Exam 3 - 8, 9, 10 (MC)
The enzymes that can proofread replicating DNA, detect incorrect bases, excise them, and correctly replace them are ... a. DNA polymerases b. DNA ligases c. DNA helicases d. DNA primases e. DNA gyrases
DNA polymerases
The use of chemical agents directly on exposed body surfaces to destroy or inhibit vegetative pathogens is ... A. disinfection. B. sterilization. C. antisepsis. D. sanitization.
antisepsis
Polymyxins
disrupt bacterial cell membrane
Quinolones (Fluoroquinolones)
inhibit bacterial DNA synthesis
State the mechanism of action for the following antifungal agents Echinocandins
inhibit fungal cell wall synthesis
State the mechanism of action for the following antifungal agents Azoles
inhibit fungal ergosterol synthesis
All of the following disrupt the cytoplasmic membrane except ... A. detergents B. quaternary ammonium compounds C. high concentration phenols D. iodine.
iodine
Which of the following is a narrow-spectrum drug used to treat cases of tuberculosis? a. sulfanilamide b. ciprofloxacin c. isoniazid d. tetracycline e. polymyxin
isoniazid
Which of the following two drugs target bacterial cell membranes? (select all that apply) a. trimethoprim b. polymyxin c. penicillin d. daptomycin e. ciprofloxacin
polymyxin daptomycin
The process of using a cleansing technique to mechanically remove and reduce microorganisms and debris to safe levels is ... A. disinfection B. sterilization C. antisepsis D. sanitization
sanitization
DNA polymerase III ... A. is needed for adding nucleotides during mRNA synthesis. B. synthesizes new DNA only in the 5' to 3' direction. C. cannot add nucleotides to the lagging strand. D. synthesizes an RNA primer.
synthesizes new DNA only in the 5' to 3' direction
What cell wall disrupting drug is used in cases of penicillin and methicillin resistance? A. penicillin G B. vancomycin C. tetracycline D. erythromycin E. isoniazid
vancomycin
The easiest microbial forms to kill or inhibit are ... A. prions. B. vegetative bacteria and fungi. C. endospores. D. protozoan cysts. E. mycobacteria and staphylococci.
vegetative bacteria and fungi
Select the methods of antimicrobial susceptibility testing that can be used to determine minimum inhibitory concentrations (MICs). A. Kirby-Bauer test (disk diffusion method) B. E-test C. Tube dilution test
- E-test Tube - dilution test
Select those statements that describe features of transcription and translation that are found in eukaryotes but not in bacteria. A. Transcription and translation both occur in the cytoplasm. B. Genes are interrupted by intervening sequences. C. mRNA is ready to translate directly as it is produced by RNA polymerase. D. A tail of multiple adenine ribonucleotides is added to the mRNA transcript. E. mRNA transcript must pass through pores to get out of the nucleus. F. RNA transcript is processed to remove introns and splice together exons. G. Genes are organized into functional units called operons.
- Genes are interrupted by intervening sequences. - A tail of multiple adenine ribonucleotides is added to the mRNA transcript. - mRNA transcript must pass through pores to get out of the nucleus. - RNA transcript is processed to remove introns and splice together exons.
Select 3 of the main cellular targets of the clinically useful anti-fungal drugs: (choose all that apply) a. inhibit protein synthesis by targeting the 70S ribosome b. bond to and disrupt ergosterol in the cell membrane c. blocking entry of the microbe into host cells d. interfere with the action of DNA helicases (e.g. DNA gyrase) so that cells cannot replicate or transcribe DNA e. inhibit protein synthesis by targeting the 80S ribosome f. inhibit enzymes for ergosterol synthesis g. inhibit enzymes for the synthesis of cell wall chitin and glucans
- bond to and disrupt ergosterol in the cell membrane - inhibit enzymes for ergosterol synthesis -inhibit enzymes for the synthesis of cell wall chitin and glucans
Suppose you applied a disinfectant to a surface containing 1,000,000 E. coli cells and after 1 minute you determined that there are 100,000 live bacteria remaining. How many viable bacteria would you expect to be remaining if you had allowed the treatment to go on for an additional 2 minutes (so 3 minutes total)? a. 500 b. 10,000 c. 50,000 d. 1,000 e. 0
1,000
The most efficient sterilizing conditions in a steam autoclave are ... A. 121°C at 15 psi for 15 minutes. B. 63°C for 30 minutes. C. 160°C for 2 hours. D. 71.6°C for 15 seconds. E. 100°C for 30 minutes.
121°C at 15 psi for 15 minutes
If the mRNA codon for alanine is 5'-GCA-3', then the correct anticodon would be: A. 3'-GCA-5' B. 3'-CGT-5' C. 3'-ACG-5' D. 3'-CGU-5' E. 3'-UGC-5'
3'-ACG-5'
Below is part of a nucleotide sequence from a gene at the transcriptional start site. What is the mRNA sequence that would be made from transcription of this gene? promoter -->> 5' - AAC GTT CTT AAA CCC ATA - 3' 3' - TTG CAA GAA TTT GGG TAT - 5' a. 5' - UUG CAA GAA UUU GGG UAU - 5' b. 5' - AAC GUU CUU AAA CCC AUA - 3'
5' - AAC GUU CUU AAA CCC AUA - 3'
Where is the Shine-Dalgarno sequence located within a prokaryotic mRNA? a. ORF b. intron c. poly A tail d. 5' UTR e. 3' UTR
5' UTR
Below is a nucleotide sequence of the sense strand (also known as the coding strand or the positive strand) of DNA for a gene. Which would represent the correct mRNA made from this gene? a. 5'- C G A T A C G G A C T C -3' b. 5'- G C T U T G C C T G U G -3' c. 5'- C G A U A C G G A C U C -3' d. 5'- G C T U T G C C U G A G -3' e. 5'- A C U A U A C C U A U A -3'
5'- C G A U A C G G A C U C -3'
Below is a nucleotide sequence of the sense strand (also known as the coding strand or the positive strand) of DNA for a gene. Which would represent the correct mRNA made from this gene? 5'- C G A T A C G G A C T C -3 A. 5'- A C U A U A C C U A U A -3' B. 5'- C G A U A C G G A C U C -3' C. 5'- G C T U T G C C T G U G -3' D. 5'- G C T U T G C C U G A G -3
5'- C G A U A C G G A C U C -3'
Which of the following statements regarding alcohols is FALSE? a. A 70% alcohol solution is an effective disinfectant and antiseptic. b. Alcohol solutions can denature proteins. c. Alcohol solutions kill endospores and thus can be used to sterilize medical instruments. d. Alcohols can disrupt a cell's phospholipid bilayer. e. One limitation to the use of alcohols is their fast rate of evaporation.
Alcohol solutions kill endospores and thus can be used to sterilize medical instruments.
Alcohols ... A. dissolve membrane lipids at concentrations of between 60-80%. B. can be used for disinfection or antisepsis C. are skin degerming agents D. are limited in effectiveness due to rapid evaporation E. All of the choices are correct.
All of the choices are correct
Based on its mode of action, which of the following microbes are targeted by alcohol-based hand cleaners? a. bacteria b. All of the choices are correct. c. viruses d. protozoa e. fungi
All of the choices are correct
Which of the following is NOT a correctly matched term and definition? a. Antibiotic : any drug used for treatment of infectious disease b. Chemotherapeutic drug : any drug used in the treatment, relief, or prophylaxis of a disease c. Synthetic drug : a drug produced entirely by chemical reactions carried out in a laboratory d. Semisynthetic drug : a drug chemically modified after being isolated from natural sources e. Prophylaxis : use of a drug to prevent infection of a person at risk
Antibiotic : any drug used for treatment of infectious disease
Which of the following antibiotic modes of action would you expect to have the least toxic effect on a human cell? Explain your choice. Antibiotic A: inhibits DNA polymerase Antibiotic B: inhibits enzymes for the synthesis of phospholipids Antibiotic C: inhibits enzymes for the synthesis of peptidoglycan
Antibiotic B: inhibits enzymes for the synthesis of phospholipids
Look at the following Table of results from a Disk-Diffusion test. In general, which antibiotic was the most effective against this bacteria species? Antibiotic Zone of Inhibition (mm) A 1.0 B 3.3 C 12.4 D 19.6
Antibiotic D
Which is correct regarding the rate of microbial death? A. Cells die at increasingly greater rates. B. Only older cells die in a culture. C. Cells in a culture die at a constant logarithmic rate. D. Upon contact with the control agent, all cells die at one time. E. Cells become metabolically inactive, but are never killed.
Cells in a culture die at a constant logarithmic rate
________________ is a type of biguanide commonly used in hand scrubs, obstetrical washes, and prepping skin for surgery. a. Chlorhexidine b. O-phenylphenol c. Carbolic acid d. Formalin e.Soap
Chlorhexidine
The enzymes that can proofread replicating DNA, detect incorrect bases, excise them, and correctly replace them are ... A. DNA ligases. B. DNA polymerases. C. DNA helicases. D. DNA gyrases.
DNA polymerases
A narrow-spectrum antimicrobial would be an appropriate choice to treat an abscess caused by several different microbe species, including both Gram-negative and Gram-positive bacteria. True or False
False
Which cell can transfer both chromosomal and plasmid genes to a recipient cell by conjugation? A. F+ cell B. F- cell C. Hfr cell
Hfr cell
Due to the absence of proofreading mechanisms in RNA polymerases, the mutation rate in replicating RNA genomes is higher than that for DNA genomes. This is one reason for the high rate of mutation in ... a. Influenza viruses b. Adenoviruses c. Streptococcus mutans d. Vibrio cholerae
Influenza viruses
What is the mechanism by which lactose regulates the expression of the lac operon? a. Lactose binds to an allosteric/regulatory site on the Lac Activator protein and activates the protein so that it can bind to the activator binding site and repress transcription. b. Lactose binds to an allosteric/regulatory site on the Lac Repressor protein and inactivates the protein so that it cannot bind to the operator site and repress transcription any longer. c. Lactose binds to an allosteric/regulatory site on the Lac Repressor protein and activates the protein so that it can bind to the operator site and repress transcription. d. Lactose binds directly to the RNA polymerase and inactivates the protein so that it cannot initiate transcription any longer.
Lactose binds to an allosteric/regulatory site on the Lac Repressor protein and inactivates the protein so that it cannot bind to the operator site and repress transcription any longer.
A clinical microbiologist makes serial dilutions of several antimicrobials in broth, and then incubates each drug dilution series with a standard amount of a patient's isolated pathogen. What test is this microbiologist setting up? A. Kirby-Bauer B. antibiogram C. E-test D. MIC
MIC
From the list below, choose the two most resistant microbial forms. A. Mycobacterium spp. B. Vegetative bacteria C. Fungal spores D. Endospores E. Enveloped viruses
Mycobacterium spp Endospores
__________ was the first antibiotic ever discovered. It is produced by a fungus. a. Streptomycin b. Chrysogenium c. Cephalosporin d. Ciprofloxacin e. Penicillin
Penicillin
Select each chemical control method below that denatures/damages proteins as one of its mechanism(s) of action: (choose all that apply) a. Phenolics and Bisphenols b. Soap c. Alcohols d. Formaldehyde e. Chlorhexidine
Phenolics and Bisphenols Alcohols Formaldehyde Chlorhexidine
Which of the following statements is FALSE? a. In bacteria, transcription and translation are coupled; that is, translation begins while the mRNA is still being synthesized. b.DNA polymerase synthesizes a DNA strand in the 5′ to 3′ direction using a template strand of DNA. c.RNA polymerase synthesizes an RNA strand in 3′ to 5′ direction using a template strand of DNA. d.Transcription differs from DNA replication in that only one of the two DNA strands will serve as the template strand for that gene. e. In double-stranded DNA, one strand runs in the 5' to 3' direction and the opposite strand runs in the 3' to 5' direction.
RNA polymerase synthesizes an RNA strand in 3′ to 5′ direction using a template strand of DNA.
Select each chemical control method below that disrupts cell membranes (lipid bilayers) as one of its mechanism(s) of action: (choose all that apply) a. Surfactants b. Hydrogen peroxide c. Chlorine d. Alcohols e. Phenolics and Bisphenols
Surfactants, Alcohols, Phenolics and Bisphenols
Erythromycin is a macrolide antibiotic. Imagine you have an erythromycin-sensitive species of bacteria. Select plausible scenarios in which a population of these bacteria could become resistant to erythromycin. (choose all that apply) a . The gene encoding DNA gyrase could incur a nonsense mutation that leads to loss of function of the enzyme rendering the bacteria impermeable to the drug. b. The bacterium could acquire an existing erythromycin-resistance gene via horizontal gene transfer from another species. That gene maybe an erythromycin efflux pump that would actively transport the drug out of the cell. c. The bacterium could acquire an existing penicillin-resistance gene via horizontal gene transfer from another species. That gene maybe one encoding a penicillinase enzyme that would inactivate the macrolide drug. d. The gene encoding the target 70S ribosomal protein could incur a missense mutation that lowered the affinity between the target protein and the drug while retaining the function of the protein.
The bacterium could acquire an existing erythromycin-resistance gene via horizontal gene transfer from another species. That gene maybe an erythromycin efflux pump that would actively transport the drug out of the cell. The gene encoding the target 70S ribosomal protein could incur a missense mutation that lowered the affinity between the target protein and the drug while retaining the function of the protein.
In semiconservative DNA replication at a replication fork, these two constraints explain why one new strand can be made in a continuous manner (the leading strand) while the other new strand is made in a discontinuous manner (the lagging strand): (select the 2 that apply) a. DNA polymerase has a proofreading activity and can remove incorrect bases that may be added to the growing DNA polymer. b. DNA is a polymer made up of nucleotides. c. The two strands in a dsDNA molecule are antiparallel (run in opposite directions) (5´ to 3´ for one, and 3´ to 5´ for the other). d. DNA polymerase can only add bases to the 3´ end of a nucleic acid strand using a complementary DNA strand as a template.
The two strands in a dsDNA molecule are antiparallel (run in opposite directions) (5´ to 3´ for one, and 3´ to 5´ for the other). DNA polymerase can only add bases to the 3´ end of a nucleic acid strand using a complementary DNA strand as a template.
Presence of the amino acid tryptophan represses expression of the tryptophan (trp) operon because tryptophan binds to the ... a. Trp Repressor protein, inhibiting it from binding to the operator. b. Trp Activator protein, inhibiting it from binding to the enhancer. c. Trp Activator protein, activating it to bind to the enhancer. d. Trp Repressor protein, activating it to bind to the operator.
Trp Repressor protein, activating it to bind to the operator
__________ radiation excites atoms to a higher energy state within molecules such as DNA that then leads to the formation of pyrimidine dimers. a. Ionizing b. Gamma c. Infrared d. Ultraviolet e. X ray
Ultraviolet
Which of the following antibiotic classes does NOT target bacterial 70S ribosomes? a. Vancomycin b. Macrolides c. Tetracyclines d. Aminoglycosides e. Clindamycin
Vancomycin
Phase variation describes when bacteria turn on or off a complement of genes that leads to obvious phenotypic changes in the bacteria. Which of the following is an example of phase variation? a. With Escherichia coli, the repression of the lac operon in response to lactose. b. With Neisseria gonorrhoeae, the changing of expression of different cell surface Opa and pili proteins. c. With Influenza viruses, random mutations that occur during virus replication leading to antigenic drift. d. With Staphylococcus aureus, the existence of different antibiotic resistant strains.
With Neisseria gonorrhoeae, the changing of expression of different cell surface Opa and pili proteins.
As a group, the semisynthetic penicillins show some advantages over the natural penicillin. These advantages can include ... (choose all that apply) a. being able to kill fungal and protozoan cells b. acid-stability and improved absorption c. having a broadened spectrum of activity (particularly against Gram-negative bacteria) d. being penicillinase resistant
acid-stability and improved absorption having a broadened spectrum of activity (particularly against Gram-negative bacteria) being penicillinase resistant
HEPA filters are used to remove microbes from ... A. air. B. liquids. C. human tissues. D. medical instruments.
air
Important characteristics of antimicrobial drugs include ... A. low toxicity for human tissues. B. high toxicity against microbial cells. C. do not cause serious side effects in humans. D. stable and soluble in body tissues and fluids. E. All of the choices are correct.
all the choices are correct
Three consecutive bases (codon) in the DNA of a gene represent the code for one ... A. protein. B. nucleotide. C. amino acid. D. purine.
amino acid
Diseases caused by Gram-negative bacilli are often treated with ... A. penicillin G. B. vancomycin. C. aminoglycosides. D. synercid. E. isoniazid.
aminoglycosides
The betadine swab before blood donation is an example of ... A. antisepsis. B. disinfection. C. sterilization. D. decontamination. E. sanitization.
antisepsis
The use of chemical agents directly on exposed body surfaces to destroy or inhibit vegetative pathogens is ... a. disinfection b. antisepsis/degermation c. sterilization d. sanitization/decontamination
antisepsis/degermation
You utilize an alcohol-based hand cleaner with friction rub when your hands are not visibly dirty. Which of the following terms appropriately describes the type of antimicrobial control provided by alcohol-based hand cleaners? a. antisepsis/degermation b. decontamination c. disinfection d. sterilization
antisepsis/degermation
There are fewer antifungal, antiprotozoan, and antihelminth drugs compared to antibacterial drugs because fungi, protozoa, and helminths ... a. have cells with smaller genomes and thus fewer encoded targets compared with bacteria. b. are not affected by any antimicrobials. c. are parasites only found growing inside of human cells. d. are so much more similar to human cells that drug selective toxicity is more difficult. e. do not cause any significant human infections.
are so much more similar to human cells that drug selective toxicity is more difficult.
In our microbiology class lab, after you place your bacterial cultures in the biohazard trash container, the trash is sterilized by _____________. a. exposing it to UV light for 30 minutes. b. freezing it for 8 hours. c. autoclaving at 121°C (15 psi) for 20 minutes. d. heating in a dry oven at 63°C for 30 minutes. e. pouring alcohol on it.
autoclaving at 121°C (15 psi) for 20 minutes
Which of the following antimicrobial agents would be recommended for use against fungal infections? a. Isoniazid b. Azoles c. Aminoglycosides d. Acyclovir e. Quinine
azoles
Which type of microbe has the highest resistance to physical/chemical growth control agents? a. naked viruses b. fungal spores c. vegetative yeast d. bacterial endospores e. protozoan cysts
bacterial endospores
Placing organisms in a refrigerator at 4°C is ... a. sterilization b. bacteriostatic c. bacteriocidal d. decontamination
bacteriostatic
Explain why moist heat is more effective than dry heat for sterilization: a. because water facilitates the denaturation of carbohydrates b. because water is a universal solvent c. because water facilitates the denaturation of proteins d. because water allows for higher temperatures
because water facilitates the denaturation of proteins
Methicillin resistant Staphylococcus aureus (MRSA) express a mutant transpeptidase (PBP2a) that retains its peptidoglycan synthesis activity but is unaffected by penicillin family antibiotics. This is an example of which of the following mechanisms of drug resistance? a. binding sites for the drug onto target is decreased. b. drug is eliminated from cell due to efflux pump. c. permeability or uptake of the drug is decreased d. new enzymes are synthesized that degrade/inactivate the drug e. alternative metabolic pathways are used
binding sites for the drug onto target is decreased
Which of the following cannot be disinfected using UV radiation? A. center of solid objects B. liquids C. surfaces D. air
center of solid objects
The cell's essential genes (housekeeping genes), such as FtsZ (tubulin-like), aldolase, catalase, ATP synthase, and RNA polymerase would be located where in the cell's genome? a. chromosome b. prophage c. transposon d. plasmid
chromosome
Among the prokaryotic microorganisms, various genomes can include: (select all that apply) A. chromosomes. B. plasmids. C. mitochondrial DNA. D. chloroplast DNA.
chromosomes, plasmids
With regard to antimicrobial therapeutics, selective toxicity refers to ... a. damage to the target organisms but not host cells. b. damage to all pathogenic organisms. c. damage to prokaryotic cell membranes. d. damage to nucleic acids.
damage to the target organisms but not host cells
Exposing bacteria to a chemical or radiation that __________ can increase the rate of mutation in that population. a. cannot be metabolized b. dissolves lipids c. denatures proteins d. damages DNA
damages DNA
What is the primary mode of action of ionizing radiation (gamma rays, X-rays)? a. damages DNA/RNA via formation of oxygen free radicals reacts with and cross-links proteins b. damages DNA/RNA by being absorbed by pyrimidines c. disrupts phospholipid bilayers d. denatures proteins
damages DNA/RNA via formation of oxygen free radicals
What are the 3 general modes/mechanisms of action exerted by the physical and chemical agents of microbial growth control? a. damaging/denaturing/disrupting polysaccharides b. damaging/denaturing/inhibiting proteins c. damaging/inducing mutations/preventing synthesis of nucleic acids d. damaging membrane lipids/altering membrane permeability e. damaging/disrupting the cell cytoplasm
damaging/denaturing/inhibiting proteins damaging/inducing mutations/preventing synthesis of nucleic acids damaging membrane lipids/altering membrane permeability
Boiling water is a means of ... a. antispesis b. disinfection c. cleaning d. sterilization
disinfection
Boiling water is a means of ... A. sterilization B. disinfection C. antisepsis D. all of the above
disinfection
The use of a physical or chemical process to destroy vegetative pathogens is ... A. disinfection. B. sterilization. C. antisepsis. D. sanitization.
disinfection
State the mechanism of action for the following antifungal agents Macrolide polyenes
disrupt fungal cell membrane
Cationic Detergents (Quaternary Ammonium compounds or Quats) like benzalkonium chloride are antimicrobial because they ... a. damage DNA b. react with DNA/RNA c. disrupt membranes only d. disrupt proteins and membranes
disrupt proteins and membranes
Which of the following mechanisms of antibiotic resistance act specifically by penicillinase on penicillins and cephalosporins? a. binding sites for the drug onto target is decreased. b. drug is eliminated from cell due to efflux pump. c. permeability or uptake of the drug is decreased d. alternative metabolic pathways are used e. enzymes are synthesized that degrade/inactivate the drug
enzymes are synthesized that degrade/inactivate the drug
Which of the following terms would best describe a mutation that leads to the deletion of two bases from a DNA protein-coding sequence? A. frame shift mutation B. back mutation C. silent mutation D. point mutation
frame shift mutation
Ketoconazole, fluconazole, clotrimazole, miconazole are broad-spectrum azoles used to treat what type of infections? A. bacterial B. fungal C. protozoan D. helminthic
fungal
Which of the following drugs blocks binding of HIV to host cell receptors? A. AZT B. acyclovir C. nevirapine D. fuzeon
fuzeon
Each ________ is a specific segment of the genome (DNA) with the code for production of one functional product. a. promoter b. intron c. gene d. origin
gene
Select 2 of the physical agents of microbial growth control: (choose all that apply) a. chlorine b. heat c. detergent d. radiation e. phenolics
heat, radiation
Acyclovir is used to treat ... A. influenza A virus. B. HIV. C. herpes simplex virus. D. respiratory syncytial virus. E. hepatitis C virus.
herpes simplex virus.
In transformation, transduction or conjugation, what process is necessary for the donor chromosomal DNA to become a part of the recipient cell's chromosome? a. conjugation b. transcription c. glycolysis d. gene conversion e. homologous DNA recombination
homologous DNA recombination
Select those items in which microbial growth is controlled by means of osmotic pressure A. honey B. apple cider C. salt-cured meats D. milk E. yogurt F. jellies
honey, salt-cured meats, yogurt
Vancomycin-resistant Staphylococcus aureus (VRSA) acquired vancomycin resistance genes from previously known resistant Enterococcus species in patients infected with both pathogens. The evolution of VRSA is likely to have occurred through ... a. genetic engineering b. horizontal gene flow (recombination) c. vertical gene flow (mutation) d. phase variation
horizontal gene flow (recombination)
Which of the following can be used as an antiseptic at low concentrations (3% solution) and as a sterilant at high concentration (35% solution)? a. phenol b. soap c. chlorhexidine d. hydrogen peroxide e. alcohol
hydrogen peroxide
Which of the following can be used as an antiseptic at low concentrations (3% solution) and as a sterilant at high concentration (35% solution)? A. alcohol B. phenol C. hydrogen peroxide D. chlorhexidine E. soap
hydrogen peroxide
Which of the following is incorrect about termination codons? A. where the bond between the final tRNA and the finished polypeptide chain is broken B. include AUG C. include UAA, UAG, and UGA D. do not have corresponding tRNA E. can also be called nonsense codons
include AUG
Carbapenems
inhibit bacterial cell wall synthesis
Cephalosporins
inhibit bacterial cell wall synthesis
Penicillins
inhibit bacterial cell wall synthesis
Vancomycin
inhibit bacterial cell wall synthesis
sulfonamides (sulfa drugs)
inhibit bacterial folic acid synthesisa
Aminoglycosides
inhibit bacterial protein synthesis
Macrolides
inhibit bacterial protein synthesis
Tetracyclines
inhibit bacterial protein synthesis
State the mechanism of action for the following antifungal agents Allylamines
inhibit fungal cell wall synthesis
The main classes of antiviral drugs have modes of action that include all of the following EXCEPT: A. block virus penetration into host cell B. inhibit the virus ribosome C. block transcription D. inhibit DNA synthesis E. block virus release
inhibit the virus ribosome
Select the 3 major mechanisms by which antiviral medications work. (choose all that apply) a. inhibiting the viral ribosome b. inhibiting the assembly and release of virions c. inhibiting genome replication and transcription d. preventing viral cell wall synthesis e. preventing entry of the virus into the host cell
inhibiting the assembly and release of virions inhibiting genome replication and transcription preventing entry of the virus into the host cell
Azidothymidine (AZT) is a nucleotide analog and antiretroviral medication used to prevent and treat HIV/AIDS. The drug works by ... a. inhibiting virion fusion with the host cell b. inhibiting the maturation of the virus proteins c. inhibiting attachment of virions to the host cell d. inhibiting virus nucleic acid synthesis
inhibiting virus nucleic acid synthesis
An antiviral that is a guanine analog would have an antiviral mode of action that ... A. blocks penetration. B. inhibits translation. C. inhibits DNA synthesis. D. blocks maturation.
inhibits DNA synthesis
Daptomycin
inhibits bacterial cell membrane synthesis
Tetracycline is referred to as a broad spectrum antibiotic because it ... a. inhibits both fungi and bacteria. b. is both bacteriostatic and bacteriocidal. c. inhibits many Gram-positive and Gram-negative bacteria. d. is produced by a variety of microorganisms. e. inhibits a wide spectrum of physiological activities in the bacterial cell.
inhibits many Gram-positive and Gram-negative bacteria
isoniazid
inhibits mycolic acid synthesis in mycobacterium tuberuculosis
Select the 5 main cellular targets for the clinically useful antibiotics against bacteria: (choose all that apply) a. interfere with the action of DNA helicases (e.g. DNA gyrase) so that cells cannot replicate or transcribe DNA b. inhibit enzymes for sterol synthesis c. disrupt cell membranes by targeting bacteria-specific d. phospholipids (e.g. LPS, phosphatidylglycerol) d. bond to and disrupt ergosterol in the cell membrane e. inhibit protein synthesis by targeting the 70S ribosome f. blocking cell wall synthesis (e.g. PGN, LPS, mycolic acid) g. inhibit enzymes for folic acid synthesis i. blocking entry of the microbe into host cells
interfere with the action of DNA helicases (e.g. DNA gyrase) so that cells cannot replicate or transcribe DNA disrupt cell membranes by targeting bacteria-specific phospholipids (e.g. LPS, phosphatidylglycerol) inhibit protein synthesis by targeting the 70S ribosome blocking cell wall synthesis (e.g. PGN, LPS, mycolic acid) inhibit enzymes for folic acid synthesis
The advantage of using ethylene oxide as a sterilant over moist heat sterilization in an autoclave is that ________. a. it can be used to sterilize plastics that would melt in an autoclave b. all of the choices are reasons to preferentially use ethylene oxide as a sterilant c. it kills endospores, whereas the autoclave will only kill vegetative cells d. it is much safer for humans to work with ethylene oxide than to operate an autoclave
it can be used to sterilize plastics that would melt in an autoclave
There are three levels of disinfection: high, intermediate, and low. High-level disinfection is effected with a chemical germicide cleared for marketing as a sterilant by the Food and Drug Administration. For use in this case, the germicide must be able to ... a. kill all microbes, including both vegetative bacteria and bacterial endospores. b. kill fungal spores, certain resistant pathogens, most viruses, but not bacterial endospores. c. kill vegetative bacteria, vegetative fungal cells, and some viruses. d. kill enveloped viruses and most Gram-positive bacteria.
kill all microbes, including both vegetative bacteria and bacterial endospores.
High-level germicides and used for high-level disinfection. For use in this case, the germicide must be able to ... A. kill enveloped viruses and most Gram-positive bacteria B. kill vegetative bacteria, vegetative fungal cells, and some viruses C. kill fungal spores, certain resistant pathogens, most viruses, but not bacterial endospores D. kill all microbes, including both vegetative bacteria and bacterial endospores
kill fungal spores, certain resistant pathogens, most viruses, but not bacterial endospores
Full induction of the lactose (lac) operon requires ... a. lactose present without glucose. b. lactose and arabinose present. c. lactose present. d. lactose and glucose present.
lactose present without glucose
Full induction of the lactose operon requires ... A. lactose present B. lactose and glucose present C. lactose present without glucose D. lactose and arabinose present.
lactose present without glucose
Which newer synthetic drug is used to treat MRSA, VRSA, and VRE infections? A. penicillin G B. clindamycin C. linezolid D. azithromycin
linezolid
Certain types of cell growth media must be sterilized without heating. What other methods could be used to sterilize these types of media? (choose all that apply) a. autoclaving b. boiling/pasteurization c. membrane filtration d. UV irradiation e. gamma irradiation
membrane filtration, gamma irradiation
An antimicrobial drug used to treat a number of anaerobic protozoan and anaerobic bacterial infections is ... a. penicillin b. griseofulvin c. sulfa drugs d. amphotericin B e. metronidazol
metronidazole
Some bacteria have acquired resistance to the antibiotic streptomycin because they have a mutation affecting one of the ribosomal proteins. This mutation has changed the protein so that it still has its normal activity but it no longer can be bound by the drug. This type of mutation is most likely a ... a. frame-shift mutation b. silent mutation c. nonsense mutation d. missense mutation
missense mutation
Some bacteria have acquired resistance to the antibiotic streptomycin because they have a mutation affecting one of the ribosomal proteins. This mutation has changed the protein so that it still has its normal activity but it no longer can be bound by the drug. This type of mutation is most likely a ... A. missense mutation B. silent mutation C. frame-shift mutation D. nonsense mutation
missense mutation
The genome of a bacterium may include all of the following except: a.plasmid b. prophage c. chromosome d. mitochondrial DNA
mitochondrial DNA
Each of the following contributes to emerging drug resistance except ________. a. addition of antibiotics to common household products b. improper use of antibiotics c. multiple drug therapy with drug cocktails d. overuse of antibiotics e. ingestion of antibiotics with animal feed
multiple drug therapy with drug cocktails
Which of the following terms would best describe a mutation that changes a normal codon into a stop codon? a. nonsense mutation b. frame-shift mutation c. silent mutation d. missense mutation
nonsense mutation
All of the following pertain to transcription except ... A. occurs on a ribosome in the cytoplasm B. occurs before translation. C. requires RNA polymerase. D. requires a template DNA strand E. proceeds in the 5' to 3' direction of the growing mRNA molecule.
occurs on a ribosome in the cytoplasm
The antiparallel arrangement within double-stranded nucleic acid molecules refers to ... a. one strand is oriented towards one pole of the cell and the other strand is oriented towards the other pole b. a purine always bonding to a pyrimidine c. each base bonding at the 1' position of the sugar d. one strand is oriented in the 5' to 3' direction and the other strand is in the 3' to 5' direction
one strand is oriented in the 5' to 3' direction and the other strand is in the 3' to 5' direction
Membrane filtration can result in sterilization of serum and blood products by ... a. using high temperature moist heat. b. physically removing cells and viruses. c. removing protozoan cells via gravity. d. removing all toxins and other proteins.
physically removing cells and viruses.
The HIV protease and HCV protease inhibitors both work by ... A. preventing entry of the virus into the host cell B. blocking genome replication and transcription C. preventing the maturation of viral particles
preventing the maturation of viral particles
The nontranscribed region of DNA to which RNA polymerase binds to initiate transcription is called the ________. a. intron b. operator c. promoter d. operon e. exon
promoter
A gene is a transcription unit. It is marked at one end by a _______ and at the other end by a ________. a. Shine-Dalgarno sequence / poly-A tail b. start codon / stop codon c. promoter / terminator d. origin of replication / telomere
promoter / terminator
The process of using a cleansing technique with a chemical like a detergent to mechanically remove and reduce microorganisms on inanimate surfaces and debris to safe levels is ... a. antisepsis/degermation b. disinfection c. sterilization d. sanitization/decontamination
sanitization/decontamination
If pathogen A is more resistant to an erythromycin disc on a Kirby-Bauer plate compared to pathogen B, then pathogen A will have a(n) _____ zone of inhibition compared to pathogen B. A. smaller B. equal C. larger
smaller
Sterilization is achieved by ... A. flash pasteurization B. hot water C. boiling water D. steam autoclave E. All of the choices are correct.
steam autoclave
Which drugs target folic acid synthesis? (select all that apply) a. penicillins b. quinolones c. sulfonamides d. trimethoprim e. tetracyclines
sulfonamides trimethoprim
Broad-spectrum drugs that disrupt the body's normal resident microbiota often cause ... a. superinfections b. allergic reactions c. nephrotoxicity d. drug toxicity
superinfections
With transcription, the mRNA is identical in sequence to the ___________ of the DNA (except for the fact that T's in the DNA are replaced by U's in the RNA). A. template strand B. coding strand C. non-coding strand D. anti-sense strand
template strand
Fluoroquinolones, such as ciprofloxacin, are synthetic drugs that interfere with the action of DNA helicases. This means that ________. a. the bacterial cell will die since it cannot take in nutrients across the cell membrane b. the cell will die because it cannot make folic acid, which is a precursor to DNA and RNA, as well as amino acids c. binary fission cannot take place because the cell cannot translate proteins d. the bacterial cell will die since it cannot replicate or transcribe its DNA
the bacterial cell will die since it cannot replicate or transcribe its DNA
A clinical microbiologist sets up a tube dilution test to determine the MIC for a particular drug on a patient's isolated pathogen. What information will be gained from this test? a. whether or not the patient is allergic to this drug b. the smallest dose of drug that will yield toxic effects to the patient c.the smallest effective dose of drug that inhibits growth in vitro d. the growth rates of the bacterium at varying incubation temperatures
the smallest effective dose of drug that inhibits growth in vitro
The evolution of a virulent, toxin-producing bacterial strain due to a phage can occur in ... a. transduction b. conjugation c. transformation
transduction
The mechanism by which bacteria acquire genes by uptake of DNA released into the environment by a donor cell: a. conjugation b. transformation c. transduction d. budding
transformation
