Chapter 10 Homework

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

70s ribosomes

If the MBC for a particular drug is 16 μg/ml, which of the following serial dilutions of the drug is likely to be the MIC? 1.6 μg/ml 8 μg/ml 24 μg/ml 32 μg/ml

8 μg/ml

Which of the following tests does NOT provide information on the lowest concentration of drug effective on a pathogen? E test both the E test and diffusion susceptibility test broth dilution test MBC test diffusion susceptibility test

E test? diffusion susceptibility test?

Membrane transport proteins are required for which mode(s) of antibiotic resistance? Modification of a metabolic enzyme Modification of a porins Efflux pumps, beta-lactamases, and modification of porins all utilize membrane transport proteins. Beta-lactamases Efflux pumps

Efflux pumps, beta-lactamases, and modification of porins all utilize membrane transport proteins.

How might efflux pumps increase antibiotic resistance in bacteria? Resistant bacteria may have a greater number of efflux pumps on their cell surfaces. Some bacteria can decrease the specificity of their efflux pumps, increasing the number of different antibiotics the pumps can eliminate. Some bacteria can change the chemical structure of the antibiotic. Efflux pumps can never be modified to increase antibiotic resistance. Resistant bacteria can have more efflux pumps, and can have less specific efflux pumps.

Resistant bacteria can have more efflux pumps, and can have less specific efflux pumps.

Which of the following statements is true of selective toxicity? Selective toxicity takes advantage of structural and/or metabolic differences between host and pathogen. Selective toxicity takes advantage of structural similarities between host and pathogen. Selective toxicity takes advantage of differences in metabolic rates of the host and pathogen. To be effective, an antimicrobial agent must be more toxic to the patient than the pathogen. Selective toxicity damages only pathogenic bacteria and not beneficial bacteria.

Selective toxicity takes advantage of structural and/or metabolic differences between host and pathogen.

Why is it difficult to find good chemotherapeutic agents against viruses? 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 are not cells, and therefore not sensitive to such compounds. There is no effective way to deliver the drug to the virus. 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.

Some bacteria are resistant to erythromycin as a result of mutation of their ribosomal RNA. What type of resistance does this represent? change in the permeability of the drug overproduction of an enzyme in a key metabolic pathway removal of the drug via a pump inactivation of the drug alteration of the target of the drug

alteration of the target drug

Nucleotide or nucleoside (acids/analogs/antisense) are antimicrobial agents that mimic the chemical structure of DNA building blocks.

analogs

Competition between beneficial microbes and potential pathogens is called microbial (antagonism/synergy/toxicity).

antagonism

Bacillus licheniformis secretes a compound that inhibits the growth of other Gram-positive bacteria. This is an example of a(n) porin. antibiotic. toxin. chemotherapeutic. analog.

antibiootic

Antimicrobials that block protein synthesis by binding to the mRNA are macrolides. aminoglycosides. antisense nucleic acids. beta-lactams. nucleic acid analogs.

antisense nucleic acids.

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. Antisepsis Sanitization Disinfection Degerming

antisepsis and degerming

Medications which block viral entry into cells include (adhesin/analog/attachment) antagonists.

attachment

Put the following routes of administration in order, from the route that results in the highest concentration of drug in the bloodstream to the route that results in the lowest concentration: a. topical b. intravenous c. oral d. intramuscular b, c, d, a a, c, d, b d, b, a, c b, d, c, a

b, d, c, a

Beta-lactam antibiotics such as penicillins, have an effect on which of the following types of cells? bacterial cells virus-infected cells animal cells fungal cells both animal and fungal cells

bacterial cells

An antimicrobial that inhibits bacterial cell wall synthesis will result in which of the following? No change in bacterial cell activity. Cytoplasmic membrane proteins lose their function. The sterols in the bacterial cell wall become nonfunctional. Bacteria cannot attach to their hosts. Bacterial cells become more susceptible to osmotic pressure.

bacterial cells become more susceptible to osmotic pressure

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

bacterial conjugation

A (bacteriocidial/bacteriostatic/minimum) concentration of a drug is one at which microbes survive but are not able to grow and reproduce.

bacteriostatic

Why is the drug actinomycin used only in research applications or in the treatment of cancer? because it is not a very effective drug because it causes severe allergic reactions in most patients because it is active against both prokaryotic and eukaryotic cells because it cannot be given orally, making it difficult to administer to patients

because it is active against both prokaryotic and eukaryotic cells

Bacteria that are resistant to sulfonamide have enzymes that have a greater affinity for what? PABA Sulfonamide Tetrahyrdrofolic acid Tetracycline

PABA

Who proposed the concept of chemotherapy, that compounds might selectively kill pathogens without harming people? Selman Waksman Alexander Fleming Gerhard Domagk Paul Ehrlich Joseph Lister

Paul Ehrlich

Disruption of the normal microbiota can result in infections caused by which of the following microbes? Streptococcus both Candida albicans and Clostridium difficile Mycobacterium Clostridium difficile Candida albicans

both Candida albicans and Clostridium difficile

Which of the following antifungals works by binding to ergosterol in membranes? amphotericin B fluconazole nystatin turbinafine both amphotericin B and nystatin

both amphotericin B and nystatin

Which of the following interferes with cell wall synthesis by blocking alanine bridge formation? vancomycin bacitracin cycloserine beta-lactams both cycloserine and vancomycin

both cycloserine and vancomycin

Which of the following can result when antibiotic therapy disrupts the normal microbiota? thrush anaphylactic shock black hairy tongue pseudomembranous colitis both pseudomembranous colitis and thrush

both pseudomembranous colitis and thrush

The broth dilution test can provide information for determining the rate of diffusion of an antibiotic. the MBC (minimum bactericidal concentration), with an additional step. the MIC (minimum inhibitor concentration). the molecular target of an antibiotic. both the MIC and the MBC (with an additional step).

both the MIC and the MBC (with additional step)

Infection of the ________ would be the hardest to treat with antimicrobial drugs. kidneys colon heart liver brain

brain

The drug metronidazole is effective on both bacteria and some protozoa. It can therefore be described as a ________ drug. broad spectrum general spectrum specific spectrum full spectrum narrow spectrum

broad spectrum

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

candida albicans

Bacitracin blocks the transport of NAG and NAM across the cytoplasmic membrane to the cell wall. Like other antimicrobials that block cell wall synthesis, this would result in weak cell walls and __________. inhibition of nucleic acid synthesis the inability to synthesize flagella cell lysis due to the effect of osmotic pressure less protein synthesis

cell lysis due to the effect of osmotic pressure

Drugs known as beta-lactams interfere with bacterial (DNA/folic acid/cell wall) synthesis.

cell wall

Any drug that acts against a disease is called a(n) (analog/antibiotic/chemotherapeutic) agent.

chemotherapeutic

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

The ratio of a medication's dose that can be tolerated to its effective dose is the therapeutic (MIC/index/range) of the medication.

index

Most broad-spectrum antibiotics act by inhibiting metabolic pathways. inhibiting the synthesis of the cell wall. disrupting the cytoplasmic membrane. inhibiting nucleic acid synthesis. inhibiting protein synthesis.

inhibiting protein synthesis

The mechanism of action of the antibiotic vancomycin is inhibition of cell wall synthesis. inhibition of nucleic acid synthesis. disruption of cytoplasmic membranes. inhibition of protein synthesis. inhibition of a metabolic pathway.

inhibition of cell wall synthesis

Which of the following is NOT a direct mode of action of antimicrobial drugs? inhibition of flagella formation inhibition of protein synthesis inhibition of cell wall synthesis inhibition of nucleic acid synthesis

inhibition of flagella formation

Which of the following is NOT a type of side effect exhibited by antimicrobial drugs? disruption of normal microbiota inhibition of host cellular enzymes allergic reactions damage to liver or kidney tissue

inhibition of host cellular enzymes

The mechanism of action of ciprofloxacin is inhibition of protein synthesis. inhibition of a metabolic pathway. inhibition of nucleic acid synthesis. disruption of cytoplasmic membranes. inhibition of cell wall synthesis.

inhibition of nucleic acid synthesis. OR disruption of cytoplasmic membranes.

Methicillin is an example of the beta-lactam class of drugs that inhibits protein synthesis. inhibits nucleic acid synthesis. inhibits metabolic pathways. disrupts cytoplasmic membranes. inhibits cell wall synthesis.

inhibits cell wall synthesis

Which of the following is NOT a target of drugs that inhibit protein synthesis? the enzymatic site of the 50S ribosomal subunit the shape of the 30S ribosomal subunit movement of the ribosome from one codon to the next interference with alanine-alanine bridges the tRNA docking site Submit

interference with alanine-alanine bridges

Which of the following drugs specifically targets cell walls that contain mycolic acid? bacitracin vancomycin isoniazid methicillin penicillin

isoniazid

A microbe resistant to a variety of different antimicrobials is said to have (cross/drug/multiple) resistance.

multiple

The topical drug ________ inhibits protein synthesis in Gram positive bacteria by preventing loading of isoleucine onto tRNA. Mupirocin Ciprofloxacin Tetracycline Amphotericin B Bacitracin

mupirocin

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

narrow-spectrum drug

AZT and Valaciclovir are antiviral nucleoside analogs that interfere with cell membrane component synthesis. cell wall synthesis. viral attachment. nucleic acid synthesis. protein synthesis.

nucleic acid synthesis

If a particular bacterial species is resistant to beta-lactam antibiotics, which of the following might you expect to find inside the bacterial cells? ergosterol porins R plasmids resistance pumps

R plasmids

It is inappropriate to prescribe antibacterial agents to treat colds or flu because these diseases can act synergistically with each other. the microbes involved can develop resistance rapidly. these diseases exhibit cross resistance. these diseases are transmitted by endospores, which are difficult to kill. these diseases are caused by viruses.

these disease are cause by viruses

External infections can be treated by (intramuscular/surface/topical) administration, in which a drug is applied directly to the site of infection.

topical

Selective (action/toxicity/treatment) means that a given antimicrobial agent is more toxic to a pathogen than to the host being treated.

toxicity

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

transduction

Antisense nucleic acids interfere with protein synthesis. Antisense true or false

true

Biofilms contribute to the spread of resistance to antimicrobials. true or false

true

Organs that are commonly affected by drug toxicity include the kidneys and the liver. true or false

true

Some bacterial cells are resistant to a variety of antimicrobials because they actively pump the drugs out of the cell. true or false

true

There are relatively few antifungal medications available compared to antibacterial drugs. true or false

true

Which of the following is NOT a beta-lactam antibiotic? penicillin G cephalothin methicillin vancomycin

vancomycin

Antimicrobials known as "attachment antagonists" are particularly useful for preventing bacterial protein synthesis. biofilm formation. cell membrane synthesis. nucleic acid synthesis. virus infection.

virus infection

The first antimicrobial widely available for treatment of bacterial infections was a synthetic compound which interfered with bacterial cell wall synthesis. was an antimetabolic analog. disrupted cytoplasmic membranes. was a nucleotide analog. was an attachment antagonist.

was an anti metabolic analog

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? Whether or not hand sanitizer is available at the changing table 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 the changing table is visibly soiled

whether or not the changing table is visibly soiled

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

yeast

Which of the following antimicrobial drugs would likely be useful to treat a methicillin-resistant Staphylococcus aureus infection because it effectively blocks initiation of translation? praziquantel oxazolidinones mupirocin azoles

oxazolidinone

Which antibiotic is overcome by beta-lactamases? Tetracycline Sulfonamide Penicillin Tetracycline, Penicillin, and Sulfonamide are all affected by beta-lactamase.

penicillin

Why would an efflux pump for penicillin located on a bacterial cell membrane not be effective at providing resistance to the drug? The efflux pumps would not stop penicillin from blocking metabolic pathways. There are fewer efflux pumps on the cell membrane. The cell membrane is the target of penicillin. Penicillin disrupts the cell wall, which is located outside of the cell membrane.

penicillin disrupts the cell wall which is located outside of the cell membrane

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

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. protein cell wall carbohydrate cell wall carbohydrate glycocalyx steroid lipid cytoplasmic membrane phospholipid cytoplasmic membrane peptidoglycan cell wall

peptidoglycan cell wall

Most drugs that inhibit the synthesis of the cell wall act by preventing the formation of alanine-alanine bridges. blocking the secretion of cell wall molecules from the cytoplasm. preventing the cross-linkage of NAM subunits. disrupting the formation of the mycolic acid layer of the cell wall. preventing the formation of ?-lactamases

preventing the cross-linkage of NAM subunits

The tetracyclines interfere with nucleic acid synthesis. cell wall synthesis. folic acid synthesis. cell membrane component synthesis. protein synthesis.

protein synthesis

The therapeutic range of an antimicrobial is the... ratio of the dose a patient can tolerate to the effective dose. range of microorganisms the antimicrobial effects. length of time the medication persists in the body after a single dose. range of concentrations at which the antimicrobial is both effective and non-toxic. ratio of the concentration of antimicrobial in the blood to the oral dose.

range of concentrations at which the antimicrobial is both effective and non-toxic.

Which of the following is NOT a possible side effect of antimicrobial therapy? resistance allergies disruption of normal microbiota toxicity

resistance

An antimicrobial disk on a Kirby-Bauer plate that shows no zone of inhibition indicates that the microbe being tested is __________ to the drug. synergistic intermediate resistant susceptible

resistant

Which of the following drugs inhibits nucleic acid synthesis specifically in most bacteria? 5-fluorocytosine actinomycin tetracycline rifampin fluoroquinolones

rifampin? Flouroquinolones?

Semisynthetic drugs developed to combat resistance are often called (analog/second generation/synergist) drugs.

second generation

Amoxicillin is very effective for treating infections with Gram-positive bacteria but rarely causes side effects in humans. This is an example of altruism. selective toxicity. antibiotic resistance. a broad-spectrum antimicrobial.

selective toxicity

A compound is extracted from a microbial culture and is modified in the laboratory for use as an oral medication. This product would be a(n) semisynthetic antimicrobial. synthetic antimicrobial. antibiotic. analog. probiotic

semisynthetic antimicrobial

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

silent mutation

Which of the following activities can be shown to increase resistance among microbial populations? 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

taking antibacterial drugs for coral infections

Which of the following groups of drugs can become incorporated into the bones and teeth of a fetus? beta-lactams tetracyclines sulfonamides quinolones aminoglycosides

tetracyclines

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

the ability of the normal flora to outcompete and outgrow pathogens

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

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 the sensitive bacterial cells

The antimicrobial polymyxin... blocks a metabolic pathway. inhibits nucleic acid synthesis. inhibits protein synthesis. disrupts cytoplasmic membranes. inhibits cell wall synthesis.

disrupts cytoplasmic membranes

Pentamidine is an example of an antimicrobial used to treat viral infections. effective against helminths. used to treat bacterial infections. effective against eukaryotes, especially protozoa. used to treat both bacterial and fungal infections.

effective against eukaryotes, especially protozoa

Some bacteria are resistant to antimicrobials due to the activity of ________, which removes many of them. efflux pumps plasmids lipopolysaccharides porins ribosomes

efflux pumps

Antiviral medications frequently block unique (proteins/enzymes/molecules) to prevent production of a new virus.

enzymes

The antifungals known as polyenes interact with ________, a lipid unique to fungus membranes. phospholipid glycolic acid cholesterol ergosterol mycolic acid

ergosterol

Drug-resistant populations of microbes arise when synergy between medications occurs. the patient becomes immune to the drug. resistant cells become numerous in a population due to their greater vigor. exposure to drugs selectively kills sensitive cells, allowing overgrowth of resistant cells. exposure to drugs causes mutations that produce resistance.

exposure to drugs selectively kills sensitive cells, allowing overgrowth of resistant cells.

Because all cells engage in protein synthesis, there are few antimicrobial drugs that selectively inhibit this process. true or false

false

If a subculture of an MIC test grows in an MBC test, the concentration of the drug was bactericidal. True False

false

Nucleic acid analog drugs have no effect on human cell replication function. true or false

false

Paul Erhlich discovered the first antibiotic. true or false

false

The outer membrane of Gram-negative bacteria enables many antimicrobial drugs to enter the cell more easily. true or false?

false

Who discovered the first antimicrobial widely available to the general public? Ehrlich and Waksman Waksman Ehrlich Fleming Domagk

Domagk

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

DNA gyrase

Why is polymyxin only used on the skin? 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 is sensitive to degradation by acid, making oral delivery unsuitable. It has no effect on bacteria that live in the GI tract. It can disrupt the metabolic pathways found in humans.

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.

The abbreviation (MBC/MIC/MID) stands for the smallest amount of a drug that will inhibit the growth and reproduction of a pathogen.

MIC

Which of the following is a primary advantage of semisynthetic drugs? They are not readily absorbed. They must be administered intravenously. They are less stable and consequently have fewer side effects. They are more effective than the unmodified natural antibiotics. They work faster.

They are more effective than the unmodified natural antibiotics.

The following molecules are involved in the biosynthetic pathway that leads to the formation of DNA and RNA; what is their correct sequence in this pathway? a. PABA b. tetrahydrofolic acid c. purine and pyrimidine nucleotides d. dihydrofolic acid a, d, b, c a, b, d, c a, c, d, b a, b, c, d

a,d,b,c

Some bacteria develop resistance to groups of drugs because the drugs are all structurally similar to each other; this is a phenomenon known as (cross/multiple/synergistic) resistance.

cross

Which of the following is NOT associated with microbial mechanisms of resistance? beta-lactamases MfpA protein porins denaturation of proteins

denaturation of proteins

__________ cells would be expected to be the most susceptible to the action of polyene drugs such as amphotericin B, while __________ cells would be the least susceptible. Fungal; bacterial Fungal; human Bacterial; human Bacterial; fungal

fungal; bacterial

How does resistance to drugs spread in bacterial populations? Horizontal gene transfer between bacteria spreads R (resistance) plasmids. Genetic recombination during sexual reproduction. Exposure to drugs alters gene expression in bacteria. Exposure to drugs induces immunity. Exposure to drugs causes mutations in bacterial genes.

horizontal gene transfer between bacteria spreads R (resistance) plasmids.

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

humans and other animal hosts lack peptidoglycan cell walls.

Why do antimicrobial agents active against mycobacteria have to be administered for months or years rather than the typical 10-30 days prescribed to treat other infections? Mycobacteria do not have cell walls. They are too toxic to be used on a more rapid administration schedule. The only available agents are relatively ineffective drugs. Mycobacteria reproduce very slowly.

micro bacteria reproduce very slowly.

A particular microbe gains resistance to gentamicin. You might also expect this microbe to exhibit resistance against __________. chloramphenicol clindamycin streptomycin vancomycin

streptomycin

Which of the following is NOT associated with the work of Paul Ehrlich? the concept of the "magic bullet" the concept of chemotherapy sulfanilamide arsenic compounds

sulfanilamide

A drug is structurally similar to PABA and inhibits folic acid synthesis. It is most likely a(n) nucleic acid analog. azole. tetracycline. penicillin. sulfonamide.

sulfonamide

What is a superinfection? 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. A superinfection is one that is caused by a eukaryotic organism. A superinfection is caused by a multidrug resistant organism.

superinfection is a disease caused by an organism that is often an opportunist or one that was present in low numbers.

Secondary infections that result from the killing of some of the normal microbiota are called (antagonism/superinfections/resistance).

superinfections

The cooperative activity of drugs such as beta-lactam antibiotics and clavulanic acid, a β-lactamase inhibitor, is known as antimetabolism. chemotherapy. selective toxicity. synergism. cross resistance.

synergism