re-entering the cell.

1. DNA polymerase 2. On one of the strands of bacterial DNA, the new complementary strand is synthesized discontinuously in small pieces of DNA called 3. One bacterial chromosome replicates to become two chromosomes with

-can only add nucleotides in a certain direction -Okazaki fragments -each made of one strand of DNA from the original chromosome and one newly synthesized strand.

A suffix used to describe a killing action would be

-cidal

1. UV light causes ______ bonds to form between adjacent thymines on the same strand of DNA. 2. True or false: Cells can replicate and transcribe DNA that contains thymine dimers. 3. Photolyase is an enzyme that cells use to repair thymine dimers in a ______-dependent manner. 4. Excision repair, which is also used to correct thymine dimers, requires 5. What enzyme(s) is/ are involved in replacing the removed nucleotides following excision repair?

-covalent -false -light -none of these -DNA polymerase, followed by DNA ligase

Match the listed objects and compounds with the appropriate method used to destroy microbes and viruses on/in them: Moist heat Dry heat Radiation

-culture media and milk -medical waste, inoculating loop, medical carcasses -meat products and heat sensitive medications

1. Glycolysis takes place in the ______. 2. The TCA (Krebs) cycle takes place in the mitochondria of eukaryote cells. Where does it take place in prokaryote cells? 3. What happens to carbon dioxide after it is released during reactions of the TCA cycle? 4. How many molecules of NADH are generated for each turn of the TCA cycle? 5. How many ATP molecules are produced in the TCA cycle for each glucose molecule that enters glycolysis? 6. For each glucose molecule that enters glycolysis, how many times does the TCA cycle "turn"?

-cytoplasm -The cytoplasm -It diffuses out of the cell. -3 -2 -2

1. In the beginning of transformation, ______ binds to the target cell. 2. During the entry of the donor DNA into the recipient cell, 3. The donor DNA 4. Mismatch repair is activated by 5. As a result of mismatch repair during transformation:

-double-stranded DNA -one strand is broken down by nucleases -pairs with a homologous region of the recipient DNA -any difference between the nucleotide sequence in the donor and recipient DNAs -cells may have either original DNA or donor DNA in them

1. Glycolysis makes products that feed into 2. The two 3-carbon molecules that glucose is split into during glycolysis are converted through a series of steps ending in what 3-carbon molecule? 3. For each glucose molecule broken down by glycolysis, how many net ATP molecules are produced?

-electron transport chain, TCA cycle AND fermentation -Pyruvate -2

If the gene for the lac operon repressor is non-functional, what would happen if the cell were grown in medium with an unlimited supply of both lactose and glucose?

-the cells would degrade glucose, but not lactose -enzymes for degrading glucose would be made but not those for degrading lactose

1. One advantage of having genetic control mechanisms is 2. Coordinated sets of genes that are regulated as a single unit are referred to as ______. 3. A mechanism that blocks transcription

-enzymes are only produced when they are needed. -operons -will block the production of mRNA

1. A. baumannii is easily removed from hospital surfaces by disinfectants. 2. Because all of the genes coding for antibiotic resistance have been found to come from other organisms, A. baumannii most likely acquired them through 3. Nosocomial infections caused by A. baumannii in civilian hospitals are not a major concern. 4. Based upon information in Chapter 8 and the case study, it appears that multidrug resistant strains of bacteria such as A. baumannii:

-false -conjugation or a similar process of genetic exchange -false -acquired their resistance genes from other bacteria in healthcare facilities

1. A segment of DNA encoding a protein or an RNA molecule is a ______. 2. A ______ is the physical expression of the genes present and can change depending upon what genes are turned "on". 3. Why is translation needed?

-gene -phenotype -The subunits of nucleic acids are nucleotides, while those of proteins are amino acids.

Please select the statements that describe features of transcription and translation found in eukaryotes but not in prokaryotes.

-genes are interrupted by intervening sequences -a tail of multiple adenine ribonucleotides is added to the mRNA transcript -the mRNA transcript must pass through pores to get out of the nucleus -the RNA transcript is processed to remove introns and splice together exons

1. The classic transformation experiment done by Griffith used 2. Transformation is a form of horizontal gene transfer that involves homologous recombination. Homologous recombination is 3. In addition to transformation, the other two forms of horizontal gene transfer are

-harmless and virulent strains of Streptococcus pneumoniae -genetic recombination between similar or identical nucleotide sequences -conjugation and transduction

1. F+ cells 2. The F pilus is 3. The F pilus binds to 4. The plasmid is mobilized for transfer when 5. Plasmid DNA is transferred

-have a plasmid and are donors in conjugation -a protein appendage that attaches the two cells together -specific receptors on the cell wall of the recipient -an endonuclease cleaves it at the origin of transfer -in single-stranded form

Which of the following kills food microbes, rather than just reducing their growth?

-irradiation

1. When a repressor binds to the operator site on DNA, 2. Repressible operons (such as the arg operon) 3. In some degradative pathways, in the absence of an inducer (such as arabinose),

-it blocks RNA polymerase binding and mRNA synthesis -are usually in the "on" mode -the activator protein can't bind to DNA, and RNA polymerase can't bind to the promoter site

Select the statements about ionizing radiation that are true.

-it can be used to sterilize medications -it can be used to sterilize medical equipment -it can be used to reduce spoilage organisms on food

1. When a bacterium is grown on glucose only, 2. When an amino acid such as arginine binds to a repressor, 3. In the absence of lactose, 4. In an inducible operon, when a substrate or inducer is present, 5. Binding of an activator to an activator binding site on DNA

-it must synthesize all the amino acids it needs -the repressor binds to the operator site -a repressor protein binds to the operator -it reacts with the repressor and inactivates it -enhances the ability of RNA polymerase to bind to the promoter site

1. During the process of transformation in the lab setting, cells are plated on selective media to 2. Cells that are capable of bringing DNA from their environment into the cell through their cell wall are ______. 3. Transformation is facilitated by 4. If a Gram-positive competent cell takes up DNA containing a penicillin resistance gene, what would be added to a selective medium to isolate the transformants?

-make sure that only transformants grow -competent -proteins on the cell wall that bind DNA -Penicillin

Categorize the given chemicals according to their uses. Wounds Medical instruments Soaps

-metals, halogens -aldehydes, ethylene oxide, peroxygens -biguanides, phenolics

Germicides known as ____________ can destroy all microbes including both bacterial endospores and all types of viruses. ____________ disinfectants destroy all viruses and vegetative cells but will not kill endospores. ____________ disinfectants destroy vegetative cells and some, but not all, viruses. They are unable to kill endospores even when used for a prolonged period of time. Germicides known as ____________ disinfectants kill vegetative cells except for mycobacteria and are unable to destroy nonenveloped viruses and endospores.

-sterilants -high level -intermediate level -low level

1. RNA is a chain of ______. 2. What three components make up RNA subunits? 3. What component of RNA is different from one person (or one bacterium) to the next? 4. The purpose of RNA synthesis is to provide a new copy of DNA as the original strand deteriorates over time. 5. Which nucleotide is not found in RNA?

-nucleotides -Phosphate, nitrogenous base, ribose sugar -The order of nitrogenous bases -false -Thymine

1. Bacteriophages adsorb or attach 2. The basic parts of a bacteriophage are 3. A difference between transferring plasmids and DNA fragments between bacterial cells is 4. Examples of advantageous genes that can be transferred by transduction are genes for

-only to members of the same bacterial species -an icosohedral head, tail, tail pins, and fibers -plasmids can replicate independently -All of these

1. The specific point on the DNA molecule where replication begins is the 2. Early in the process of DNA replication, the enzyme ______ separates the two strands. 3. DNA polymerase 4. If an organism lost the ability to make primase, what would it be unable to do? 5. Two different mechanisms for copying the DNA strands are used because

-origin of replication -helicase -requires a template for the synthesis of DNA. -Add a short sequence of complementary RNA to the existing DNA strand -the strands are oriented in opposite directions

1. The terminal electron acceptor in aerobic respiration is ______. 2. Glycolysis is the central metabolic pathway that involves the breakdown of ______. 3. The energy released during the reactions of glycolysis is used to form ______. 4. Cells prefer to use carbohydrates as energy sources because

-oxygen -glucose -adenosine triphosphate -they are such good donors of hydrogen and electrons

1. The bond connecting amino acids is a ______ bond. 2. If you know the sequence of nucleotides in mRNA, you can deduce the DNA sequence it was transcribed from. 3. Which of the following shows the direction genetic information flows? 4. Protein synthesis occurs on the ______. 5. Replication, transcription and translation take place in the bacterial cytoplasm.

-peptide -true -DNA → RNA → protein -ribosomes -true

1. After host cell DNA is broken down by a viral enzyme, 2. Generalized transduction occurs when 3. Two bacterial genes are transduced simultaneously. What does this suggest about the location of the two genes relative to each other?

-phage DNA is replicated and phage coat proteins are produced -a bacteriophage packages a piece of bacterial DNA during replication -The two genes must be close together on the bacterial chromosome

1. The three basic parts of a DNA nucleotide are 2. Which of these is base-paired correctly? 3. The two strands of DNA are joined to each other or held together by 4. The two strands of the DNA molecule are ______.

-phosphate, deoxyribose sugar, nitrogenous base. -TA -hydrogen bonding -antiparallel

1. The main purpose of cellular respiration is to 2. Where do NADH and FADH2 go after being produced in the TCA cycle? 3. True or false: In prokaryotes and eukaryotes, the TCA cycle takes place in the mitochondria. 4. Where does the TCA cycle take place in bacteria?

-produce energy -Electron transport chain. -false -Cytoplasm

1. Translation of mRNA into protein begins before transcription is complete in ______. 2. In prokaryotes, the mRNA transcript encounters ribosomal subunits immediately as it leaves the DNA. 3. A(n) ______ is a cluster of genes that perform related functions, found in ______. 4. Eukaryotic mRNA contains non-coding regions called ______. 5. Introns are removed and exons are spliced together 6. Eukaryotic mRNA usually specifies multiple proteins.

-prokaryotes only -true -operon, prokaryotes -introns -before translation -false

Which of the following play a role in microbial sensing of the environment?

-quorum sensing -two component regulatory systems -antigenic variation -phase variation -sensor and response regulators

Categorize the given medical instruments: critical semi critical non critical

-scalpel, needles, venous catheter -gastrointestinal endoscope, endotracheal tube, thermometer -stethoscope, blood pressure cuff

1. Acinetobacter baumannii is a common resident of ______. 2. Infections caused by A. baumannii have most frequently been seen in 3. A "nosocomial" infection is an infection acquired through 4. Acinetobacter baumannii may have acquired resistance to multiple antibiotics through

-soil and water -soldiers at military hospitals -a hospital stay -all of these

1. In bacteria, the electron transport chain is located in 2. In aerobic respiration, the last carrier protein in the electron transport chain transfers 3. The electron transport chain is part of ______.

-the cytoplasmic membrane -two electrons to oxygen. -respiration

1. In the cases presented, what was the most probable route of transmission of the pathogen? 2. Although the epidemiological data collected from interviews implicated contaminated recreational water as the source of the outbreaks, negative results from the recreational water samples were obtained in most cases. Please explain this apparent contradiction. 3. Evaluate the effectiveness of the hyperchlorination of recreational waters at the facilities in these cases. 4. Discuss the role of public education in reducing the transmission of Cryptosporidium and other pathogenic microbes at recreational water venues. 5. Knowing that public water supplies to towns and cities are well purified by various means, do Cryptosporidium outbreaks still occur? Explain. 6. Conduct additional research and discuss other recreational water activities that pose a risk for microbial infection. What genera of organisms most commonly cause these types of infections?

-the pathogen remained in the water despite filtration and chlorine. So this recycled water included the protozoan and was exposed to all visitors who came in contact with the water -I assume that since the pathogen is so small and that since the park is 11,000-square-foot that the protozoan was so distributed that it was not enough to represent a positive result -Hyperchlorination will be ineffective for removing Cryptosporidium specifically because Cryptosporidium is resistant to Chlorine -Proper purification is obviously important to reduce the amount of pathogens in recycled water. However pathogens come in many different forms and are resistant to different things methods of purification. This is why it is important to consider and perform many different methods to remove these different types of pathogens -It is still possible for Cryptosporidium to occur if one were to come in contact with contaminated water that was not purified. Examples include drinking river water while camping or being exposed at a public pool because people are constantly entering and contaminating the water -Certain water sports can also be increase a risk for microbial infections. In addition, children are also more likely at risk considering they are more likely to both contaminate water by producing feces into the water and are more likely to accidently swallow more water. Bacteria, viruses, and protozoans can all contribute to water borne microbial infections but I think bacteria is most common.

1. Translation is needed because 2. The initial transfer RNA occupies the _____ site on the ribosome. 3. _____ are groups of three bases in mRNA that specify one amino acid in the amino acid chain. 4. If the codon GGU is positioned in the A site of the ribosome, which of the following will occur? 5. What usually terminates the process of translation?

-the subunits of DNA and RNA are nucleotides while those of protein are amino acids -P site -Codons -A tRNA with the anticodon CCA will deliver its amino acid to the site. -Presence of a stop codon on mRNA.

1. The process of transcription is similar to 2. After mRNA is made, what generally occurs? 3. Unlike DNA, RNA is usually single-stranded.

-the synthesis of the leading strand during DNA replication -It is translated to protein -true

Today, microorganisms are consistently classified based on

-their ribosomal RNA sequences. -the similarity of their nucleotide sequences to other organisms. -nucleic acid amplification tests.

Select the reasons sugar or salt can be used for food preservation. Check all that apply.

-they may cause plasmolysis -they dehydrate the bacterial cells -they create a hypertonic environment, unfavorable for growth

1. Prokaryotes lack membrane-enclosed organelles. 2. Which of the following occur(s) in both prokaryotes as well as eukaryotes? 3. The sequence of DNA bases ultimately determines the sequence of amino acids in a polypeptide.

-true -All of these -true

1. Only eukaryotic mRNA is processed before translation. 2. Translation of eukaryotic mRNA can occur in the nucleus after exons are spliced together. 3. Translation occurs on ribosomes only in prokaryotes. 4. The processes of transcription and translation differ between prokaryotes and eukaryotes in the following way:

-true -false -false -Prokaryotes transcribe and translate simultaneously

RNA polymerases

-uses DNA as a template to synthesize RNA -synthesizes molecules shorter than the chromosome -synthesize chains of ribonucleotides

Review the chart showing hypothetical data for a similar case. The purple line represents VRSA. The orange line shows VSSA (vancomycin-sensitive S. aureus). At what dose of vancomycin is the VSSA population reduced by approximately two thirds?

0.002mg/mL

Repair mechanisms that occur during DNA synthesis are 1. mismatch repair 2. proofreading by DNA polymerase 3. light repair 4. excision repair 5. SOS repair

1 and 2

Place the following events that occur in DNA replication in the correct order.

1-specific proteins bind the origin of replication and separate the two strands of DNA, forming two replication forks 2-primase synthesizes RNA primers 3-DNA polymerases build DNA by adding nucleotides onto the primers, extending them 4-the leading strand is synthesized continuously while the lagging strand is synthesized in Okazaki fragments 5-a different DNA polymerase removes the RNA primers and replaces them with DNA 6-DNA ligase joins the Okazaki fragments

Explain the difference between a biotype and a serotype

A biotype is the biochemical profile of a particular microorganism, while the serotype is the difference in its surface structures/antigens that will lead to separate immune responses from an organism (characterized by presence of different antibodies in the individual's serum).

Chlorine is safely used to disinfect waste liquids, some medical instruments, and various surfaces. It is readily available in liquid household bleach but bleach must be diluted because high concentrations are toxic and corrosive. To obtain an effective concentration of chlorine when using household bleach, a 1:100 dilution is made. This means that ______ mL of bleach is added to ______ mL of water

1.0; 99

In a one D process, how many D values would it take to reduce a population of 1010 cells to one survivor?

10

Typical conditions used for sterilization are

121°C at 15 psi for 15 minutes

Your brother goes on to explain the concept of decimal reduction (D-value) time to you. To illustrate his point, he tells you that if the D-value for Giardia was 3 minutes and the starting number of cells was 104, the time it would take to eliminate all of the Giardia cells would be

15 minutes

Which of the rRNA molecules has proven the most useful in taxonomy/identification?

16S

Which of the rRNA molecules is most useful for bacterial identification?

16S

Which type of ribosomal RNA is most often used in taxonomy?

16S

Which method did the researchers use to compare the gut bacteria of the Inuit people with those of people form Montreal?

16S rRNA sequencing

To study the phylogeny of eukaryotes,

18S rRNA is used.

Arrange the following proteins in the correct order in which they participate in DNA replication.1 = Primase2 = Helicase3 = DNA ligase4 = DNA polymerase

2, 1, 4, 3

How many nucleotides are in a codon?

3

DNA polymerases use their ______ activity to remove a mismatched base pair

3' -> 5' exonuclease

Without changing the sequence or the orientation of the sequence(s), which is/are complementary to the sequence 5' AGGCUAAC 3'?

3' TCCGATTG 5'

Consider the figure. If methylguanine replaces guanine in a DNA strand with the sequence 5'CGA3', the resulting change in the complementary strand after DNA replication would be

3'GTT5'

Arrange the following in the proper sequence in which they occur during a single PCR cycle. 1. Addition of DNA nucleotides by Taq polymerase 2. Complementary base pairing between primers and target DNA 3. Heat separation of strands of target DNA

3, 2, 1

You are studying a cell with 20% of its DNA composed of T nucleotides. What percentage of the nucleotides are C?

30%

Look at the figure below, which shows fragments of DNA, cut by restriction endonucleases and separated by size on a gel. Which DNA samples are likely to be from the same bacterial strain?

4 and 5

The decimal reduction time is the time it takes to kill 90% of a given bacterial population under certain conditions. If 90% of a population of 100,000 bacteria is killed in 10 minutes, how long would it take to reduce the population to 10 cells?

40 min

If a 75 base-pair fragment of DNA has 25 cytosines in it, how many adenines would you expect it to have?

50

How many bacteria were scanned in an effort to find those with the mcr-1 gene?

55 x 10^3

If a process kills 90% of the organisms per minute, how many minutes would it take to kill all organisms when starting with 100,000 organisms?

6 minutes

There are ______ codons to code for the 20 possible amino acids.

61

How many agar plates do you have to analyze at the end of your experiment?

90

You tell Jasmine that it is important that she use a sterile instrument to pierce Paul's boil. Jasmine does not know what "sterile" means or why she needs to use something sterile for her "boil surgery", so you explain. Select the best answer.

A sterile instrument is free of all microbes, endospores, and viruses. Jasmine needs to use a sterile blade because it will come into contact with Paul's tissues, and is thus a critical instrument.

Which regions of the gene (or segment of DNA) shown here encodes the amino acid sequence of a protein?

A, C, E

Which is TRUE about a crown gall tumor?

It results from the incorporation of bacterial plasmid DNA into the plant chromosome.

A graduate student is trying to isolate bacterial mRNA for an enzyme that will degrade trinitrotoluene (TNT). She's frustrated to find that the enzyme isn't produced when the bacterium in question is grown on nutrient agar. What might she do to solve the problem and obtain the mRNA?

Add TNT to the agar—this will drive synthesis of the enzyme to degrade it, leading to production of the mRNA the student is looking for.

Which change in a gene's DNA sequence would have the least effect on the eventual amino acid sequence produced from it?

Addition or deletion of three consecutive nucleotides

How could this type of scenario be avoided in the future?

All equipment/ supply carts in healthcare facilities should be disinfected between procedures

Chemical germicides

All of the answer choices are true. -may react irreversibly with proteins/enzymes. -may react with cytoplasmic membranes or viral envelopes. -may be disinfecting or even sterilizing. -are sensitive to dilution factor, time of contact, and temperature of use.

Which technique(s) is/are used to help identify and classify bacteria?

All of the choices are correct

Which is true about DNA replication?

All of the choices are correct.

The scientists responsible for the idea that RNA can act as a catalyst were

Altman and Cech

A quick microbiological test for potential carcinogens was developed by

Ames

Review the chart*. How many total bacteria are on the hands of the people who wash their hands with water only, assuming that each colony arises from a single cell?

Approximately 450

The three domain classification scheme uses

Archaea, Bacteria, Eukarya

Where is rRNA found in a cell, and to what cellular process is it essential?

Ribosomes; protein synthesis

Which of the following genes are likely to be found on a plasmid rather than on the bacterial chromosome?

BT toxin gene Chloramphenicol-resistance gene Oil degradation enzyme genes

Why might it be easier to identify the bacterium that caused pneumonia than one that caused a wound infection?

Bacteria that cause pneumonia can be identified with few tests because the lungs have no normal microbiota. Many bacteria are normally found on the skin however; these may be in the wound, complicating identification.

Select the best definition for "Gram-variable" bacteria.

Bacteria that stain either pink or purple.

Which of the following statements would NOT be good information for your sister?

Bacterial ribosomes and eukaryote ribosomes are identical

The report that genes direct the synthesis of proteins was first made by

Beadle and Tatum

The reference for taxonomic descriptions of bacteria is

Bergey's Manual of Systematic Bacteriology

What is the most important point in the first paragraph?

Biologists thought that yeast cells multiplying in grape juice convert sugar into CO2 and alcohol.

Initially, the patient was infected with methicillin-resistant S. aureus. Which of the following was/ were found in her foot ulcer after she received vancomycin for this first infection?

Both VRE and VRSA

During PCR, which primer anneals to DNA with its 3' end toward the center of the sequence to be amplified?

Both the forward primer and the reverse primer

GCCCAAAG is a molecule of

Cannot tell as written

You are studying the metabolism of the phototrophic green sulfur bacterium Chlorobaculum tepidum and realize that it is running a reversed TCA cycle! How do you explain this observation?

C. tepidum is using the reversed TCA cycle to fix carbon dioxide.

Which word in the description tells us that Hershey and Chase used high speed spinning to separate two things?

Centrifugation

Consider the growth of Sulfurospirillum halorespirans using lactate as a source of carbon and electrons, and perchloroethylene (PCE) as an electron acceptor. How would scientists classify this species based on its metabolism?

Chemoorganoheterotroph

Scientists isolated a new species of bacteria growing in sediments collected from a 63 meter deep site at the bottom of Lake Washington in Seattle This species, named Labrys methylaminiphilus, is capable of obtaining its carbon and energy needs from methylamine (CH3NH2), a derivative of ammonia (NH3) in which one H atom is replaced by a methyl (CH3) group. L. methylaminiphilus grows at a temperature range of 10-35°C, with optimal growth at 28-30°C, and a pH range of 4.0-9.5, with optimal growth at 5.0-7.0. Because methylamine is a single carbon compound resulting from the breakdown of decaying organic matter, methylotrophic ("methyl-feeding") bacteria like L. methylaminiphilus play an important role in carbon cycling in lake sediments and other environments. Consider the growth of L. methylaminiphilus on methylamine. How would you classify this species based on its metabolism?

Chemoorganoheterotroph

The researchers were also able to grow Sulfurospirillum halorespirans using hydrogen gas as an electron donor and acetate as a source of carbon, using perchloroethylene (PCE) as an electron acceptor. When demonstrating growth in this manner, how would scientists classify this species?

Chemoorganoheterotroph

Some enzymes require a cofactor or a coeznyme in order to be active. What is the difference between cofactors and coenzymes?

Cofactors are non-protein components that assist enzymes and are typically trace elements; coenzymes are organic cofactors that loosely carry molecules or electrons.

In which of the following does the donor cell direct the process?

Conjugation

What is the likely way other bacteria might acquire the mcr-1 gene?

Conjugation

Which of the following concerns would lead a user to wash an item after it had been treated with a germicide?

Corrosive residue left after treatment.

Please select the INCORRECTLY matched pair

D-value - time to destroy 10% of microbes present (correct: Critical instrument - scalpels and needles. Bacterial endospores - highly resistant. Sterilants - destroy all microbes including endospores and viruses. Incineration - burns cells to ashes)

A population of bacteria is breaking down some lipids to support microbial growth. Where do the products of lipid breakdown enter the central metabolic pathway?

Glycolysis TCA cycle

Strong chemical mutagens may be used to treat cancer cells. Is this a good or bad idea?

Good and bad—they're very good at killing cancer cells, but they could also be dangerous to non-cancerous cells.

At the beginning of the Calvin cycle, carbon dioxide is attached to ______.

RuBP

Based on the phylogenetic tree shown here, which organisms are most closely related?

D. radiodurans and T. aquaticus

Which statement regarding the Gram stain is FALSE?

Gram staining can be used to differentiate intestinal normal microbiota from pathogens—for example differentiating E. coli from Salmonella enterica.

Which tasks must a bacterial cell accomplish in order to multiply?

DNA duplication, RNA synthesis, protein synthesis

PCR requires all of the following EXCEPT

DNA ligase

The single-stranded ends of DNA molecules can be joined together by

DNA ligase

In 1970 Stanier proposed that classification be based on

DNA sequence

What type of molecule(s) could the following be? Check all that apply. AGCGCCGCAACGC

DNA, RNA

DNA is characterized by which of the following feature(s)?

Deoxyribose AND thymine

DNA transfer by conjugation is more efficient in a liquid medium setting, subjected to very mild agitation (stirring), rather than on an agar plate format. Why?

Direct cell-to-cell contact is required for this process, and this is more likely to be achieved in the fluid liquid format than on an agar plate (especially for relatively non-motile types of bacteria).

Choose which of the following best describe the difference between a disinfectant and an antiseptic.

Disinfectants are antimicrobial chemicals used on inanimate surfaces or objects to remove most of the pathogenic microorganisms. Antiseptics are antimicrobial chemicals that can be used on skin or tissues to achieve the same result

Which are essentially equivalent treatments?

Dry 200°C heat for 1.5 hours; wet 121°C heat for 15 minutes

E. coli 0157:H7 produces clear colonies on MacConkey agar, while common strains of the organism produce pink colonies on this medium. The organism stains pink in the Gram stain. Select the TRUE statement, given this information.

E. coli 0157:H7 does not ferment sorbitol AND is Gram negative

Please use the dichotomous key below to identify a bacterium with the following characteristics: stains pink in the Gram stain, produces no color when exposed to oxidase substrate, and produces both acid and gas when inoculated in lactose broth.

E. coli or other coliform

Which of the following is an example of phase variation?

E. coli producing pili for attachment to epithelial cells.

Which of the following are resistant to destruction by typical disinfection methods?

Endospores of Bacillus and Clostridium

Consider the image you labeled showing a metabolic pathway under allosteric regulation. Which enzyme in this pathway is most likely under allosteric control?

Enzyme a

Which of the following statements regarding bacterial gene control is FALSE?

Genes for constitutive enzymes can be turned on and off as necessary.

F+ refers to a cell containing

F plasmid

T/F: Aldehydes can be used to disinfect superficial wounds

False

Which of the following are signs and symptoms of M. abscessus infections?

Fever and pain. Swelling of the face Bone infections Swollen lymph nodes.

What is an isotope?

Forms of the same element that contain equal numbers of protons but different numbers of neutrons

How did the patients in this case acquire M. abscessus?

From contaminated water used during the dental procedure.

How do chemolithotrophs acquire energy?

From inorganic compounds

Which of the following is unlikely to be the recognition site of a restriction endonculease?

GCTTGC CGAACG (same but backwards)

Which may be or is an RNA molecule?

GGGCCCA and GCCCUUA

Why is it a good idea for a bacterial cell to be able to use glucose FIRST as an energy source (until it is depleted), THEN switch to lactose?

Glucose is an easier compound to break down and obtain energy from than lactose AND for conservation of energy: why use the energy to make the enzymes for breaking down lactose when glucose doesn't need any extra enzymes for breakdown?

E. coli is a Gram-negative bacillus that is found as intestinal normal microbiota. Which of the following would not be useful for an initial step in identifying E. coli O157:H7 strains in a stool sample?

Gram staining, because E. coli strains will appear identical using this approach

A breath test assaying for radioactive carbon dioxide may be used to indicate the presence of

Helicobacter pylori

If you were the lab technician trying to identify the causative organism of this foodborne outbreak, would you inoculate several biochemical tests at the same time, or would you inoculate each test after getting the results from the previous test?

I would inoculate several tests simultaneously, because most biochemical tests require at least 18 hours of incubation, so inoculating several tests simultaneously saves time and also aids in conclusive identification.

Which of the following statements about spontaneous mutation is TRUE?

If the mutation rate to antibiotic A is 10-9 per cell division, and to antibiotic B is 10-6 per cell division, the probability of the cell being resistant to both medications is 10-15.

Which is not true of RNA?

It contains both uracil and thymine

Is it as effective to take two antibiotics sequentially for an infection as it is to take them simultaneously, as long as the total length of time of the treatment is the same?

It depends. Provided that the majority of the infectious agent is killed off by the first drug, the likelihood that the few that are left would not also be killed by the second drug is low. However, simultaneous treatment should be more effective at eliminating all the microbes in the shortest time possible, and with the least probability of selection for multiple drug resistance mutations.

To maximize the number of thymine dimer mutations following UV exposure, should you keep human cells in tissue culture in the dark, in the light, or does it matter at all?

It doesn't matter—human cells don't have the enzymes needed for photorepair of thymine dimers

Why is the position of the first AUG after the ribosome binding site critical?

It establishes the reading frame

Which of the following statements is FALSE regarding Giardia?

It has a peptidoglycan cell wall

S. enterica can switch to anaerobic respiration in tetrathionate broth. What does this tell us about the organism?

It is a facultative anaerobe.

On further reading, you learn that strains of H. influenzae vary genotypically. Many of them have silent mutations. Select the TRUE statement regarding this type of mutation.

It is a point mutation—a single base pair is altered, causing the change of one amino acid in the protein that does not affect the function of that protein

Which is FALSE about the RNA transcript?

It is made in short fragments that are then stitched together

Which is true of iodine?

It is usually found as tinctures or iodophors

Which of the following about heat treatment is FALSE?

It produces toxic byproducts (correct: fast, reliable, cheap, safe)

Which is not true about mismatch repair?

It removes both strands in the mismatch area

Two bacterial genes are transduced simultaneously. What does this suggest about their proximity to each other within the original host genome?

It's highly likely that the two genes are located next to each other in the host cell chromosome. Since transduction results from a packaging error or an excision error that occurs during the infection cycle of the bacteriophage, the genes must lie close to each other to be transduced into a new cell simultaneously

From most general to most specific, which is the correct order?

Kingdom, phylum, class, order, family, genus, species

DNA in cells can encode for thousands of different proteins. Why do cells require mechanisms to regulate expression of the genes that code for these proteins?

Not all proteins are needed at all times, or in equal amounts. Regulating their expression saves energy and time.

Which of the following statements about the Ames test is FALSE?

Liver extract is added to provide nutrients

Please select the FALSE statement regarding phenotypic approaches to identifying microorganisms.

MALDI-TOF MS separates and sorts an organism's carbohydrates by mass, generating a profile that provides a fast way to identify an organism grown in culture.

Which of the following is NOT a method used to differentiate E. coli O157:H7 from other strains based directly on genotype?

Matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS)

Identify the difference between the use of depth filters and membrane filters in sterilizing fluids.

Membrane filters have smaller pores than depth filters, but depth filters have complex passages that retain microbes while letting the fluid through. Both methods are efficient.

Which of the following methods is used to help identify prokaryotes by examining how bacteria respond to different nutrients in the media?

Metabolic capability testing

Using the genetic code (below), determine what type of mutation would occur if the last nucleotide in the codon AGA was converted to a U

Missense

Consider common human pathogens. Most of their enzymes likely function best under which of the following environmental conditions?

Moderate pH around 7 Temperature around 37 degrees C Low salt

The amino acid that is placed first during translation in bacteria, mitochondria, and chloroplasts is

N-formyl-methionine.

Identify which of the following are coenzymes.

NAD+ FAD NADP+

Cells are often ground up with abrasive to get to their internal enzymes/molecules, followed by removal of the abrasives. Here are three situations and three outcomes. What is the correct interpretation of the results? In situation #1, radioactive amino acids are added to cell material, and radioactive proteins are produced. In situation #2, radioactive amino acids, cell material, and the enzyme DNAse (degrades DNA) are added together. Radioactive proteins are still produced. In situation #3, the ground-up cell material is allowed to sit for 24 hours before radioactive amino acids and DNAse are added to it. No radioactive protein is produced. What is the most likely interpretation?

Natural RNAses present in the ground-up material will degrade any existing mRNAs in that 24-hour interval. Added DNAses break down DNA so that new RNAs are not synthesized. This will lead to a loss of capability to translate protein in the last scenario.

Intracellular Gram-negative diplococci found in a urethral sample from a male is indicative of

Neisseria gonorrhoeae

Which of the following pairs is NOT correctly matched?

Nonsense mutation—incorrect amino acid

DNA replication is

semiconservative

You have isolated a bacterium from a contaminated river but you are unable to culture it in the laboratory. Which method could you use to identify the organism?

Nucleic acid amplification tests

Which of the following is/are true of DNA replication?

Nucleotides are added to the 3' end

Select which of the following you think would be part of the traditional diet of the Inuit people.

Ocean fish Seal meat Caribou meat Whale meat

What would be the direct result of a bacterium losing the ability to produce DNA ligase?

Okazaki fragments could no longer be joined together

In prokaryotic DNA replication, which of the following is FALSE?

On one parent strand, the polymerase synthesizes DNA in the 5' to 3' direction, while on the other it synthesizes DNA in the 3' to 5' direction

When E. coli is placed in a medium containing both glucose and lactose, why does cell growth stop temporarily when the glucose is used up?

Once glucose is depleted, the cell must use the lactose; before it can do this, it must express the lac operon and synthesize the enzymes needed to use lactose, which takes time.

You are sent three clinical samples and are asked to determine whether they are the same strain. You perform standard identification techniques but cannot come to a conclusion. You decide to do an RFLP test. You digest the genomes of the organisms with the same restriction enzyme and run a gel. Each organism yields 5 bands on the gel, of the following sizes: Organism A: 3 kb, 7 kb, 11 kb; 14 kb, 21 kb; Organism B: 3 kb, 7 kb, 2 kb, 8 kb, 11 kb; Organism C: 11 kb, 3 kb, 14 kb, 7 kb; 21 kb What conclusion(s) can you make from this result?

Organisms A and C are likely the same strain but are different from organism B.

Organisms that grow very slowly, cannot be cultured, are present in very small numbers, or are mixed with a number of other bacteria may still be identified using

PCR

Every 24 hours, every genome in every cell of the human body is damaged 10,000 times or more. Given the possible DNA repair mechanisms, which order listed below would be most effective at repairing these as quickly as possible in order to prevent mutations from being carried forward in DNA replication?

Proofreading by DNA polymerase, glycosylase enzyme activities, excision repair, SOS repair

If Hershey and Chase had discovered at the end of their work that the bacteria that were radioactive were the ones that had been mixed with 35S-labeled phages, what would they have concluded?

Protein is the genetic material of a cell.

Why did scientists originally believe that genetic material was protein rather than DNA?

Proteins are more complex in structure than DNA; they thought DNA was too simple in structure to have such an important cellular role

A common environmental organism that may even grow in certain chemical disinfectants is

Pseudomonas aeruginosa

A soluble greenish pigment is produced by

Pseudomonas aeruginosa

What phenomenon is being illustrated in the figure below?

Quorum sensing

You have identified the causative organism of the outbreak as E. coli. In an effort to characterize the strain of the organism involved, you do different tests. The results are as follows: Gram stain—Gram-negative rods; Oxidase test—negative; Lactose fermentation—positive; Serological testing—O157:H7; Colony morphology—smooth, creamy colonies; RFLPs—E. coli O157:H7; Antibiogram—resistant to ampicillin. Which test(s) confirm the identity of the organism at the strain level?

RFLPs AND serological testing

Please select the FALSE definition regarding microbial identification.

RFLPs are patterns of fragment sizes obtained by digesting polypeptides with one or more proteases.

Your patient took biology many years ago. You remind her of the structure of DNA and RNA. Which statement is NOT correct?

RNA is a single-stranded molecule composed of nucleotides that contain the nucleobases adenine, thymine, uracil, or cytosine.

Which of the following is not involved in the initiation of translation?

RNA polymerase

Which would be most effective against Pseudomonas?

Radiation

Which word in the report means looking back at past events or situations?

Retrospective

Why are molecular methods particularly useful for identification of microbes that are difficult to grow?

Since all microbes have DNA, and we can often detect and identify them through even very small amounts of their DNA, molecular methods allow us to identify microbes even when they can't be grown at all.

Eventually Eduard Buchner showed that crushed (destroyed) yeast cells could convert sugar to ethanol and CO2. What did this experiment show?

Something was released from the crushed cells that could still convert sugar to alcohol.

Hexachlorophene has been particularly effective against

Staphylococcus aureus

The lab results indicate that the pus from your patient's "bite" contains clusters of spherical cells that stained purple in the Gram stain. You tell your patient that his wound contains bacteria from the genus ______ and is classified as a ______ organism.

Staphylococcus; Gram-positive

Assuming strict adherence to recommended protocols, which of the following achieves sterilization?

Steam autoclaving

Rank the germicides from most to least potent

Sterilants High-level disinfectants Intermediate-level disinfectants Low-level disinfectants

Gram-positive encapsulated diplococci found in sputum are likely

Streptococcus pneumoniae

One of the methods used to identify S. enterica in the lab is growth in tetrathionate broth, a selective enrichment medium for this organism. What does this mean?

Tetrathionate broth inhibits the growth of non-Salmonella bacteria and encourages the growth of Salmonella.

What was the hypothesis of the researchers in this report?

The Inuit people would have a more diverse gut microbiome than the comparison group

Your patient somewhat remembers the details of replication but can't really recall what role various enzymes play in the process. You give her the information. Which of the following would you NOT tell her?

The antiparallel strands of DNA are joined together by DNA ligase.

A sample must contain many microorganisms in order for them to be seen any using microscopy techniques. Why is this so?

The area on a microscope slide is very large compared to the relative size of microbes, and you take a very small amount of your sample to place on the slide surface. Therefore, you must have a large number of microbes initially in the culture to increase the chances that you'll be able to see bacteria on the slide.

Your patient asks why the penicillin he has been taking hasn't helped his infection. Which of the following is a possible explanation for your patient?

The bacteria causing the infection are resistant to penicillin; a different antibiotic is needed.

You mix two bacterial stains in a tube of glucose-salts agar. One strain is His−, Val−, while the other strain is Trp−, Leu−. You previously showed that neither strain grows on glucose-salts agar. After incubating the tube, you plate a sample onto a new glucose-salts agar plate. Several colonies grow. What do you know is TRUE about these colonies?

The bacteria in the colonies are His+, Val+, Trp+, Leu+

In direct selection methods used to identify possible carcinogens (example: Ames testing), what does it mean when a chemical can cause a bacterium to develop resistance to some environmental condition?

The chemical is a mutagen

What happens to the protons received from NADH in bacteria?

They are transported across the cytoplasmic membrane, setting up a proton motive force.

To which part of a DNA molecule are nucleotides added?

The hydroxyl group on the 3' end of the molecule.

Cells are often ground up with abrasive to get to their internal enzymes/molecules, followed by removal of the abrasives. Here are two situations and two outcomes. What is the correct interpretation of the results? In situation #1, radioactive amino acids are mixed with ground-up cell material. Radioactive proteins are produced. In situation #2, radioactive amino acids AND the enzyme RNAse (an enzyme that degrades RNA) are mixed with ground-up cell material. No radioactive proteins are produced.

The mRNA from the cell can be used to make proteins with the radioactive amino acids in the first situation. In the second situation, the mRNA is destroyed by the RNAse before it can be translated into protein containing the radioactive amino acids.

A hydrogen atom consists of

a proton and an electron

When bacteria such as S. enterica infect the intestinal tract, inflammation results. This is one of the body's immune defenses. Researchers have recently discovered that tetrathionate is produced in the intestinal tract as a result of inflammation. Why is this important?

The presence of tetrathionate gives the Salmonella a competitive advantage over the normal microbiota such as E. coli.

When DNA probes are used to identify bacterial DNA similarities by hybridization, the probe DNA is heated and the template DNA is treated to separate the two strands. Why would the probe DNA be heated?

The probe may contain parts that are double-stranded. Heating it up breaks the hydrogen bonds holding the strands together, creating single-stranded sequences that hybridize with their complementary targets.

You make two agar plates: one is a nutrient agar plate (plate A) that contains histidine and penicillin. The other is a glucose salts agar (plate B) that also contains penicillin. You inoculate a sample onto both plates using replica plating technique, incubate the plates, and compare the growth after 48 hours. There are 12 colonies on the nutrient agar plate and 11 colonies on the glucose salts medium. Which of the following statements is INCORRECT?

The prototrophs are resistant to penicillin but the auxotrophs are sensitive to this antibiotic

When setting up the reaction in tube 1, you measure the rate of product (brown pigment) formation upon adding the catechol substrate. If you set up another tube but instead add twice the amount of substrate, what do you think would be the effect on the rate of product (brown pigment) formation compared to the first test tube? Assume that the enzyme is not saturated with substrate.

The rate of the second tube would be faster than that of the first tube

Which of the following is a possible explanation for the lack of diversity in the Inuit gut microbiome?

The traditional Inuit diet lacks fresh fruit and vegetables, and thus fiber, leading to less a diverse gut microbiome.

How might the MRSA strain become resistant to vancomycin?

The transposon from the E. faecalis "jumped" into the MRSA plasmid.

Which is true of nosocomial infections?

They are acquired by susceptible people in the hospital

Which of the following is FALSE about transposons?

They are capable of moving independently from one cell to another cell.

Hershey and Chase labeled virus DNA and protein using radioactive isotopes. What does this mean?

They grew the viruses in medium containing radioactive elements (in this case S or P) so that components of the virus containing those elements would have a radioactive tag and be detectable.

Some bacteria have a higher incidence rate of thymine dimer mutations following exposure to UV light than others. What might be going on here to lead to this outcome?

They may simply have a higher proportion of T nucleotides next to each other in their DNA than other bacteria, leading to more possible dimers being formed AND they may have a WEAKER expression of photoreactivation enzymes, leading to formation of more thymine dimers.

Why did the laboratory technicians use the aerobic culture of the patient's knee fluid for their identification tests?

They only had an aerobic reference panel for their AMIS

Which of the following about transposons is not true?

They were first recognized in fungi.

Preventing the function of light repair (photoreactivation) interferes with the repair of which of the following?

Thymine dimers

Which of the following is INCORRECT?

Transcription is the conversion of DNA into RNA.

Which of the following statements concerning transcription and translation in eukaryotes is TRUE?

Transcription occurs in the nucleus and translation occurs in the cytoplasm

Which of the following statements is CORRECT regarding transformation?

Transformation is the uptake of "naked" DNA from the environment

T/F: Boiling is very effective at removing most common waterborne pathogens.

True

If a DNA triplet is AGT, the mRNA codon would be ______ and the tRNA anticodon would be ______.

UCA; AGU

Which of the following is an acronym for a type of infection given in the report?

UTI

Which of the following methods sterilize the materials?

Ultrahigh-temperature (UHT) method

Your brother tells you that most likely you ingested Giardia cysts that were in the stream water. He says you should have treated the water before you drank it. Which of the following would NOT have been a possible way for you to do this, as a hiker?

Using high pressure processing.

In prokaryotic cells undergoing respiration, protons are pumped

from inside the cell to outside the cytoplasmic membrane

Which of the following destroys acellular infectious agents?

Virucides

What conclusion can you make from the data* presented?

Washing your hands with water removes some bacteria, but adding soap is more effective.

Review the chart showing hypothetical data for a similar case. The purple line represents VRSA. The orange line shows VSSA (vancomycin-sensitive S. aureus). After how many days of vancomycin treatment is VSSA completely eliminated?

We are not given this information

Why would it be beneficial for cells to wait until a critical population density is reached before expressing certain genes?

Without a certain density, it would be highly unlikely that the molecules produced by a cell in the group could find and bind to other cells of the population effectively.

A mutation in E. coli results in the loss of both restriction endonucleases and modification enzymes. Would you expect any difference in the frequency of gene transfer via transduction FROM Salmonella INTO this E. coli strain?

Yes—the loss of the restriction endonucleases would leave the recipient E. coli unable to break down "invading" viral DNA from the transducing phage, AND the loss of the modification enzymes would leave the recipient E. coli unable to tag its own DNA as "self," leaving the viral DNA untagged and recognizable as "foreign," and targeted for destruction. Together, these would lead to higher rates of successful transduction. (longest)

The study of the crown gall tumor found

a bacterial plasmid promoter that was similar to plant promoters

Hfr refers to

a cell in which the F plasmid has been integrated into the cell chromosome

For synthesis of an inducible enzyme to occur,

a compound must bind to the repressor

In a MALDI-TOF assay,

a microorganism's proteins are separated and sorted by mass to generate a profile that provides a fast way to identify a colony

Intercalating agents

act during DNA synthesis AND often result in frameshift mutations

In the absence of lactose, the lac repressor is

active and can bind to the operator

The rate of growth in flask 3 is substantially faster than that in flask 1 and somewhat faster than that in flask 2. The E. coli in this tube can be most accurately described as undergoing ______.

aerobic respiration

The largest group of chemical mutagens consists of

alkylating agents

Which of the following is (are) considered when selecting a germicidal chemical?

all (Toxicity AND cost, Cost AND compatibility with the material being treated, Compatibility with the material being treated AND environmental impact, Environmental impact, toxicity AND cost)

A sterile item is free of

all viable microbes, endospores, AND viruses

A selective growth medium

allows only certain bacteria to grow

Phase variation is a phenomenon used by some bacteria (such as E. coli) to evade host immune mechanisms. In this process, the cells

alternately turn genes on/off to adjust bacterial behavior

In conjugation the donor cell is recognized by the presence of

an F plasmid

A culture of E. coli is growing on glucose salts agar (GSA), a chemically defined medium that contains glucose as its sole carbon source. E. coli utilizes the glucose for both its energy and carbon needs. During metabolism, it uses precursor metabolites of its central metabolic pathways and ATP to build up the biological macromolecules needed to make cell components. These biosynthetic reactions are best described as ______.

anabolism

The rate of growth in flask 2 is substantially faster than that in flask 1, but somewhat slower than that in flask 3. You detect the production of nitrite. The E. coli in this tube can be most accurately described as undergoing ______.

anaerobic respiration

As bacteria grow in broth, oxygen becomes depleted. At that point, most bacteria switch to fermentation to continue growing. In tetrathionate broth however, S. enterica can switch to anaerobic respiration. This gives the organism a growth advantage because

anaerobic respiration yields more ATP per glucose molecule than fermentation.

You patient tells you he has heard that N. gonorrhoeae is increasingly difficult to treat because of resistance to antibiotics. He asks whether it is possible to determine which antibiotics will be affective in treating his infection. You tell him that ______ indicate antibiotic susceptibility.

antibiograms

Changing your T-shirt for one of a different color is analogous to ______.

antigenic variation

Neisseria gonorrhoeae has the ability to randomly express different genes coding for pilin, the protein making up pili. This makes it difficult for the body's immune system to mount a response to the pathogen—it will start to respond to the first type of pilin made, but some bacterial cells then begin to express a different type of pilin, and those bacteria avoid the immune defenses and survive. This is an example of ______.

antigenic variation

Your patient tells you she didn't get the flu vaccine either because she heard that she would have to get it every year. She doesn't understand why this is that case. You explain that flu viruses have two types of glycoprotein spikes that have a role in flu virus pathogenesis. Every year, minor changes occur in the genes that code for these spikes, resulting in slight changes in their amino acid sequence. These changes to the spikes on the surface of the virus is an example of ______.

antigenic variation

Competent cells

are able to take up naked DNA, occur naturally AND can be created in the laboratory.

Activators

are allosteric proteins AND are involved in positive control

The Ames test is useful as a rapid screening test to identify those compounds that

are mutagens

Ribozymes

are self-catalytic RNA AND suggest that nucleic acids evolved before proteins

Insertion sequences

are the simplest type of transposon, code for a transposase enzyme, AND are characterized by an inverted repeat

Serological methods

are useful in identifying bacteria

Human DNA cut with restriction enzyme A can be joined to

bacterial DNA cut with restriction enzyme A

Chemical mutagens that mimic the naturally occurring bases are called

base analogs

You tell your patient that the genetic code is used when translating mRNA to synthesize protein. You explain that the code is degenerate and that this is important because

base-pairing errors made during transcription may not result in a change in the encoded protein.

Streptococcus pyogenes would be

beta hemolytic AND catalase negative

Repressors

bind or do not bind to the operator depending on their shape (conformation) AND are involved in negative control.

Negative control means a regulator molecule is

bound, and transcription is inhibited OR removed, and transcription starts

Gamma irradiation

can be used to either sterilize or pasteurize, depending on the dose of radiation

Antigenic variation is a phenomenon used by some bacteria (such as Neisseria gonorrhoeae) to evade host immune mechanisms. In this process, the cells

can change the characteristics of certain surface proteins on the bacteria, forcing immune response to constantly adapt

One of the first chemicals used by Lister to prevent surgical infections was

carbolic acid

A culture of bacteria is breaking down sugars to yield energy. This is best described as ______.

catabolism

An organism produces bubbles upon addition of hydrogen peroxide and causes the pH of the medium to become very acidic when grown in the presence of lactose. This organism is

catalase-positive and can ferment lactose

Quaternary ammonium compounds are

cationic detergents that help wash surfaces

X-rays

cause breaks in DNA molecules

The synthesis of ATP via ATP synthase, driven by a proton motive force, is called ______.

chemiosmosis

AUG

codes for methionine AND determines the reading frame

A stop codon

codes for no amino acid.

To reduce or eliminate disease-/spoilage-causing organisms, food is often subjected to

cold, heat, radiation, chemical additives -all of the above

Your patient asks what other types of tests are available for identifying N. gonorrhoeae. You tell him that the organism is fastidious, oxidizes only glucose as a carbohydrate source, breaks down H2O2, exhibits cytochrome c oxidase activity, is resistant to the antibiotic colistin, and produces at least four different colony types. Based on this, which of the following would you NOT use for characterization of this pathogen?

colony morphology

APITM, EnterotubeTM, and VitekTM are all

commercially available methods used to identify bacteria

Modern approaches to evolutionary taxonomy often involve

comparison of DNA or RNA

Not all bacteria can take up DNA from the environment. Those that can are referred to as

competent

The placement of the amino acid during translation is determined by the

complementarity of the codon-anticodon

Gene transfer that requires cell-to-cell contact is

conjugation

The transfer of vancomycin resistance from Enterococcus faecalis to Staphylococcus aureus is thought to have involved

conjugation AND transposons

UV light and other non-ionizing radiation damage DNA molecules by

creating thymine dimers between adjacent thymine nucleobases in the DNA chain

In prokaryotic cells, the electron transport chain (ETC) is located in the ______, whereas in eukaryotic cells, the ETC is located in the ______.

cytoplasmic membrane; inner membrane of mitochondria

Phenolics

denature proteins and destroy cytoplasmic membranes

Moist heat primarily destroys microbes by

denaturing their proteins

Commercial canning processes

destroy Clostridium botulinum spores, are especially needed on low acid foods, AND are 12D processes (designed to kill 1012 endospores).

Sequencing of rRNA is useful for

determining evolutionary relationships AND identification of unknown bacteria

Upon treatment with heat or chemicals, bacteria will

die at a constant proportion

Bacterial cells that have been genetically modified to carry an antibiotic resistance gene can be separated from susceptible (non-resistant) microbes by using a ______ selection method using agar plates with antibiotic.

direct

Chlorine has traditionally been used to disinfect water, preventing the spread of waterborne illnesses. However, chlorine (and other disinfectants) can react with naturally occurring water chemicals, forming ______, which can have long-term health risks.

disinfection by-products (DBP's)

Organize the following taxonomic categories from the most inclusive to the least inclusive. (high to low)

domain, kingdom, phylus, class, order, family, genus, species

Generally, membrane filters are not used to remove

enzymes from liquids

RNA interference (RNAi) is a mechanism by which

eukaryotic cells destroy RNA transcripts in a selective and specific manner to control gene expression.

After conjugation of an Hfr cell and an F- cell, the entire genome of the Hfr cell is usually transferred to the recipient cell.

false

Chemical agents can cause mutations by inducing ethylation of guanine residues in DNA

false

DNA fingerprinting is a method of identification based on amino acid sequence analysis.

false

Despite the fact that you are certain that your patient has gonorrhea based on the Gram stain results, it is essential to confirm your diagnosis by 16S rRNA sequencing.

false

If each of two bacteria have a GC content of 50%, they are both definitely closely related.

false

Restriction enzymes cut only at specific sites and therefore are not useful for microbial identification.

false

Review the chart showing hypothetical data for a similar case. The purple line represents VRSA. The orange line shows VSSA (vancomycin-sensitive S. aureus). A concentration of greater than 0.02 mg/mL of vancomycin is sufficient to inhibit the growth of VRSA.

false

Strain A is different from Strain B but identical to Strain C

false

T/F: 100% ethanol is twice as effective as 60% ethanol at controlling bacteria

false

T/F: A codon consists of two nucleotides.

false

T/F: A missense mutation has a greater impact on a cell than does a frameshift mutation.

false

T/F: A traditional diet is always plant-based and rich in fiber

false

T/F: A transposon always causes a mutation.

false

T/F: Adenine binds to thymine via three hydrogen bonds.

false

T/F: All biochemical pathways have the same number of enzymatic reactions.

false

T/F: All mutagens are carcinogens but not all carcinogens are mutagens.

false

T/F: An enzyme can only bind one substrate at a time.

false

T/F: An enzyme speeds up a chemical reaction in the cell, but can only be used once.

false

T/F: Cold and freezing are very effective in killing bacteria

false

T/F: DNA replication is usually unidirectional.

false

T/F: Double-stranded DNA enters the recipient cell during transformation.

false

T/F: Dry heat takes a much shorter time to sterilize material than wet heat.

false

T/F: Gram staining is never sufficient for diagnosis

false

T/F: Handwashing with regular soap removes all normal microbiota from the skin.

false

T/F: Heat treatment is an effective method for sterilization or disinfection of all materials

false

T/F: Hydrogen peroxide may be used as a sterilant on living tissue

false

T/F: In multilocus sequence typing (MLST), the sequences of all ribosomal subunits of an organism are determined and compared to those of other organisms.

false

T/F: Measures to prevent prion contamination of healthcare settings have been in place for the past several decades and fully control the risk.

false

T/F: Microwaves kill microorganisms directly

false

T/F: Most people who get Salmonella contract it from turtles.

false

In eukaryotic cells undergoing respiration, protons are pumped

from the mitochondrial matrix to the intermembrane space

T/F: One of the genes affected in Diamond-Blackfan Anemia is called RPS19. This gene plays a role in maturation of the 40S subunit. Your sister tells you she heard that protein synthesis can occur normally if the large ribosomal subunit is present, even if the small subunit is not because the large subunit is the part that decodes the information. You tell her that this is

false

T/F: Organisms termed his- are considered prototrophic for histidine.

false

T/F: Pasteurization results in the sterilization of food products

false

T/F: Prions are easily destroyed by common sterilization procedures

false

T/F: Serratia marcescens are red when incubated at 37°C.

false

T/F: Sterilization is the destruction of all living microbes from a surface by physical or chemical means

false

T/F: Strains of an organism can always reliably be identified using RFLPs (restriction fragment length polymorphisms).

false

T/F: Streptococcus pyogenes can be easily distinguished microscopically from other Streptococcus species.

false

T/F: The cytoplasmic membrane is permeable to protons

false

T/F: The endospores of Pseudomonas make that organism very difficult to kill

false

T/F: The location of the photosynthetic pigments that form photosystems is the stroma of the chloroplast.

false

T/F: The most difficult aspect of the new field of metagenomics is generating sequence data reliably and cost-effectively.

false

T/F: The plus (+) strand of DNA acts as a template during transcription.

false

T/F: When the CDC examined water samples from Practice A, they found 91,333 M. abscessus cells per milliliter of water.

false

The entire genome of the donor cell is usually transferred to the recipient cell.

false

The enzyme ethylguanine-DNA ethyltransferase prevents DNA mutations from occurring.

false

The only way for the VRE to be transferred from the patient's catheter site to her foot ulcer would be by a healthcare worker who did not follow proper protocol.

false

The patient's bacteremia was caused by VRSA.

false

To isolate a His- mutant, the researcher need only inoculate the bacteria onto nutrient agar containing histidine.

false

Transposons are composed of amino acids.

false

V. parvula is an aerobe.

false

Streptococcus pneumoniae lacks an electron transport chain. Therefore, S. pneumoniae generates ATP via ______.

fermentation

The rate of growth in flask 1 is slower than that in flasks 2 and 3, and you detect the production of lactic acid. The E. coli in this tube can be most accurately described as undergoing ______.

fermentation

The high-energy electrons of photosystem I are directly passed on to ______.

ferredoxin

What is the number of tRNA molecules that may be associated with translation?

fewer than 64

Post-translational modification may include

folding of the protein, often with the aid of chaperones, AND removal of the signal sequence.

A culture of E. coli is irradiated with UV light. The UV light affects the cell's DNA by

forming covalent bonds between thymine bases on the same strand of DNA.

Following digestion with restriction enzymes, DNA fragments are separated according to size by ______.

gel electrophoresis

Bacteria that have properties of both the donor and recipient cells are the result of

genetic recombination

Phylogenetic relationships between prokaryotes are most accurately determined using

genotypic information

The simultaneous regulation of many bacterial genes is

global control

The lac operon is expressed when

glucose is low and lactose is present

When polysaccharides are broken down, their breakdown products can be oxidized for energy by entering which of the following metabolic pathways?

glycolysis

Review the chart*. Which bar(s) represent(s) the control in this experiment?

green

To increase the chance of detecting carcinogens in the Ames test, the test substance is treated with

ground-up rat liver

Which of the following can be used to make drinking water safe? Check all that apply.

halogens ozone

The 3' end of DNA

has a hydroxyl group attached to the number 3 carbon of deoxyribose

Boiling is not reliable for sterilization because

heat-resistant endospores are unaffected

The autoclave treatment may be monitored by

heat-sensitive tape AND heat-resistant endospores of Geobacillus stearothermophilus.

From reading this case, you know that

hepatitis C is caused by a virus

Cells that are His-, StrR could be isolated from a mixed sample by using a medium containing

histidine AND streptomycin

Disagreements between conclusions obtained from rRNA data and other techniques may be explained by

horizontal DNA transfer

The name Lactococcus (Streptococcus) lactis

indicates that Streptococcus is the old genus name

The molecules that bind to a repressor and cause it to no longer bind to the operator are called

inducers

The lac operon is ______.

inducible

The most important function of nitrites in processed foods is to

inhibit the germination of Clostridium botulinum endospores

Your patient asks whether there is any way for him to get rid of this infection. You tell him that he will be given a different antibiotic such as doxycycline. This antibiotic works by binding to a cell structure called the 30S ribosomal subunit, which stops the bacterial cells from growing by

inhibiting protein synthesis

A fundamental aspect of gene regulation lies in the ______ of mRNA molecules. Because of this trait, these molecules won't remain in the cell long after transcription has been turned off by the cell, regulating gene expression.

instability

The clustered, regularly interspaced short palindromic repeats (CRISPR) system in bacterial cells has been called the "immune" system of bacteria. CRISPR protect bacteria from a repeat infection from the same phage because bacterial cells

integrate fragments from the phage DNA in their own chromosomes and target for destruction any DNA that contains the same fragments in the future

Hfr refers to a cell that has

integrated the F plasmid into its genome.

Planar molecules used as chemical mutagens are called

intercalating agents

Some segments of the precursor mRNA in eukaryotes are non-coding and are called

introns

Among the easiest of the mutations to isolate are those which

involve haploid chromosomes AND involve antibiotic resistance

Quorum sensing

involves the production and monitoring of signaling molecules AND is used by bacteria to sense the density of cells within their population.

Moist heat kills microorganisms by

irreversible denaturation of proteins

Mycobacterium tuberculosis is one of the few species of bacteria that

is acid-fast

The relatedness of organisms determined by counting common characteristics

is called numerical taxonomy

Chlorhexidine

is extensively used in antiseptics

The lagging strand

is formed during DNA replication because of the antiparallel nature of DNA.

If a protein-encoding gene contains introns and exons, it is likely that

it is a eukaryotic gene

Hand washing with plain soap is very effective in controlling spread of microorganisms because

it is very effective at the mechanical removal of microorganisms

Boiling is not a reliable method for sterilization because

its does not destroy heat resistant endospores

What part of the body is affected with hepatitis?

liver

Ribosomes are involved in generating proteins in a cell. The other components directly needed for this process to occur are

mRNA, tRNA, and amino acids

Phenotypically identical bacteria

may be told apart by DNA sequence analysis

Various strains of E. coli

may cause disease AND may be harmless

The regulatory protein

may inhibit or enhance transcription

Liquid media containing heat-sensitive components would best be sterilized by

membrane filtration

Select the method that would be used to sterilize a liquid containing vitamin B12 and human growth hormone

membrane filtration

DNA is protected from restriction enzymes by being

methylated

The ribosomes

move along the mRNA in a 5'-3' direction AND provide a platform that brings the amino acids into a favorable position for joining.

In bacteria, proton pumps are protein complexes that

move protons from the interior of the cell to the exterior

The source of variation among microorganisms that were once identical is

mutation

If Gene X codes for an F pilus and transposition occurs, then the bacterium containing the plasmid would

no longer be able to conjugate

Alcohols are not reliably effective at destroying

non-enveloped viruses AND endospores

Your sister asks you what the difference is between protein synthesis and translation. You explain to your sister that the process of generating proteins in a cell is called translation because the information for the protein is in the form of ______ but proteins are composed of _____.

nucleic acids; amino acids

A culture of E. coli is irradiated with UV light. The highest frequency of mutations would be obtained if after the irradiation, the cells were immediately

placed in the dark

Consider the biochemical pathway: A → B → C Enzyme 1 catalyzes A → B Enzyme 2 catalyzes B → C Enzyme 1 can use

only A as a substrate

The DNA site to which the repressor protein binds is the

operator

The set of genes in bacteria that are linked together and transcribed as a single unit is referred to as a(n)

operon

If the GC content of two organisms is 60%, the

organisms are most likely related

Cells obtain energy by ______ food molecules such as glucose.

oxidizing

__________is a brief heat treatment that reduces the number of spoilage organisms and destroys pathogens. It can be used on foods or inanimate objects.

pasteurization

To increase the proportion of auxotrophic mutants in a population of bacteria, one may use

penicillin enrichment

To isolate penicillin-resistant mutants, the scientist must inoculate the parent population on plates containing ______; this approach is ______ selection.

penicillin; direct

You tell the patient that his sample contains white blood cells in which Gram-negative diplococci can be detected. Your patient asks how you obtained this result and you tell him you

performed a Gram stain

H. influenzae has genes that it needs to make pili for attachment to host cells. These pili genes are not always expressed; sometimes the bacterium turns them off and does not produce pili. This is an example of

phase variation

The characteristics displayed by an organism in any given environment is its

phenotype

The properties of a cell that are determined by its DNA composition are its

phenotype

Colonies of the bacterium Serratia marcescens are red when incubated at 22°C but white when incubated at 37°C. This is an example of

phenotypic change

Anabaena is a genus of filamentous cyanobacteria commonly found in aquatic environments, where it harvests energy from sunlight and fixes both carbon dioxide and nitrogen. Knowing this, how would you classify Anabaena?

photoautotroph

In 1908 Orla-Jensen suggested that bacteria be grouped according to their

physiology

In the 1930s Kluyver and van Niel proposed a classification scheme based on

presumed evolutionary relationships

Silver sulfadiazine, a combination of silver and a sulfa drug, is used to

prevent infection of second- and third-degree burns

Removing the electron transport chain of E. coli would

prevent oxidative phosphorylation

The figure below shows gene expression in

prokaryotes

The specific sequence of nucleotides in the DNA to which the RNA polymerase binds is the

promoter region

You explain that transcription starts at a particular region on the DNA template called the ______, and ends at a sequence called the ______.

promoter; terminator

Transcription begins at the ______ and ends at the ______, while translation begins at the ______ and ends at the ______.

promoter; terminator; start codon; stop codon

You explain to your sister that ribosomes are the site of ______ in cells.

protein synthesis

Enzymes are usually ______.

proteins

Antibiotics

provide an environment in which preexisting mutants survive

Which molecule was the basis for establishing the three-domain classification system?

rRNA

In the method shown in the figure, the probes used in detecting the nucleic acid sequences can be labeled with a

radioisotope or fluorescent dye

Chlorine

readily reacts with organics to produce potentially carcinogenic trihalomethanes

The genetic code has more than one codon for some amino acids. This is an example of

redundancy

Operon(s) in bacteria

refers to a group of genes that are controlled in a coordinated manner AND involve polycistronic mRNA.

The term antiparallel

refers to the opposite orientation of the two strands in DNA.

Transcription is often controlled by DNA-binding proteins. A(n) ______ is a regulatory protein that blocks transcription, while a(n) ______ is a regulatory protein that facilitates transcription.

repressor; activator

In DNA fingerprinting, the DNA that has been collected is cut into smaller pieces by ______.

restriction enzymes

The transcription terminator

results in a hairpin loop structure in RNA, AND results in the polymerase falling off the DNA template.

Transposons are

segments of DNA

In the name E.coli O157:H7; "O157:H7" refers to the ______ of the organism.

serotype

An early attempt by Cohn at bacterial classification grouped bacteria according to their

shape

Bacteria use ______ attached to the polymerase to direct RNA polymerase to promoters; eukaryotic cells use ______ that attach directly to the DNA first instead.

sigma factors; transcription factors

Based on the Gram stain results, you tell your patient that you think he has gonorrhea, a sexually transmitted infection (STI) caused by the bacterium Neisseria gonorrhoeae. You are able to make this diagnosis based on

signs and symptoms AND because N. gonorrhoeae is the only Gram-negative diplococcus found within white blood cells in the male urethra

The DNA of the unknown organism must be denatured to allow

single strand complimentary probes bind to the unknown DNA

Genes from the donor chromosome are transferred as

single stranded DNA

What structure is indicated by: 10A, 15T, 3G, 7C?

single stranded DNA

During conjugation, the donor chromosome is transferred as

single-stranded DNA

In transformation, genes from a donor chromosome are transferred as

single-stranded DNA

In higher organisms, successful mating can occur between members of the same

species

The basic taxonomic unit in the classification scheme of plants and animals is

species

Further tests indicate that your patient has a methicillin-resistant Staphylococcus aureus (MRSA) infection. You explain to the patient that these bacteria are not impacted by penicillin or the related drug methicillin. This resistance is thought to have arisen originally by a random change in the cell's chromosome through a process called

spontaneous mutation

In translation, the codon at which the process begins is called the ______ codon, while the codon at which the process ends is called the ______ codon.

start; stop

The process of killing or removing all of the microorganisms in or on a material is called

sterilization

A common application of dry heat in the microbiology laboratory is to

sterilize the inoculating loop

The Calvin Cycle takes place in the ______ of chloroplasts.

stroma

Which of the following binds to the active site of an enzyme?

substrate

A DNA similarity of 75% between two organisms

suggests the organisms are closely related at the species level

Which molecule carries an anticodon?

tRNA

Direct selection involves inoculating cells onto growth media on/in which

the mutant but not the parental cell type will grow

Jasmine tells you she plans to wash her hands with soap and water before working on Paul's boil, to get rid of all the bacteria on her skin and prevent the possibility of Paul getting an infection. You tell her

that washing and scrubbing with soap is generally sufficient to control microbes in routine situations but that soap itself does not destroy many organisms. Jasmine should try to get some sterile gloves.

All of the following are true about DNA sequence analysis EXCEPT

the (−) strand of DNA is used.

When looking at the GC (or G + C) content, a researcher is studying

the DNA of the organism

When E. coli is grown in medium containing both glucose and lactose,

the cells grow fastest initially when glucose is available

These dimers are repaired by

the enzyme DNA photolyase and exposure to light

In the electron transport chain, protons are pumped across the cell membrane. This results in

the formation of a proton motive force

The designation his- refers to

the genotype of a bacterium that lacks a functional gene for histidine synthesis AND bacteria that are auxotrophic for histidine.

Microwaves do not kill organisms directly but kill by

the heat they generate in a product

The diploid character of eukaryotic cells may mask the appearance of a mutation since

the matching chromosome may carry the correct version of the gene

The more closely related two organisms are,

the more similar their nucleic acid sequence

After the conjugation of an Hfr cell with an F- cell,

the recipient remains F-

The F plasmid carries the information for

the sex pilus

When filtering a liquid, it is a bad idea to use a membrane with a pore size smaller than necessary because

the smaller the pore size, the slower the filtration process, so you would be wasting time

In E. coli O157:H7, the O157:H7 refers to the

the specific LPS and flagella type present

In aerobic respiration, oxygen acts as

the terminal electron acceptor

Compounds of tin, mercury, arsenic, and copper are no longer used to prevent microbial growth in cooling water primarily because

their use contributes to serious pollution of natural waters

In the figure, the probes in A do not bind to the denatured DNA because

they are not complementary to the unknown DNA

If the GC content of two organisms is 45% in both,

they may or may not be related

PCR reactions are carried out in machines called thermocyclers.

true

Salmonella and Shigella bacteria should generate different DNA fingerprints.

true

T/F: A probe is a single-stranded piece of nucleic acid labeled with a detectable marker, used to locate a unique nucleotide sequence that identifies a particular microbial species.

true

T/F: All known species of bacteria are described in Bergey's Manual of Systematic Bacteriology.

true

T/F: Antisense RNA is the complement of the plus strand and may be useful in inhibiting translation.

true

The codon ACA encodes ______.

threonine

Irradiation of cells with ultraviolet light may cause

thymine dimers

Metagenomics is the analysis of

total microbial genomes in an environment

Strain differences are helpful in

tracing the source of outbreaks of disease

An alternative sigma factor would directly affect which process?

transcription

In order for a cell to make ribosomes, which of the following must be happening?

transcription and translation

You give your patient some general information on gene expression in cells. You explain that when cells divide, two processes are involved: replication and gene expression. Gene expression includes two related events: (i) copying the information encoded in DNA into RNA, a process called ______, followed by (ii) the interpretation of the information carried by the RNA to synthesize the encoded protein in a process called ______.

transcription; translation

The mechanism by which genes are transferred into bacteria via viruses is called

transduction

What concerns you most about the strain of H. influenzae that you may be exposed to while you are away is antibiotic resistance. The genes for resistance can be acquired by this organism as naked DNA from the environment, an example of

transformation

Which of the following requires that cells be competent?

transformation

You explain to your patient that there has been an increase in the number of strains of S. aureus that are now resistant to methicillin. The gene conferring resistance has moved from one strain to another via mobile gene elements, an example of which is a(n) ______.

transposon

Segments of DNA capable of moving from one area in the DNA to another are called

transposons

You remind your patient that information for proteins is encoded in DNA ______. These are copied into ______ in the mRNA.

triplets; codons

A transposon can move from the host chromosomal DNA to a plasmid.

true

At the end of your conversation with Jasmine, you tell her that the best course of action for her and Paul is to go to the clinic and have the boil treated there. A boil is a serious infection and the risks of trying to treat it at home are just too great.

true

Following base removal, DNA polymerase can add nucleotides in the 5' to 3' direction.

true

Improper base-pairing during DNA replication causes a pause in chain elongation.

true

In this case, a person who contracted Salmonella from a turtle was classified as having a primary infection. A person who acquired Salmonella by person-to-person transmission from a person with a primary infection would be classified as having a secondary infection.

true

T/F: You isolate a prokaryote. After performing analysis on the organism, you cannot find a description matching that of your organism in the reference text Bergey's Manual of Systematic Bacteriology. This suggests that you have likely isolated a new organism.

true

T/F: rRNA sequence comparisons are useful for determining evolutionary relationships

true

The donor cell DNA is integrated into the recipient cell's DNA by homologous recombination.

true

The hospital acted appropriately when they alerted the Idaho Bureau of Laboratories after they identified F. tularensis, and also placed all personnel who had come into contact with the bacteria onto prophylactic antibiotics.

true

The restriction-modification system always has two genes involved, the cutting enzyme and the methylating enzyme

true

The three domain systems consist of Archaea, Bacteria, and Eukarya.

true

True of False: The encoded protein of the DNA sequence 3' TAC CGC TTA CAT GAG 5' (assume it is the minus strand) has the amino acid sequence met-ala-asn-val-leu. Use the genetic code below.

true

What is a synonym for the word "employed" which we see in this sentence: Pasteur studied the relationship between yeast and alcohol production using a strategy commonly employed by scientists today?

used

Nucleic acid techniques have great power as diagnostic tools because they may be

used to differentiate species

RNAi

uses short pieces of single-stranded RNA to direct the degradation of specific RNA transcripts

Media that change color as a result of the biochemical activity of growing bacteria

usually contain a pH indicator

Woese

was involved in determining rRNA sequences AND proposed breaking prokaryotes into two groups

The electrons excited by photons of light are replaced by electrons from ______ in photosystem II, and by electrons from ______ in photosystem I.

water; photosystem II

You ask your brother which method of eliminating microbes is the best in general. He tells you that there is no one perfect method and that various factors must be taken into account when considering any antimicrobial approach. These include all of the following EXCEPT

whether a potential infection can be easily treated.

In order for insertional inactivation to occur, the transposon must be placed

within the gene in question

A drug that inhibits the activity of bacterial DNA gyrase ______ be a good antibiotic because ______.

would; it would selectively inhibit bacterial DNA synthesis due to differences between bacterial/human gyrase