MICRO Chapter 9/10

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

An antimicrobial that inhibits cell wall synthesis will result in which of the following? A) Cells become more susceptible to osmotic pressure. B) Cells cannot attach to their hosts. C) Ribosomes lose their function. D) The sterols in the cell wall become nonfunctional. E) The replication of cells, including cancer cells, slows down.

Beta-lactam antibiotics have an effect on which of the following types of cells? A) animal cells B) bacterial cells C) fungal cells D) virus-infected cells E) both animal and fungal cells

Which of the following is a primary advantage of semisynthetic drugs? A) They are less stable and consequently have fewer side effects. B) They work faster. C) They have a broader spectrum of action. D) They must be administered intravenously. E) They are not readily absorbed, so they persist longer.

Which of the following drugs specifically targets cell walls that contain mycolic acid? A) vancomycin B) penicillin C) methicillin D) isoniazid E) bacitracin

Which of the following antibiotics disrupts cytoplasmic membrane function in fungi? A) streptomycin B) erythromycin C) tetracycline D) penicillin E) amphotericin B

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

Figure 10.1 represents a Petri plate. The gray area is where bacteria A is growing, the black area is where bacteria B is growing. The white area is a zone where neither organism is growing. What is the best interpretation of what is observed on the plate? A) Bacteria B is producing an antibiotic that inhibits the growth of bacteria A. B) Bacteria A produces a compound that inhibits the growth of bacteria B. C) Bacteria A grows faster than bacteria B. D) Bacterial colony B has depleted the nutrients in the area around the colony. E) No conclusion can be made from this information.

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

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

What does "narrow spectrum antimicrobial" mean? A) The antimicrobial is effective for a very short time. B) The antimicrobial is effective against a few microbes. C) The antimicrobial can only be administered to a small segment of the population. D) The antimicrobial is activated by a specific wavelength in the visible spectrum. E) The antimicrobial is effective on all bacteria but not eukaryotes.

Which of the following groups of drugs can become incorporated into the bones and teeth of a fetus? A) beta-lactams B) aminoglycosides C) quinolones D) tetracyclines E) sulfonamides

Which of the following can result when antibiotic therapy disrupts the normal microbiota? A) anaphylactic shock B) black hairy tongue C) pseudomembranous colitis D) thrush E) both pseudomembranous colitis and thrush

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) A) antibiotic. B) analog. C) semisynthetic antimicrobial. D) synthetic antimicrobial. E) probiotic.

β-lactamase production is an example of which of the following types of resistance? A) alteration of the target of the drug B) inactivation of the drug C) change in the permeability of the drug D) overproduction of an enzyme in a key metabolic pathway E) removal of the drug via a pump

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

Most drugs that inhibit the synthesis of the cell wall act by A) preventing the cross-linkage of NAM subunits. B) blocking the secretion of cell wall molecules from the cytoplasm. C) preventing the formation of alanine-alanine bridges. D) disrupting the formation of the mycolic acid layer of the cell wall. E) preventing the formation of β-lactamases.

Most broad-spectrum antibiotics act by A) inhibiting the synthesis of the cell wall. B) inhibiting protein synthesis. C) inhibiting nucleic acid synthesis. D) inhibiting metabolic pathways. E) disrupting the cytoplasmic membrane.

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

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

Which of the following steps in the folic acid synthesis pathway is specifically inhibited by sulfonamides? A) the conversion of tetrahydrofolic acid to PABA B) the conversion of PABA to dihydrofolic acid C) the conversion of dihydrofolic acid to tetrahydrofolic acid D) the conversion of PABA to tetrahydrofolic acid E) the conversion of dihydrofolic acid to PABA

Which of the following drugs inhibits nucleic acid synthesis specifically in most bacteria? A) fluoroquinolones B) actinomycin C) rifampin D) tetracycline E) 5-fluorocytosine

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

Some bacteria are resistant to antimicrobials due to the activity of ________, which removes many of them. A) plasmids B) porins C) efflux pumps D) lipopolysaccharides E) ribosomes

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

Who discovered the first antimicrobial widely available to the general public? A) Domagk B) Ehrlich C) Fleming D) Waksman E) Ehrlich and Waksman

Which of the following statements is TRUE of selective toxicity? A) Selective toxicity takes advantage of structural differences between host and pathogen. B) To be effective, an antimicrobial agent must be more toxic to the patient than the pathogen. C) Selective toxicity takes advantage of metabolic differences between host and pathogen. D) Antimicrobial agents must target structural differences between host and pathogen and be more toxic to the patient than the pathogen. E) Selective toxicity takes advantage of structural and/or metabolic differences between host and pathogen.

Antimicrobials that block protein synthesis by binding to the mRNA are A) aminoglycosides. B) antisense nucleic acids. C) macrolides. D) beta-lactams. E) nucleic acid analogs.

A "zone of inhibition" is associated with which of the following tests used to determine the efficacy of antibiotics? A) Etest B) diffusion susceptibility test C) broth dilution test D) both the Etest and diffusion susceptibility test E) both the broth dilution and the MBC tests

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

Which of the following interferes with cell wall synthesis by blocking alanine bridge formation? A) beta-lactams B) cycloserine C) bacitracin D) vancomycin E) both cycloserine and vancomycin

Disruption of the normal microbiota can result in infections caused by which of the following microbes? A) Mycobacterium B) Candida albicans C) Clostridium difficile D) both Mycobacterium and Clostridium difficile E) Candida albicans, Mycobacterium, and Clostridium difficile

The antimicrobials called quinolones act by A) disrupting cytoplasmic membranes. B) inhibiting cell wall synthesis. C) inhibiting DNA replication. D) inhibiting a metabolic pathway. E) inhibiting protein synthesis.

The mechanism of action of the antibiotic vancomycin is A) inhibition of protein synthesis. B) inhibition of cell wall synthesis. C) inhibition of nucleic acid synthesis. D) inhibition of a metabolic pathway. E) disruption of cytoplasmic membranes.

The tetracyclines interfere with A) protein synthesis. B) cell wall synthesis. C) cell membrane component synthesis. D) nucleic acid synthesis. E) folic acid synthesis.

Pentamidine is an example of an antimicrobial A) used to treat bacterial infections. B) effective against helminths. C) used to treat viral infections. D) effective against eukaryotes, especially protozoa. E) used to treat both bacterial and fungal infections.

The mechanism of action of erythromycin is A) inhibition of protein synthesis. B) inhibition of cell wall synthesis. C) inhibition of nucleic acid synthesis. D) inhibition of a metabolic pathway. E) disruption of cytoplasmic membranes.

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

The antimicrobial polymyxin A) inhibits protein synthesis. B) inhibits nucleic acid synthesis. C) blocks a metabolic pathway. D) disrupts cytoplasmic membranes. E) inhibits cell wall synthesis.

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

Paul Erhlich coined the term antibiotics for the "magic bullet" antimicrobials he pursued.

Antisense nucleic acids interfere with protein synthesis.

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

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

Biofilms contribute to the spread of resistance to antimicrobials.

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

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

Medications administered intravenously can provide much higher effective concentrations than other delivery methods.

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

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

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

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

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

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

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

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

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

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.

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

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

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

Slow freezing is more damaging to microbial cells than quick freezing. True False

Aseptic means A. free of all microbes. B. sanitized. C. sterile. D. clean. E. free of pathogens.

Silvadene, a topical treatment for burns, contains 1% silver. What category of chemical control agent is in Silvadene? A. surfactants B. halogens C. oxidizing agents D. aldehydes E. heavy metals

Refrigeration is an effective germicidal method. True False

A chemical used to reduce potential pathogens on the skin is a(n) A. degermer. B. antiseptic. C. sanitizer. D. sterilizing agent. E. disinfectant.

Desiccation, a time-honored method of preserving food, is effective because the A.freezing step of the process kills microbes. B.salt concentration is too low to support metabolic function. C.UV light used in the process of sun drying penetrates effectively. D. heat of the process kills microbes. E. water content is too low to support metabolic function.

The decimal reduction time is the time required to kill all the microbes in a given sample. True False

Which of the following describes flash pasteurization? heating at 72°C for 15 seconds heating at 63°C for 30 minutes heating at 134°C for one second passing liquid through steam at 140°C heating at 72°C for 15 minutes

Why are endospores used to measure the effectiveness of autoclave sterilization? A. Endospores are very simple structures and easy to detect. B. Endospores are composed of all the molecules found in living cells. C. Endospores are easy to store in the lab until needed. D. Endospores of different bacteria are destroyed at different temperatures and can be used to calibrate autoclave temperatures. E. Endospores are very hard to kill.

Certain bacilli undergo snapping division, causing them to create arrangements that look as if they are stacked. This is called a____________ arrangement. A. tetrad B. v shape C. palisade D. sarcina

"strepto" means cluster True False

Beta-lactam antibiotics have an effect on which of the following types of cells? A. both animal and fungal cells B. bacterial cells D. animal cells E. fungal cells

Organs that are commonly affected by drug toxicity include the kidneys and the liver. True False

The antimicrobial polymyxin A. inhibits protein synthesis. B. disrupts cytoplasmic membranes. C. blocks a metabolic pathway. D. inhibits cell wall synthesis. E. inhibits nucleic acid synthesis.

Paul Erhlich coined the term antibiotics for the "magic bullet" antimicrobials he pursued. True

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

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

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

Which of the following drugs specifically targets cell walls that contain mycolic acid? A. penicillin B. vancomycin C. isoniazid D. methicillin E. bacitracin

What is the first thing you need to do when looking through the ocular on the microscope? A. adjust the ocular lens B. adjust the stage C. observe the location of the slide D. turn on the light