Exam 3

Place the various organisms in order from most resistant to least resistant to antimicrobial agents. Drag the appropriate labels to their respective targets.

Prions Bacterial Endospores Cysts of Cryptosporidium (protozoan) Mycobacteria Cysts of other protozoa Small nonenveloped viruses Active-stage protozoa (trophozoites) Fungal spores Most Gram-negative bacteria Vegetative fungi Large noneveloped viruses Most Gram-positive bacteria Enveloped viruses

What are the products of semiconservative replication for a double-stranded DNA molecule? Two double-stranded DNA molecules, one consisting of two parental strands and the other consisting of two daughter strands. One double-stranded DNA molecule, consisting of two daughter strands. One double-stranded DNA molecule consisting of one parental strand and one daughter strand. Two double-stranded DNA molecules, each consisting of one parental strand and one daughter strand.

Two double-stranded DNA molecules, each consisting of one parental strand and one daughter strand.

During the initiation step of translation, the fMet charged tRNA assembles in which site of the ribosome? A site P site E site

P site

The tRNA molecule holding a growing polypeptide chain is at the _____. 50S site A site P site E site

P site

Which category of antimicrobial drug works by changing the shape of a ribosome? oxazolidinones tetracyclines aminoglycosides chloramphenicol

aminoglycosides

Which antimicrobial drugs affect the structure of the ribosome itself? aminoglycosides, antisense nucleic acids, and oxazolidinones aminoglycosides, chloramphenicol, and lincosamides macrolides and antisense nucleic acids tetracyclines and oxazolidinones

aminoglycosides, antisense nucleic acids, and oxazolidinones

How did the multi-drug-resistant strains of Mycobacterium tuberculosis, like those in the prison, arise? point mutation frameshift mutation conjugation and exchange of resistance factors located on plasmids inclusion of histidine in the patient's diet

conjugation and exchange of resistance factors located on plasmids

A transducing phage contains fragments of the host chromosome instead of the viral genome. cannot infect new host cells. is a lysogenic bacteriophage. has a viral coat made of host proteins.

contains fragments of the host chromosome instead of the viral genome.

Which of the following is NOT used by bacteria to acquire new genetic material? conjugation transduction transformation crossing over

crossing over

Which of the following could be used to sterilize objects such as medical devices? silver nitrate orthophenylphenol ethylene oxide 100% alcohol

ethylene oxide

Rank the following events in order from GREATEST to LEAST contribution to the spread of antibiotic resistance in bacterial populations.

horizontal transfer vertical transfer new mutations

If you wanted to evaluate a new disinfectant for effectiveness under the conditions of its intended use, the best evaluation technique would be the __________ test. phenol coefficient use-dilution Kelsey-Sykes capacity in-use

in-use

A Salmonella virulence operon has three genes that are important for invasion of host cells. These proteins are not produced when the bacteria are growing outside of the host, and are only produced when the bacteria are growing inside the host. Based on this information, how many promoters are there, and what is the mode of regulation? 1; repressible 3; repressible 1; inducible 3; inducible

1; inducible

What is DOT? Done on Tuesday Department of Transportation Directly Observed Therapy Died of the Treatment

Directly Observed Therapy

Many MRSA strains are sensitive to other antibiotics. Which of the following methods would be the best way to evaluate sensitivity to other antibiotics? Disk diffusion Growth on high salts Gram stain Assay for a PBP2a allele

Disk diffusion

Penicillin's target is transpeptidase, a protein involved in cell wall synthesis. For a Gram-positive bacterium, which of the following mechanisms would be most effective in resisting penicillin's effects? Drug inactivation via β-lactamases and altered target binding site Drug inactivation via β-lactamases and use of efflux pumps to move the drug out of the cell Drug inactivation via β-lactamases Decreased permeability via alteration of porins and use of efflux pumps to move the drug out of the cell

Drug inactivation via β-lactamases and altered target binding site

Which of the following activities can be shown to increase resistance among microbial populations? taking antibacterial drugs for viral infections taking a combination of antimicrobial drugs taking an antimicrobial drug for the entire prescribed time developing second- and third-generation versions of antimicrobial drugs

taking antibacterial drugs for viral infections

What is microbial antagonism? microbes that cause food to smell bad and taste bad microbes that cause disease in humans the ability of the normal flora to outcompete and outgrow pathogens the overgrowth of opportunistic organisms when the normal flora are removed by antiseptic soaps

the ability of the normal flora to outcompete and outgrow pathogens

What is the therapeutic index? the dosage that kills 50% of the patients the range of drug dosage levels that are effective without being excessively toxic the drug dose the patient can tolerate divided by the effective dose the effective dose divided by the dose the patient can tolerate

the drug dose the patient can tolerate divided by the effective dose

When a patient is treated with antibiotics, __________. mutations occur in all of the bacterial cells sensitive bacterial cells multiply uncontrollably the drug will kill or inhibit the growth of all of the sensitive bacterial cells the drug will kill or inhibit the growth of all of the resistant bacterial cells mutations will occur in the sensitive bacterial cells, but not in the resistant bacterial cells

the drug will kill or inhibit the growth of all of the sensitive bacterial cells

Based on the animation, what is transferred during bacterial conjugation? RNA A conjugation pilus A bacterial plasmid A bacterial chromosome

A bacterial plasmid

Where are you likely to find an autoclave? in a chemistry lab in a high school cafeteria in the home in a dentist office

in a dentist office

One approach that is becoming more common in drug D&D is to search for antimicrobial-producing organisms in relatively pristine environments. A pristine environment is one that has been relatively unperturbed by humans and/or domestic animals. Your D&D team is searching for novel antimicrobials produced by bacteria in a remote area of a temperate rainforest in the Pacific Northwest. Which of the following terms would accurately describe your drug? Select all that apply. natural chemotherapeutic agent synthetic semisynthetic antibiotic

natural chemotherapeutic agent antibiotic

Why is polymyxin only used on the skin? It can disrupt the metabolic pathways found in humans. It is sensitive to degradation by acid, making oral delivery unsuitable. It can also damage living human cell membranes, but the drug is safely used on the skin, where the outer layers of cells are dead. It has no effect on bacteria that live in the GI tract..

It can also damage living human cell membranes, but the drug is safely used on the skin, where the outer layers of cells are dead.

What cellular macromolecule is the fertility factor comprised of? Carbohydrate Protein Nucleic acid Lipid

Nucleic acid

What role does pressure play in an autoclave? Pressure forces oxygen out of the autoclave. Pressure is applied to boiling water to prevent heat from escaping as steam. The pressure crushes microorganisms. Pressure speeds up the heating process.

Pressure is applied to boiling water to prevent heat from escaping as steam.

One aspect that must be evaluated during the development phase is the interaction of your drug with the host (i.e., what effect will the drug have on human cells?). There are several important factors to consider in this interaction, including the selective toxicity of your potential drug. Which of the following statements most accurately describes the principle of selective toxicity? Selective toxicity refers to the fact that antimicrobial agents target a particular microbial structure, molecule, or pathway to exert their effect. Selective toxicity refers to the ability of an antimicrobial to kill microbes with minimal damage to the host. Selective toxicity describes the fact that antimicrobials are more effective against certain microbes compared to others. Selective toxicity refers to the fact that the toxic effect of an antimicrobial varies depending upon the environmental conditions under which it is administered.

Selective toxicity refers to the ability of an antimicrobial to kill microbes with minimal damage to the host.

Which of the following mutations would not result in antibiotic resistance? Missense mutation Nonsense mutation Silent mutation Frameshift insertion Frameshift deletion

Silent mutation

How many codons code for the amino acid arginine? Four Six Three One

Six

A researcher mistakenly uses a heat-sensitive version of DNA polymerase in a PCR. Which of the following will occur? The PCR will not be able to stop. The PCR will proceed normally. The PCR will proceed normally, but an extremely large number of mistakes will occur. The PCR will stop after one cycle.

The PCR will stop after one cycle.

What most likely explains the recovery of live S strain cells from a mouse injected with heat-killed S strain mixed with live R strain cells? The S strain was revived by the presence of the host's immune system. The R strain cells picked up the capsules from the S strain cells. The R strain picked up the S strain DNA, enabling it to produce a capsule. The S strain fused with the R strain, making it resistant.

The R strain picked up the S strain DNA, enabling it to produce a capsule.

Which of the following amino acids is coded by only one codon? Tyr Glu His Trp Phe

Trp

What term is used to describe bacterial cells that can naturally take up DNA from their environment? competent cells Hfr cells electroporated cells auxotrophs

competent cells

Which of the following enzymes can make specific cuts in DNA molecules? restriction enzymes DNA ligase DNA polymerase reverse transcriptase

restriction enzymes

Which drug for the treatment of tuberculosis inhibits RNA production and colors body secretions red-orange? polymyxin penicillin rifampin erythromycin

rifampin

The cytosol of bacteria contain ____________ which has/have components different from those of the functionally equivalent structure of eukaryotes. 70S ribosomes 80S ribosomes a nucleoid a cytoskeleton a nucleus

70S ribosomes

Order the following steps from transcription through the initiation of translation.

1. Sigma factor recruits RNA polymerase to the gene promoter on the DNA strand 2. RNA Polymerase begins synthesizing RNA by creating a DNA bubble 3. Terminator DNA sequences loosen the grip of RNA polymerase and rho causes the release of the DNA strand 4. The smaller sunbunit of rRna attaches at the ribosomal binding site on the mRNA strand. 5. fMET-tRNA binds at the start condon 6. The larger subunit of rRNA is recruited

Arrange the following statements in chronological order.

1. The Ti plasmid is isolated and prepared for the insertion of foreign DNA 2. The gene for Bt toxin is isolated from the bacterium and inserted into the plasmid 3. The plasmid is taken up by a bacterium 4. The bacterium is used to introduce the Bt toxin gene into the chromosome of plant cells 5. A single plant cell is chosen to produce a plant that now produce Bt toxin

It has been determined that the temperature in an autoclave should reach __________ for sterilization. 212 degrees Fahrenheit 121 degrees Fahrenheit 100 degrees Celsius 121 degrees Celsius

121 degrees Celsius

Prokaryotes contain _____ ribosomes. 50S 30S 80S 70S

70S

Which of the following is a characteristic of an F+ cell? Ability to mate with an F- cell Presence of a fertility factor Ability to synthesize sex pili, presence of a fertility factor, and ability to mate with an F- cell. Ability to synthesize sex pili

Ability to synthesize sex pili, presence of a fertility factor, and ability to mate with an F- cell.

Assume that you have an antimicrobial agent specific for each of the targets listed below. Indicate which type of microbe would be most susceptible to the agent by placing it in the appropriate bin.

All bacteria: glycolytic enzymes, membrane proteins Gram-positive bacteria: peptidoglycan Gram-negative bacteria: none Viruses: envelope proteins All bacteria and viruses: nucleic acids

Which of the following attaches the target gene to a desired location? Plasmids Restriction enzymes DNA ligase Chromosomal DNA

DNA ligase

The molecule that seals the gaps between the pieces of DNA in the lagging strand is DNA polymerase. DNA ligase. RNA. the leading strand. the replication fork.

DNA ligase.

Which of the following build(s) new strands of DNA? The lagging strand Parental DNA The origins of replication The leading strand DNA polymerases

DNA polymerases

Why does Dr. Bell start Caleb on HIV therapy in addition to the antibiotics used to treat the tuberculosis? Dr. Bell prescribes Caleb extra medications to ensure a high enough dose to completely eliminate both pathogens. Dr. Bell prescribes Caleb HIV therapy because he does not think that Caleb will complete his regimen of antibiotics. Dr. Bell prescribes Caleb HIV therapy because the virus is not affected by the antibiotics used to treat tuberculosis. Dr. Bell prescribes Caleb HIV therapy because in conjunction with the antibiotics, it will eliminate the tuberculosis.

Dr. Bell prescribes Caleb HIV therapy because the virus is not affected by the antibiotics used to treat tuberculosis.

Each phrase below is applicable to a particular mechanism of antimicrobial resistance. Match each phrase to its respective mechanism. Each phrase below is applicable to a particular mechanism of antimicrobial resistance. Match each phrase to its respective mechanism.

Drug activation: Bacterial β-lactamases, antimicrobial altered Efflux pumps: Antimicrobial moved from inside to outside of cell, Active transport, Turning on transport mechanisms Decreased permeability: Bacterial porins, Tuming off transport mechanisms Altered binding site: Structural changes of drug target, Mutation of drug target

With this concern in mind, you make plans to increase the stringency of the SSOPs, and develop containment plans to minimize cross-contamination of the nozzles. As long as there is no trace of both bacterial species co-occurring in the same nozzles, you are confident that horizontal gene transfer will not occur. Before you can implement these changes, however, you need to review mechanisms of genetic transfer and gene expression. Consider the following statement: Bacteria can exchange genetic material through conjugation without the need for any protein structures or control mechanisms. Is this statement True or False?

False

Which of the following is an example of microbial control? Select all that apply. Sue washes off the vegetables before serving them in a meal. Mary warms food up in a microwave before putting it on the table. Sue uses bleach to clean the kitchen counters. Mary places leftovers in the refrigerator after the meal.

Sue washes off the vegetables before serving them in a meal. Sue uses bleach to clean the kitchen counters. Mary places leftovers in the refrigerator after the meal.

During DNA replication, which nucleotide will bind to an A nucleotide in the parental DNA? U T G A C

T

How does the ribosome know if the entering charged tRNA is correct? The incorrect tRNA does not fit into the A site. The anticodon on the tRNA base pairs to the codon on the mRNA. The preceding amino acid will not permit it to enter the A site.

The anticodon on the tRNA base pairs to the codon on the mRNA.

What is meant when a bacterium is said to become "resistant" to an antibiotic? The antibiotic kills or inhibits the bacterium. The antibiotic is metabolized by the bacterium, providing more energy for growth of the cell. The bacterium is neither killed nor inhibited by the antibiotic. The antibiotic mutates in a way that benefits the bacterium.

The bacterium is neither killed nor inhibited by the antibiotic.

What characteristic of the S strain allows it to evade the immune system of the mice? They are genetically engineered to be resistant to killing. They are naturally competent. The cells have a capsule. They are resistant to heat.

The cells have a capsule.

What must occur for bacterial conjugation to take place? The cells must come into contact with each other. Each cell must contain a plasmid. The cells must transfer RNA. One of the cells must be E. coli.

The cells must come into contact with each other.

If the patient were to get a subsequent urinary tract infection, what should the doctor prescribe knowing that she is susceptible to thrush? The doctor should prescribe the same antibiotic, since it worked, but should also include a medication for a yeast infection. The doctor should prescribe an antibiotic to treat yeast infections to protect against thrush. The doctor should prescribe an antibiotic specific for the bacterial species causing the urinary infection. The doctor should prescribe same antibiotic as before, since it did work, and watch for the development of thrush.

The doctor should prescribe an antibiotic specific for the bacterial species causing the urinary infection.

The preferred method of sterilization during drug production is heat. Heat sterilization can occur in two forms: moist or dry. Autoclaving is the most commonly used application of moist heat for sterilization. Which of the following statements about autoclaving is true? Choose the statement about autoclaving that is true. The effectiveness of an autoclave is dependent on an increase in pressure and corresponding increase in temperature. Autoclaving requires extensive exposure times in order to achieve sterilization. When autoclaving solid items, they should be wrapped in foil to help maintain sterility. Autoclaving is preferred over dry heat because it can effectively be used to sterilize a wide variety of items, including liquids, powders, metal instruments, and glassware.

The effectiveness of an autoclave is dependent on an increase in pressure and corresponding increase in temperature.

The project that you are working on was initiated in response to the growing threat of antibiotic resistance in both hospital and community settings. Even in the early discovery and development phase, it is important to think ahead to try to minimize the likelihood that bacteria will be able to evolve resistance to your new drug. Understanding how resistance emerges is an essential part of this process. Which of the following statements is NOT true regarding the evolution of antibiotic resistance in bacteria? The exposure of bacteria to an antibiotic causes the bacteria to produce resistance genes. Due to natural genetic variation within populations, resistant bacteria will be present--even in the absence of antibiotic. Bacteria can acquire plasmids conferring resistance through horizontal gene transfer. Resistance can emerge due to mutations in chromosomal genes.

The exposure of bacteria to an antibiotic causes the bacteria to produce resistance genes.

What is the initial target of RNA polymerase? The terminator region The template DNA The promoter

The promoter

How does specialized transduction differ from regular lysogeny? The prophage in specialized transduction carries with it pieces of the host chromosomal DNA. The resulting bacteriophage from specialized transduction cannot infect a new host cell. The prophage is not excised during specialized transduction. The resulting bacteriophage from specialized transduction does not contain any viral DNA.

The prophage in specialized transduction carries with it pieces of the host chromosomal DNA.

How can specialized transduction contribute to the transfer of antibiotic resistance genes in a bacterial population? The phage lyses the bacterium and releases resistance genes into the local environment, which can then be taken up by recipient cells. The phage causes the destruction of any antibiotic present during the specialized transduction process. The prophage takes an antibiotic resistance gene with it and is packaged with the newly synthesized viral DNA.

The prophage takes an antibiotic resistance gene with it and is packaged with the newly synthesized viral DNA.

In general, how might recombinant DNA technology be used to prevent a genetic disorder caused by a mutation in a single gene? To insert a desirable gene To insert a desirable gene, remove an undesirable gene, or replace a defective gene with a functioning gene To remove an undesirable gene To replace a defective gene with a working gene

To insert a desirable gene, remove an undesirable gene, or replace a defective gene with a functioning gene

Why are endospores sometimes used in sterility indicators? They are the hardest life form to kill. They release toxic gases that aid in the sterilization process. Endospores have the ability to kill all remaining microbes. Bacterial endospores release an indicator dye used to test for sterility.

They are the hardest life form to kill.

How do restriction enzymes cut DNA sequences? They have the ability to cut DNA randomly. They cut DNA at sequences that have lots of adenine bases. They cut DNA at sites, called recognition sites, that have specific nucleotide sequences.

They cut DNA at sites, called recognition sites, that have specific nucleotide sequences.

How do scientists ensure that autoclaved materials were actually sterilized? They inspect the materials under a microscope to search for contaminating microorganisms. They may place a sterility indicator with a special dye to detect the growth of endospores. There is no need to verify sterility when proper time, pressure, and temperature are maintained. They may take a sample of the media being sterilized and inoculate it onto a plate for incubation.

They may place a sterility indicator with a special dye to detect the growth of endospores.

Why is it difficult to find good chemotherapeutic agents against viruses? There is no effective way to deliver the drug to the virus. Viruses are not cells, and therefore not sensitive to such compounds. Viruses depend on the host cell's machinery, so it is hard to find a viral target that would leave the host cell unaffected. Viruses infect both bacteria and human cells.

Viruses depend on the host cell's machinery, so it is hard to find a viral target that would leave the host cell unaffected.

How is translation terminated? When there are no more charged tRNA molecules When the A, P, and E sites are all filled When a protein called a release factor enters and binds to the A site When the ribosome runs out of the mRNA

When a protein called a release factor enters and binds to the A site

Which of the following is NOT an important consideration when preparing to use a chemical to disinfect a diaper changing table in a public restroom? View Available Hint(s) Whether or not the changing table is visibly soiled The label directions for contact time Whether or not the chemical is compatible with the material that the changing table is made of Whether or not hand sanitizer is available at the changing table

Whether or not hand sanitizer is available at the changing table

While in the development phase, you are also required to determine both the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for your drug. While these values directly relate to the efficacy of the drug against bacteria, they will also be informative for the next stages of development, which include studies to determine effective dosages within a host. The picture depicts the results of an MBC test. Based on these data, the MIC for your drug would be __________ and the MBC would be __________. There is a scheme representing bacterial sensitivity to an antibacterial drug. There are 3 test-tubes. Each tube contains a bacterial culture. Bacteria from these test-tubes were cultivated on a drug-free media. From the bacterial culture obtained from the tube with the concentration of the drug of 8 micrograms per milliliter bacterial, colonies arose. From the cultures obtained from tubes with the concentration of the drug of 16 and 25 micrograms per milliliter no colonies grew. 8 μg/ml; 25 μg/ml 16 μg/ml; 25 μg/ml 16 μg/ml; 8 μg/ml 8 μg/ml; 16 μg/ml

8 μg/ml; 16 μg/ml

Which of the following choices correctly matches the class of antibiotic and its mode of action? Select all that apply. Aminoglycosides and tetracyclines are inhibitors of protein synthesis. Penicillins and cephalosporins inhibit nucleic acid synthesis. Sulfonamides inhibit the synthesis of essential metabolites. Lipopeptides inhibit cell wall synthesis.

Aminoglycosides and tetracyclines are inhibitors of protein synthesis. Sulfonamides inhibit the synthesis of essential metabolites.

When a nurse rubs your skin with rubbing alcohol prior to administering an injection, what process(es) is he carrying out? Select all that apply. Degerming Antisepsis Sanitization Disinfection

Degerming Antisepsis

Each of us typically use one or more of a handful of household disinfectants to limit microbial growth around our kitchens and bathrooms. They work in different manners, and their use is often specific to an area of the house. Match each of the methods of microbial control with an example of its use.

An oven is an example of dry heat. Drying out fruit to remove water is an example of desiccation. Ultraviolet rays that damage microbial DNA is an example of nonionizing radiation. Chlorinating pools is an example of halogens. Using isopropanol is an example of alcohols. Using soap is an example of surfactants. Silver creams are examples of heavy metals.

Why does the physician start Caleb on the antibiotic azithromycin before laboratory results come back? Antibiotic therapy is started before culture results are obtained because all of the pathogens that cause lower respiratory infections grow very slowly in the laboratory. Caleb would die if treatment were delayed until cultures grew. Antibiotic therapy is started with a broad-spectrum antibiotic because broad-spectrum antibiotics are effective against many gram-positive and many gram-negative bacteria. Antibiotic therapy is started with a narrow-spectrum antibiotic because narrow-spectrum antibiotics are effective against many gram-positive and many gram-negative bacteria. Antibiotic therapy is started with a broad-spectrum antibiotic because broad-spectrum antibiotics are effective against only gram-negative bacteria.

Antibiotic therapy is started with a broad-spectrum antibiotic because broad-spectrum antibiotics are effective against many gram-positive and many gram-negative bacteria.

Antimicrobial X targets a specific protein in the cytoplasm of the bacterial cell, causing the bacteria to stop growing, but does not kill them. A few bacteria start to grow in the presence of antibiotic X. Analysis of the bacteria that can now grow shows that they have changed the shape of the target for antimicrobial X. What conclusion can be made? Antimicrobial X is more effective against the new shape of its target. The change in shape of the target for antimicrobial X had no effect on the effectiveness of antimicrobial X. Antimicrobial X is less effective against the new shape of its target.

Antimicrobial X is less effective against the new shape of its target.

Organisms are either eukaryotes or prokaryotes. Prokaryotes are further classified into the domains Archaea or Bacteria, while all eukaryotes are in the domain Eukarya. All three domains have some cell structures in common, whereas other structures are found in members of only one or two domains. Match the following descriptions of cellular structures with the type of cell in which they are found.

Archaea: Hami, protein cell wall Bacteria: Peptidoglycan cell wall Eukaryotes: Organelles, 80S ribosome in cytosol Both Eukaryotes and Prokaryotes: Cytoskeleton, DNA, Glycocalyx Prokaryotes (Archaea and Bacteria): Fimbriae, 70S ribosome in cytosol

Why is autoclaving rather than boiling water used for sterilization? Boiling water does not kill everything, including bacterial endospores and some protozoan cysts. Autoclaving uses dry heat instead of water. Autoclaving is much faster than boiling water. Boiling water is too hot and may denature proteins.

Boiling water does not kill everything, including bacterial endospores and some protozoan cysts.

What causes thrush? Streptococcus mutans Candida albicans methicillin-resistant Staphylococcus aureus Penicillium notatum

Candida albicans

Dr. Paul Ehrlich observed that the differential stain developed by Dr. Gram suggested bacteria could be killed differentially by chemicals (Chapter 1). He called these potential antibacterial agents "magic bullets". Which among the following cell features of bacteria are potential targets for Dr. Ehrlich's "magic bullets" due to significant difference or absence from humans? Choose all that apply. Glycocalyx Cell wall DNA Cytoskeleton Cytoplasmic membrane Ribosome

Cell wall Ribosome

What is meant by selective toxicity? Chemotherapeutic agents should work on certain types of pathogens. Chemotherapeutic agents should work on many different targets on a pathogen. Chemotherapeutic agents should act against the pathogen and not the host. Chemotherapeutic agents should have only one mode of action.

Chemotherapeutic agents should act against the pathogen and not the host.

Quinolones and fluoroquinolones act against what bacterial target? Cell walls Bacterial ribosomes Metabolic pathways unique to bacteria Cell membranes DNA gyrase

DNA gyrase

According to Strachan's "hygiene hypothesis," certain human behaviors may lead to a decrease in exposure to microbes and, thus, an increase in childhood immune disorders. Place the items associated with decreased exposure to microbes in the bin marked "Decreased Exposure." Place all items associated with increased exposure to microbes the bin marked "Increased Exposure."

Decreased Exposure: discarding away food that falls on floor, wiping surfaces with disinfectants, remaining indoors, washing hands regularly Increase Exposure: being involved in team sports, sharing food or drink with family, having pets, gardening outside

A Gram-positive bacterial strain is simultaneously treated with two different antimicrobials: Drug A, which targets a protein involved in cell wall synthesis, and Drug B, which targets ribosomes involved in translation. The bacteria continue to grow during the course of treatment, indicating resistance to both antimicrobials. What are all the possible resistance mechanisms this bacterial strain could have? Check all that apply. Decreased permeability Drug inactivation Altered drug target Efflux pumps

Decreased permeability Drug inactivation Altered drug target Efflux pumps

Based on the data shown, what are the possible resistance mechanisms of this patient's resistant strain of K. pneumoniae? Decreased permeability Efflux pumps Drug inactivation Altered drug target

Decreased permeability Efflux pumps Drug inactivation Altered drug target

Which of the following statements is MOST correct regarding the development of antibiotic resistance in populations of bacteria? The bodies of people who take antibiotics become resistant to them. Bacteria exposed to antibiotics alter their DNA to become resistant. Exposure to antibiotics causes mutations which produce resistant bacteria. Exposure to antibiotics selects for the members of a bacterial population which already have a resistant phenotype.

Exposure to antibiotics selects for the members of a bacterial population which already have a resistant phenotype.

A common mechanism for antibiotic resistance is alteration of the molecule targeted by the antibiotic. Very small changes in the structure to extensive alterations may produce a gene product on which the antibiotic has limited effect. Match the type of point mutation with the type of damage it is most likely to produce.

Frameshift: Extensive change in gene product structure and function. Nonsense: Premature termination of gene product with probable loss of function. Silent: No change in gene product. Missense: Small change in gene product which may or may not alter function.

Clostridium difficile is a common healthcare associated infection. It is a Gram-positive spore-forming anaerobe that is associated with antibiotic therapy. It is most commonly transferred between patients on the hands of health care workers. Based on this information, rank the following prevention and control strategies from most beneficial (1) to least beneficial (4).

Hand hygiene with soap and water Use of gloves Use of approved chemical disinfectants in patient rooms Hand hygiene with alcohol gels

Why are chemotherapeutic agents that work on the peptidoglycan cell wall of bacteria a good choice of drug? Bacteria are especially sensitive to these compounds. The drugs also work against DNA gyrase. Humans and other animal hosts lack peptidoglycan cell walls. They are less expensive that other chemotherapeutic agents.

Humans and other animal hosts lack peptidoglycan cell walls.

Why do containers of liquid placed in an autoclave need to remain at least slightly open? If they remain closed, they may implode. A closed container would block any heat from entering the media. to allow oxygen to penetrate the media so that you may pour out the contents into sterile containers before the temperature drops below 100 degrees Celsius

If they remain closed, they may implode.

Which of the following contribute to drug resistance in M. tuberculosis? Select all that apply. Many individuals fail to complete their entire regimen of antibiotics. Some physicians prescribe the wrong medication, the wrong dosage, or the wrong length of time for treating tuberculosis. In many areas, tuberculosis antibiotics are unavailable or of poor quality. M. tuberculosis is an acid-fast bacterium; this characteristic allows it to become resistant to antibiotics faster than other bacteria.

Many individuals fail to complete their entire regimen of antibiotics. Some physicians prescribe the wrong medication, the wrong dosage, or the wrong length of time for treating tuberculosis. In many areas, tuberculosis antibiotics are unavailable or of poor quality.

Not all changes in amino acid sequence are deleterious, some may even be beneficial. Which of the following point mutations is most likely to alter a protein product without destroying its function? Silent Missense Frameshift Nonsense

Missense

In examining a MRSA strain, researchers find that degraded penicillin is found in the culture medium. What is the most likely mechanism of resistance? Alteration of a penicillin-binding protein (PBP) Production of a beta-lactamase Alteration of a porin Production of an efflux pump

Production of a beta-lactamase

Point mutations are those that alter a single base pair or base location, and include substitutions and frameshift mutations. They can range in severity from no phenotypic change to complete loss of function. Rank the following point mutations in order of least damaging to most damaging if they occur in the middle of the coding sequence of a polypeptide.

Silent Missense Frameshift Nonsense

What is a superinfection? A superinfection is one that is caused by a eukaryotic organism. Superinfection is a disease caused by an organism that is often an opportunist or one that was present in low numbers. Superinfection is a sequel to removal of the normal flora by antibiotic treatment. A superinfection is caused by a multidrug resistant organism. A superinfection is one that is caused by a viral organism.

Superinfection is a disease caused by an organism that is often an opportunist or one that was present in low numbers. Superinfection is a sequel to removal of the normal flora by antibiotic treatment.

Which category of drug is complementary to mRNA of the pathogen? oxazolidinones tetracyclines macrolides antisense nucleic acids

antisense nucleic acids

The use of lysozyme during the preparation of cheeses and wines is effective in reducing the numbers of bacteria. fungi. prions. all microbes. viruses.

bacteria.

R-plasmids are most likely acquired via Check all that apply. translation. bacterial conjugation. transformation. transduction.

bacterial conjugation

Formalin (37% formaldehyde) is used for antisepsis. sanitization. disinfection. sterilization. both disinfection and sterilization.

both disinfection and sterilization.

Strachan suggested the "hygiene hypothesis" in 1989, although his idea is almost impossible to demonstrate experimentally. Since Strachan's hypothesis is almost impossible to demonstrate using experimentation, how did he most likely arrive at such an assertion? through the observation that older people rarely get sick by comparing vaccination records of individuals with immune disorders and those without by intentionally exposing children to various pathogens by comparing cases of allergy-associated disorders from years past to those of the present

by comparing cases of allergy-associated disorders from years past to those of the present

Polymyxin is effective against only some Gram-negative bacteria; therefore, it is considered a __________. host-specific drug intermediate-spectrum drug narrow-spectrum drug broad-spectrum drug

narrow-spectrum drug

Which category of antimicrobial drug essentially acts to stall a ribosome as it reads mRNA? tetracyclines chloramphenicol antisense nucleic acids macrolides

macrolides

What does MDR mean? multi-directional radioactivity multi-drug-resistant minimal drug resistance map directed route

multi-drug-resistant

The first true antibiotic was __________, which was discovered by __________. penicillin; Alexander Fleming sulfanilamide; Gerhart Domagk streptomyces; Selman Waksman arsenic compounds; Paul Enrich

penicillin; Alexander Fleming

The ____________ is a defining characteristic of bacteria which is not found in eukaryotes and is therefore a good choice for chemotherapeutic agents. phospholipid cytoplasmic membrane steroid lipid cytoplasmic membrane peptidoglycan cell wall carbohydrate glycocalyx protein cell wall carbohydrate cell wall

peptidoglycan cell wall

Strachan's hypothesis not only includes fewer exposures to pathogens but also fewer exposures to everyday microbes that do not normally cause people to become ill. Exposure to which of the following microscopic substances will most likely lead to an allergy in an individual with an over reactive immune system? disinfectants viruses bacteria pollen

pollen

Chloramphenicol blocks the action of the large (50S) subunit. This essentially _____. prevents the formation of peptide bonds changes the shape of the large subunit prevents a large subunit from attaching to a small subunit prevents the attachment of tRNA to a ribosome

prevents the formation of peptide bonds

If Caleb's strain of M. tuberculosis is sensitive to antibiotic treatment, which of the following could be used to treat his infection? Select all that apply. streptomycin penicillins and cephalosporins isoniazid and ethambutol rifampin

streptomycin isoniazid and ethambutol rifampin

Strachan suggests that fewer exposures to childhood illnesses may lead to unintended consequences, including an increase in overreactions of the immune system (allergies). According to the readings in Chapter 9, which of the following is a chemical method to control the growth of microbes? radiation desiccation moist heat surfactants

surfactants

Antimicrobial drugs are selectively toxic. This means _____. the drugs will not have toxic effects on a patient the drugs will affect only a particular type of pathogen the drugs are reactive within a specific part of the patient's anatomy (for example, the inner ear) the drugs are more toxic to the pathogens than to the patient

the drugs are more toxic to the pathogens than to the patient

Handwashing with regular soap is effective because __________. the hydrophobic end of the soap molecule attaches to the cell wall of bacteria and the hydrophilic end of the molecule attracts water. The result is that the bacteria are washed away with the water soap is an excellent antimicrobial agent the hydrophobic end of the soap molecule breaks up oily deposits and the hydrophilic end of the molecule attracts water. This combination makes soap a good de-germing agent the fatty acid tail of a soap molecule is an excellent oxidizing agent, while the opposite end of the molecule contains alcohol

the hydrophobic end of the soap molecule breaks up oily deposits and the hydrophilic end of the molecule attracts water. This combination makes soap a good de-germing agent

What is the purpose of an autoclave? to incubate cultures to wash equipment to sterilize equipment and media to warm up cultures

to sterilize equipment and media

The process of acquiring antibiotic resistance by means of bacteriophage activity is called transduction. R-plasmid acquisition. point mutation. transformation.

transduction.

Which of the following will most likely contribute to the spread of a genetic mutation among bacterial species? transduction transformation vertical transmission sexual reproduction transposition

transformation

Who was the most likely source of infection for this child? uncle grandmother sister mother

uncle

Which of the following procedures is currently the standard test used in the United States for evaluating the efficiency of antiseptics and disinfectants? phenol coefficient use-dilution test Kelsey-Sykes capacity test in-use test microbial death rate

use-dilution test

Which of the following classifications would best describe Candida albicans? protozoan yeast RNA virus bacteria

yeast

Some believe that if you drop a piece of food on the ground, you have approximately five seconds to pick it up and eat it. If you leave it longer than five seconds and eat it, you will likely become sick. In light of the "hygiene hypothesis," there may be some truth to the "Five-Second Rule." If one were to ascribe to the Five-Second Rule, which of the following places would be the most appropriate place to apply it? a library a school your home a hospital

your home

GAU codes for serine. proline. tryptophan. isoleucine. aspartic acid.

aspartic acid.

At which point does a recipient cell become an F+ cell? 1. Fusion of the cell membranes 2. Attachment of the sex pilus 3. Transfer of the single stranded F factor 4. Pulling of donor and recipient cells together 5. Formation of the complementary strand of the F factor 2 4 5 1 3

5

During elongation, how is the RNA synthesized? 3' to 5' Left to right 5' to 3' Right to left

5' to 3'

What kind of bond is formed when two amino acids join together? A peptide bond An ionic bond A polar bond A hydrogen bond

A peptide bond

Which of the following best explains why the pressure cooker is so important in the canning process? A pressure cooker utilizes normal atmospheric pressure for longer-than-normal cooking times in order to prevent the growth of microbial contaminants and possible endospores. A pressure cooker utilizes steam to create a higher-pressure environment that allows the food to cook at higher temperatures than normal. The higher temperatures kill most contaminating microbes and endospores and therefore effectively sterilize the food. Pressure cookers utilize temperatures that kill only the pathogenic organisms and leave behind the nonpathogenic ones to enhance the flavor of the food. Pressure cookers utilize pressure and dry heat to create an environment that will remove harmful organisms from the food contents. Dry heat is the most effective method of eliminating endospores.

A pressure cooker utilizes steam to create a higher-pressure environment that allows the food to cook at higher temperatures than normal. The higher temperatures kill most contaminating microbes and endospores and therefore effectively sterilize the food.

What would happen if the mRNA codon that coded for Cys was mutated in the third position from a U to an A? The codon would now code for Trp instead of Cys. A stop codon would be introduced prematurely. The amino acid Cys would still be coded.

A stop codon would be introduced prematurely.

A strain of E. coli has been isolated from a patient with serious diarrhea. In addition to its chromosome, it has a plasmid. Strains that lose the plasmid become non-pathogenic, and non-pathogenic strains are able to cause diarrhea if transformed with the plasmid. What type of plasmid is this? An (F) plasmid An (R) plasmid A virulence plasmid A bacteriocin plasmid

A virulence plasmid

How does an F+ cell differ from an Hfr cell? Hfr strains can no longer reproduce. F+ cells have no plasmids. Hfr strains have the F plasmid integrated into the chromosome. Hfr cells cannot perform conjugation.

Hfr strains have the F plasmid integrated into the chromosome.

What is the key difference between donor cells and recipient cells? Cell membranes An F plasmid A chromosome Size

An F plasmid

Why is DNA replication essential for a cell? An organism must copy its DNA to pass genetic information to its offspring. Because DNA is double-stranded. It allows the organism to repair any mistakes. All organisms require two copies of DNA.

An organism must copy its DNA to pass genetic information to its offspring.

Part complete If the inserted sequence had been complete except for missing the last 54 nucleotides (and thus the stop signal), would a working protein be possible? No; an altered DNA sequence would lead to an altered amino acid sequence that would misfold. Lacking the termination codon, the ribosome would continue translating codons in the wrong reading frame until a stop codon is reached. This could lead to an increase in size for the protein, and the additional motifs may interfere with proper folding. Both yes and no are probable. DNA sequencing after the inserted gene would need to be done to see whether any stop signals would be in the correct reading frame or what possible amino acids would be added to the protein. Yes, but the carboxy-terminus of the protein would be lengthened until a stop codon was reached by the ribosome. With the beginning 401 amino acids there, the possibility of the protein motifs required for correct protein folding would be high.

Both yes and no are probable. DNA sequencing after the inserted gene would need to be done to see whether any stop signals would be in the correct reading frame or what possible amino acids would be added to the protein.

PFGE is a form of DNA fingerprinting used to compare bacterial isolates. Restriction enzymes are used to generate large DNA fragments that can be separate by gel electrophoresis and compared. On the gel below, which sample has been cut by the most appropriate restriction enzyme for PFGE fingerprinting? Gel electrophoresis. Lane A: Solid purple block in the well. Lane B: Small solid purple block below well. Lane C: purple lines below well decreasing in frequency away from the well. Lane D: purple lines of nearly equal frequency near the bottom of the gel. A B C D

C

Bacterial conjugation is often referred to as bacterial sex. Why is this term inaccurate? Sex is a phenomenon only seen in animals. It does not require two cells to occur. Bacteria are neither male nor female. Conjugation does not result in the formation of new offspring.

Conjugation does not result in the formation of new offspring.

Which statement about conjugation is false? E. coli is the model for bacterial conjugation. Conjugation is a process of bacterial reproduction. After conjugation, each cell involved has a copy of the shared DNA.

Conjugation is a process of bacterial reproduction.

Why does conjugation between an Hfr strain and an F- strain not result in two Hfr strains? The cell membranes between the two strands never fuse together. The transferred genes typically recombine with the recipient chromosome. Hfr strains lack fertility factor. Conjugation is typically disrupted before the fertility factor can be transferred.

Conjugation is typically disrupted before the fertility factor can be transferred.

During production of a drug, all work area surfaces must be disinfected using sterilized disinfectants. Which of the following statements about disinfectants are true? Select all that apply. Disinfectants destroy all microbes present on a surface. Disinfection can be used to treat work surfaces as well as workers (i.e., washing hands). Endospores and viruses can resist disinfectant treatment. Disinfection can occur by physical or chemical means. Disinfectants are used to inhibit or destroy pathogens.

Endospores and viruses can resist disinfectant treatment. Disinfection can occur by physical or chemical means. Disinfectants are used to inhibit or destroy pathogens.

Which statement about DNA replication is FALSE? Because the two strands of parental DNA run in opposite directions, the new strands must be made in different ways. The two strands of parental DNA are separated during DNA replication. DNA ligase adds nucleotides to the lagging strand. DNA polymerase builds a new strand by adding DNA nucleotides one at a time. The lagging strand is made of a series of pieces that must be joined together to make a continuous strand.

DNA ligase adds nucleotides to the lagging strand.

Synthetic nucleic acids are useful as DNA probes. primers for PCR. antisense RNAs. DNA probes and antisense RNAs. DNA probes, primers, and antisense RNAs.

DNA probes, primers, and antisense RNAs.

What is required by an F- cell to become an F+ cell? F+ chromosome Conjugation pilus F plasmid An F- cell to be a recipient

F plasmid

Use of moist heat can control microbial growth in many circumstances, but heat-sensitive items and those susceptible to moisture cannot be sterilized in this manner. Which of the following correctly describes a method of physical control used to control microbial growth on or in such items? Select all that apply. Filtration is the passage of a liquid or a gas through a screenlike material with pores small enough to retain microorganisms. A vacuum is typically used to force the liquid through the mesh, and then the sterile liquid or gas is collected in a sterile container on the other side. Nonionizing radiation, such as UV light, has a wavelength longer than that of ionizing radiation. The wavelengths of UV light are absorbed by cellular DNA in organisms directly exposed to the light. Desiccation is a process that removes water from microorganisms, leaving them unable to grow or reproduce, but still viable. Osmotic pressure is a process that uses high concentrations of salts and sugars to preserve food.

Filtration is the passage of a liquid or a gas through a screenlike material with pores small enough to retain microorganisms. A vacuum is typically used to force the liquid through the mesh, and then the sterile liquid or gas is collected in a sterile container on the other side. Nonionizing radiation, such as UV light, has a wavelength longer than that of ionizing radiation. The wavelengths of UV light are absorbed by cellular DNA in organisms directly exposed to the light. Desiccation is a process that removes water from microorganisms, leaving them unable to grow or reproduce, but still viable. Osmotic pressure is a process that uses high concentrations of salts and sugars to preserve food.

How is generalized transduction different from specialized transduction? Generalized transduction is initiated during lytic cycle of a virulent bacteriophage; specialized transduction is initiated during the lysogenic cycle of a temperate bacteriophage. Only one specific host gene is transferred in both specialized transduction and generalized transduction. Specialized transduction uses animal viruses instead of bacteriophage. Generalized transduction is initiated by a lysogenic bacteriophage; specialized transduction is initiated by a lytic phage.

Generalized transduction is initiated during lytic cycle of a virulent bacteriophage; specialized transduction is initiated during the lysogenic cycle of a temperate bacteriophage.

__________ can be used to advise prospective parents about their risk of transmitting genetic disorders, such as Huntington's Disease, to their offspring. Gene therapy Polymerase chain reaction Vaccine production Genetic screening

Genetic screening

Bt crops, including potatoes and cotton, are genetically engineered using laboratory techniques. Which of the following utilizes recombinant DNA technology to produce advantageous traits in the crops that are produced? Genetically engineered crops have natural characteristics that give them a genetic advantage. Genetically engineered crops have a genetic advantage because the parent strains have advantageous traits. Genetically engineered crops have an advantageous gene from another organism inserted into their genome. Genetically engineered crops naturally produce larger plants and bountiful products.

Genetically engineered crops have an advantageous gene from another organism inserted into their genome.

The department's microbiology lab has performed strain characterization assays of the biofilm-grown L. monocytogenes isolated from Company Q. These results show new proteins during proteome analysis and new DNA bands from chromosomal digestion. This leads you to conclude that this new strain of L. monocytogenes has been transformed by the addition of new genes for biofilm formation and chemical resistance. Each description below illustrates one way that genetic material is shared between cells. Categorize each item as a HORIZONTAL or VERTICAL gene transfer event.

Horizontal Gene Transfer- gaining a single new gene sequence from outside the cell, infection by a prophage containing a partial bacterial operon, uptake and insertion of a transposable element carrying foreign genes Vertical Gene Transfer- mitosis to fom two daughter cells, two haploid cells fusing to form a diploid cell, binary fission of a bacterial cell

How can hospital personnel prevent the spread of resistant Enterococcus faecium throughout the hospital? Hospital staff should wear masks when entering a patient's room. Hospital staff should never serve raw fruit and salads to patients. Hospital staff should wear shoe covers for the duration of their shift. Hospital personnel should wash their hands when entering and leaving a patient's room.

Hospital personnel should wash their hands when entering and leaving a patient's room.

Where would one find an uncharged tRNA molecule in a ribosome? In the A, P, and E sites In the A site In the A and P sites In the P site In the E site In the P and E sites

In the P and E sites

How would one increase the concentration of a particular polypeptide in a cell? Increase the level of transcription Increase the concentration of promoters Increase the amount of DNA

Increase the level of transcription

Bt crops are engineered in the lab to produce Bt toxins due to the presence of a bacterial gene from B. thuringiensis. Why is it advantageous for the plants to produce the Bt toxin? The Bt toxin will protect the plant from pathogenic bacteria. The plant will release chemicals that will repel all nearby insects. People who eat the food produced by a Bt crop will be resistant to bacterial infections. Insects that normally destroy non-toxin-producing crops will be killed when they eat plants that do produce the toxin.

Insects that normally destroy non-toxin-producing crops will be killed when they eat plants that do produce the toxin.

What benefit does the F- strain receive from mating with an Hfr strain? It picks up a fertility factor. It acquires new, potentially beneficial genes from the Hfr strain. It can now produce sex pili. It becomes an F+ cell.

It acquires new, potentially beneficial genes from the Hfr strain.

Why would a recombinant DNA molecule be inserted into a host cell? It can protect the recombinant DNA. It can be copied, transcribed, and translated into a desired protein. Plasmids cannot be isolated outside of a host cell. Restriction enzymes can only be used inside of a cell.

It can be copied, transcribed, and translated into a desired protein.

What is a nosocomial infection? It is a nutritional deficiency aggravated by hospital food that is served cold. It is a hospital-acquired infection. It is a MRSA infection. It is an infection acquired by swimming in contaminated lake water.

It is a hospital-acquired infection.

What is the function of the conjugation pilus? It pulls the F+ and F- cells together. It contains an F plasmid. It converts F- cells into F+ cells. It carries the chromosome of F- cells.

It pulls the F+ and F- cells together.

What is the function of the parental DNA in replication? It is passed into the offspring of the parent. It gives the cell two complete copies of the DNA. It allows for the DNA to be circular. It serves as the template for DNA replication.

It serves as the template for DNA replication.

As shown in the animation, the start codon also codes for which amino acid? Methionine Proline Glycine Alanine Serine

Methionine

An R (resistance) plasmid can be transferred from E. coli to Salmonella in culture. Which of the following would suggest that transformation is the transfer mechanism? Plasmid is only found in recipient when there is direct between donor and recipient. Plasmid is only found in the recipient only when F (fertility) plasmid sequences are present. Plasmid is not found in the recipient when DNase is added to the culture medium. Plasmid is found in recipient cells only when phages are present.

Plasmid is not found in the recipient when DNase is added to the culture medium.

At each stage of production, sterility of the preparation is a major consideration. When considering appropriate measures to implement to control microbial growth, one must think about the susceptibility of possible microbial contaminants. Apply your knowledge of the structural features of microbes and the mechanisms of action for antimicrobial agents to rank the following microbes according to their susceptibility.

Prions, endospores, Gram-negative bacteria, Gram-positive bacteria, and enevlope virus

Which finding is most surprising from Griffith's experiments? S strains are able to escape phagocytosis. S strain cells are isolated from the blood of mice infected with heat-killed S strains and live R strains. R strain cells fail to produce a capsule. S strain cells kill the mice.

S strain cells are isolated from the blood of mice infected with heat-killed S strains and live R strains.

Which of the following statements regarding vectors is FALSE? A useful vector contains multiple restriction sites for insertion of DNA. Cloning vectors include a "marker" to facilitate identification of cells containing them. Vectors are generally over 100,000 base pairs in size. Cloning vectors frequently contain sequences necessary for expression of inserted sequences. Vectors are usually autonomously replicating DNA molecules.

Vectors are generally over 100,000 base pairs in size.

Which of the following is an application that uses PCR? Sequencing a gene Sequencing a gene, diagnosing a disease, and providing enough DNA for cloning into another organism Diagnosing a disease Providing enough DNA for cloning into another organism

Sequencing a gene, diagnosing a disease, and providing enough DNA for cloning into another organism

Botulism food poisoning is a preventable illness if special precautions are taken during food preparation. In this case, what could Sue have done to prevent the outbreak of botulism? Select all that apply. Sue noticed that the pressure cooker was malfunctioning during the canning process. She should have fixed the instrument, borrowed a properly working one, or purchased a new pressure cooker. Sue could have lightly heated the food before serving it to her family members. Sue could have boiled the food for at least 10 minutes before serving it to her family members. She could have discarded all of the home-canned food and started over with the same pressure cooker.

Sue noticed that the pressure cooker was malfunctioning during the canning process. She should have fixed the instrument, borrowed a properly working one, or purchased a new pressure cooker. Sue could have boiled the food for at least 10 minutes before serving it to her family members.

Sodium nitrate and sodium nitrite are added to many meat products, such as ham, bacon, hot dogs, and sausage. These additives help to prevent the growth of Clostridium botulinum by inhibiting certain iron-containing enzymes of the organism. This is an example of chemical food preservation. Which of the following correctly describes a method of chemical control used to control microbial growth? Select all that apply. Surface-active agents, or surfactants, decrease surface tension among molecules of a liquid. Phenolics exert antimicrobial activity by injuring lipid-containing plasma membranes, which causes the cellular components to leak out of the cell. Alcohols exert their action by denaturing proteins and dissolving lipids. High pressure is used to denature proteins in vegetative cells.

Surface-active agents, or surfactants, decrease surface tension among molecules of a liquid. Phenolics exert antimicrobial activity by injuring lipid-containing plasma membranes, which causes the cellular components to leak out of the cell. Alcohols exert their action by denaturing proteins and dissolving lipids.

GM crops have raised issues among communities in which they are produced. Which of the following are concerns raised by the public about genetically engineered crops? Select all that apply. Genetically engineered crops could harm the economy. The Bt gene could ultimately make the plants pathogenic to humans. The Bt toxin could result in the death of non-pest species of insects. The Bt toxin could negatively affect the taste of the food that is produced from these crops.

The Bt gene could ultimately make the plants pathogenic to humans. The Bt toxin could result in the death of non-pest species of insects. The Bt toxin could negatively affect the taste of the food that is produced from these crops.

Which of the following best explains how scientists are able to introduce the bacterial gene for Bt toxin into the cotton plant genome? The bacterial gene for Bt toxin is isolated, and the DNA is put into tiny bullets (like BB's) that are "shot" into the cotton plant using a gene gun. The Bt toxin gene is isolated and inserted into a Ti plasmid from Agrobacterium tumefaciens. The engineered Ti plasmid is taken up by a bacterium that infects the cotton plant. A virus is engineered to contain the Bt toxin gene. This virus is then used to infect the plant and pass on the gene. The Bt toxin gene is added to water that is sprayed on the cotton plants. The gene is taken up through the roots of the plant.

The Bt toxin gene is isolated and inserted into a Ti plasmid from Agrobacterium tumefaciens. The engineered Ti plasmid is taken up by a bacterium that infects the cotton plant.

What was the MOST likely source of the family's botulism food poisoning? The family consumed botulism toxin in the chicken. The family consumed botulism toxin in the canned tomatoes. The family consumed botulism toxin in the canned green beans. The family consumed botulism toxin in the spinach salad.

The family consumed botulism toxin in the canned green beans.

How does genotype determine phenotype? Through the use of repressor genes, an individual can consciously create the physical features (phenotype) desired. The genotype includes all of the DNA of an individual and, therefore, provides information to make all phenotype structures. The genotype gives instructions for the structural, enzymatic, and regulatory proteins which result in the phenotype. The genotype directly gives instructions to make the proteins, carbohydrates, and lipids used to build the organism.

The genotype gives instructions for the structural, enzymatic, and regulatory proteins which result in the phenotype

What happens to the packaged DNA of a specialized transduced phage when it infects a new recipient cell? The host DNA integrates, with the prophage, into the new recipient chromosome. The DNA begins to replicate without integrating into the host chromosome. The DNA is chewed up by enzymes found in the recipient cell.

The host DNA integrates, with the prophage, into the new recipient chromosome.

Which statement about DNA replication is CORRECT? The leading strand is built continuously, and the lagging strand is built in pieces. The lagging strand is built continuously. The lagging strand is one of the strands of parental DNA. DNA ligase helps assemble the leading strand. The leading strand is one of the strands of parental DNA.

The leading strand is built continuously, and the lagging strand is built in pieces.

What is the end goal of PCR? To quickly increase the number of copies of a specific DNA sequence To increase the pool of different DNA sequences To allow cells to make DNA faster, thereby growing faster

To quickly increase the number of copies of a specific DNA sequence

What is unique about transduction compared to normal bacteriophage infection? Transduction transfers DNA from the chromosome of one cell to another. The bacteriophage does not erupt from an infected cell during transduction. The bacteriophage takes fragments of the cell with it during transduction.

Transduction transfers DNA from the chromosome of one cell to another.

Which of the following is an example of horizontal gene transfer in bacteria? Transduction Conjugation and transformation Conjugation Transformation Transduction, conjugation, and transformation

Transduction, conjugation, and transformation

What is the hallmark of all horizontal gene transfers? Transfer of DNA from parent to offspring Transfer of DNA using a virus The use of plasmids Transfer of DNA between organisms of the same generation

Transfer of DNA between organisms of the same generation

One alternative to autoclaving for sterilization of liquids is filtration. Imagine that you are using a filter to sterilize a drug solution. You use a filter with a 0.22 μm pore size. Which of the following microbes will effectively be removed by this filter? Select all that apply. bacteria such as E. coli yeast fungi small viruses

bacteria such as E. coli yeast fungi

Put the following events in the construction of a recombinant DNA molecule in the correct order: a. ligation of desired gene to plasmid DNA b. introduction of the plasmid into bacteria c. restriction enzymes cut gene of interest and plasmid DNA d. growth of cells on an antibiotic-containing medium a, d, c, b b, c, a, d c, a, b, d d, a, b, c

c, a, b, d

Competent cells are cells that can take up DNA from their surrounding environment and integrate it into their own chromosomes by recombination. have the ability to produce capsules. are killed by heat. are also considered "rough-strain" based on colony phenotype.

can take up DNA from their surrounding environment and integrate it into their own chromosomes by recombination.

If a scientist discovers a new gene, a functional genomic study using __________ may be used to determine what the gene does. gene knockout Southern blots PCR electrophoresis

gene knockout

A recombinant cell is a cell that receives DNA from an outside source and incorporates it into its own. is the result of a cell dividing. donates DNA into a new cell.

is a cell that receives DNA from an outside source and incorporates it into its own.

Which of the following is NOT a goal of recombinant DNA technology? creating organisms capable of producing useful products eliminating undesirable traits from livestock or crops combining genetic material from more than one organism to produce new useful organisms being able to remove or correct damaging traits in humans making it possible to clone humans

making it possible to clone humans

DNA sequencing of an E. coli colony isolated from a nozzle that had biofilm growth of both bacteria shows that conjugation has occurred. However, the transformed strain of E. coli did not express any new proteins. BLAST analysis shows that the gene for the L. monocytogenes protein is incomplete in E. coli. Sequence comparison shows that E. coli has a truncated version of the gene that begins at nucleotide number 54 and continues to nucleotide 1257, meaning that no start codon is present. Why would this interfere with transcription or translation? Select all that apply. DNA bases are species specific no start codon for translation no promoter region for the transcription to begin at E. coli DNA polymerase does not recognize an L. monocytogenes gene sequence

no start codon for translation no promoter region for the transcription to begin at E. coli DNA polymerase does not recognize an L.

PCR stands for polymerase copy reaction. polymerase chain reaction. polymerization copying rapidly.

polymerase chain reaction.

Mutagens are useful in biotechnology research for producing DNA fragments for cloning. selecting genetic mutants resistant to radioactivity. removing undesirable traits from microbes. producing organisms with altered phenotypes. producing new organisms which have beneficial traits from two or more organisms.

producing organisms with altered phenotypes.

Mice that are injected with only the R strain of Streptococcus pneumoniae become sick for prolonged periods of time. are killed, because R strain cells are deadly. stay healthy, because their immune systems can kill this strain easily.

stay healthy, because their immune systems can kill this strain easily.

RNA that has hydrogen bonded to itself forms a stem loop. terminator sequence. promoter sequence. termination protein.

stem loop.

RNA polymerase is guided by the coding strand of DNA. template strand of DNA. RNA strand.

template strand of DNA.

When a transducing phage interacts with a new host cell, it will cause the new cell to produce more transducing phage. the new host cell will be lysed. the DNA from the previous host can recombine with the new host chromosome.

the DNA from the previous host can recombine with the new host chromosome.