MicroBiology: End of Chapter Questions for Exam #3

The component(s) of a virus that is/are extended from the envelope for attachment is/are the:


1. capsomeres
2. spikes
3. nucleic acid
4. viral whiskers

spikes

Which of the following does a virus lack? Select all that apply.


1. ribosomes
2. metabolic processes
3. nucleic acid
4. glycoprotein

ribosomes

metabolic processes

The envelope of a virus is derived from the host’s


1. nucleic acids
2. membrane structures
3. cytoplasm
4. genome

membrane structures

In naming viruses, the family name ends with ________ and genus name ends with _________.


1. −virus; −viridae
2. -virion; -virus
3. −virion; virus
4. −virus; virion

\-virion; -virus

What is another name for a nonenveloped virus?


1. enveloped virus
2. provirus
3. naked virus
4. latent virus

naked virus

Which of the following leads to the destruction of the host cells?


1. lysogenic cycle
2. lytic cycle
3. prophage
4. temperate phage

lytic cycle

A virus obtains its envelope during which of the following phases?

a. attachment

b. penetration

c. assembly

d. release

d. release

Which of the following components is brought into a cell by HIV?

a. a DNA-dependent DNA polymerase

b. RNA polymerase

c. ribosome

d. reverse transcriptase

d. reverse transcriptase

A positive-strand RNA virus:

a. must first be converted to a mRNA before it can be translated.

b. can be used directly to translate viral proteins.

c. will be degraded by host enzymes.

d. is not recognized by host ribosomes.

b. can be used directly to translate viral proteins.

What is the name for the transfer of genetic information from one bacterium to another bacterium by a phage?

a. transduction

b. penetration

c. excision

d. translation

a. transduction

Which of the followings cannot be used to culture viruses?


1. tissue culture
2. liquid medium only
3. embryo
4. animal host

liquid medium only

Which of the following tests can be used to detect the presence of a specific virus?


1. EIA
2. RT-PCR
3. PCR
4. all of the above

all of the above

Which of the following is NOT a cytopathic effect?


1. transformation
2. cell fusion
3. mononucleated cell
4. inclusion bodies

mononucleated cell

Which of these infectious agents do not have nucleic acid?

a. viroids

b. viruses

c. bacteria

d. prions

d. prions

Which of the following is true of prions?


1. They can be inactivated by boiling at 100 °C.
2. They contain a capsid.
3. They are a rogue form of protein, PrP.
4. They can be reliably inactivated by an autoclave.

They are a rogue form of protein, PrP.

A virus that infects a bacterium is called a/an ___________________.

Bacteriophage

A/an __________ virus possesses characteristics of both a polyhedral and helical virus.

complex

A virus containing only nucleic acid and a capsid is called a/an ___________________ virus or __________________ virus.

naked or nonenveloped

The ____________ _____________ on the bacteriophage allow for binding to the bacterial cell

tail fibers

An enzyme from HIV that can make a copy of DNA from RNA is called _______________________.

reverse transcriptase

For lytic viruses, _________________ is a phase during a viral growth curve when the virus is not detected

eclipse

Viruses can be diagnosed and observed using a(n) _____________ microscope

electron

Cell abnormalities resulting from a viral infection are called ____________ _____________.

cytopathic effects

Both viroids and virusoids have a(n) _________ genome, but virusoids require a(n) _________ to reproduce.

RNA, helper virus

Which of the following types of medical items requires sterilization?


1. needles
2. bed linens
3. respiratory masks
4. blood pressure cuffs

needles

Which of the following is suitable for use on tissues for microbial control to prevent infection?

a. disinfectant

b. antiseptic

c. sterilant

d. water

b. antiseptic

Which biosafety level is appropriate for research with microbes or infectious agents that pose moderate risk to laboratory workers and the community, and are typically indigenous?

a. BSL-1

b. BSL-2

c. BSL-3

d. BSL-4

b. BSL-2

Which of the following best describes a microbial control protocol that inhibits the growth of molds and yeast?

a. bacteriostatic

b. fungicidal

c. bactericidal

d. fungistatic

d. fungistatic

The decimal reduction time refers to the amount of time it takes to which of the following?


1. reduce a microbial population by 10%
2. reduce a microbial population by 0.1%
3. reduce a microbial population by 90%
4. completely eliminate a microbial population

reduce a microbial population by 90%

Which of the following methods brings about cell lysis due to cavitation induced by rapid localized pressure changes?


1. microwaving
2. gamma irradiation
3. ultraviolet radiation
4. sonication

sonication

Which of the following terms is used to describe the time required to kill all of the microbes within a sample at a given temperature?


1. D-value
2. thermal death point
3. thermal death time
4. decimal reduction time

thermal death time

Which of the following microbial control methods does not actually kill microbes or inhibit their growth but instead removes them physically from samples?


1. filtration
2. desiccation
3. lyophilization
4. nonionizing radiation

filtration

Which of the following refers to a disinfecting chemical dissolved in alcohol?

a. iodophor

b. tincture

c. phenolic

d. peroxygen

b. tincture

Which of the following peroxygens is widely used as a household disinfectant, is inexpensive, and breaks down into water and oxygen gas?


1. hydrogen peroxide
2. peracetic acid
3. benzoyl peroxide
4. ozone

hydrogen peroxide

Which of the following chemical food preservatives is used in the wine industry but may cause asthmatic reactions in some individuals?


1. nitrites
2. sulfites
3. propionic acid
4. benzoic acid

sulfites

Bleach is an example of which group of chemicals used for disinfection?


1. heavy metals
2. halogens
3. quats
4. bisbiguanides

halogens

Which chemical disinfectant works by methylating enzymes and nucleic acids and is known for being toxic and carcinogenic?


1. sorbic acid
2. triclosan
3. formaldehyde
4. hexaclorophene

formaldehyde

Which type of test is used to determine whether disinfectant solutions actively used in a clinical setting are being used correctly?


1. disk-diffusion assay
2. phenol coefficient test
3. in-use test
4. use-dilution test

in-use test

The effectiveness of chemical disinfectants has historically been compared to that of which of the following?


1. phenol
2. ethyl alcohol
3. bleach
4. formaldehyde

phenol

Which of the following refers to a germicide that can kill vegetative cells and certain enveloped viruses but not endospores?


1. high-level germicide
2. intermediate-level germicide
3. low-level germicide
4. sterilant

low-level germicide

Sanitization leaves an object free of microbes.

TRUE

FALSE

FALSE

Ionizing radiation can penetrate surfaces, but nonionizing radiation cannot.

TRUE

FALSE

TRUE

Moist-heat sterilization protocols require the use of higher temperatures for longer periods of time than do dry-heat sterilization protocols do.

TRUE

FALSE

FALSE

Soaps are classified as disinfectants.

TRUE

FALSE

FALSE

Mercury-based compounds have fallen out of favor for use as preservatives and antiseptics.

TRUE

FALSE

TRUE

A medical item that comes into contact with intact skin and does not penetrate sterile tissues or come into contact with mucous membranes is called a(n) ________ item.

noncritical

The goal of ________ ________ protocols is to rid canned produce of Clostridium botulinum endospores.

commercial sterilization

In an autoclave, the application of pressure to ________ is increased to allow the steam to achieve temperatures above the boiling point of water

steam

Doorknobs and other surfaces in clinical settings are often coated with ________, ________, or ________ to prevent the transmission of microbes.

copper, nickel, zinc

If a chemical disinfectant is more effective than phenol, then its phenol coefficient would be ________ than 1.0

greater

If used for extended periods of time, ________ germicides may lead to sterility.

high-level

In the disk-diffusion assay, a large zone of inhibition around a disk to which a chemical disinfectant has been applied indicates ________ of the test microbe to the chemical disinfectant.

susceptibility or sensitivity

A scientist discovers that a soil bacterium he has been studying produces an antimicrobial that kills gram- negative bacteria. She isolates and purifies the antimicrobial compound, then chemically converts a chemical side chain to a hydroxyl group. When she tests the antimicrobial properties of this new version, she finds that this antimicrobial drug can now also kill gram-positive bacteria. The new antimicrobial drug with broad-spectrum activity is considered to be which of the following?

a. resistant

b. semisynthetic

c. synthetic

d. natural

semisynthetic

Which of the following antimicrobial drugs is synthetic?

a. sulfanilamide

b. penicillin

c. actinomycin

d. neomycin

a. sulfanilamide

Which of the following combinations would most likely contribute to the development of a superinfection?


1. long-term use of narrow-spectrum antimicrobials
2. long-term use of broad-spectrum antimicrobials
3. short-term use of narrow-spectrum

antimicrobials
4. short-term use of broad-spectrum antimicrobials

long-term use of broad-spectrum antimicrobials

Which of the following routes of administration would be appropriate and convenient for home administration of an antimicrobial to treat a systemic infection?

a. oral

b. intravenous

c. topical

d. parenteral

oral

Which clinical situation would be appropriate for treatment with a narrow-spectrum antimicrobial drug?


1. treatment of a polymicrobic mixed infection in the intestine
2. prophylaxis against infection after a surgical procedure
3. treatment of strep throat caused by culture identified Streptococcus pyogenes
4. empiric therapy of pneumonia while waiting for culture results

treatment of strep throat caused by culture identified Streptococcus pyogenes

Which of the following terms refers to the ability of an antimicrobial drug to harm the target microbe without harming the host?


1. mode of action
2. therapeutic level
3. spectrum of activity
4. selective toxicity

selective toxicity

Which of the following is not a type of β-lactam antimicrobial?

a. penicillins

b. glycopeptides

c. cephalosporins

d. monobactams

b. glycopeptides

Which of the following does not bind to the 50S ribosomal subunit?

a. tetracyclines

b. lincosamides

c. macrolides

d. chloramphenicol

a. tetracyclines

Which of the following antimicrobials inhibits the activity of DNA gyrase?


1. polymyxin B
2. clindamycin
3. nalidixic acid
4. rifampin

nalidixic acid

Which of the following is not an appropriate target for antifungal drugs?


1. ergosterol
2. chitin
3. cholesterol
4. β(1→3) glucan

cholesterol

Which of the following drug classes specifically inhibits neuronal transmission in helminths?


1. quinolines
2. avermectins
3. amantadines
4. imidazoles

avermectins

Which of the following is a nucleoside analog commonly used as a reverse transcriptase inhibitor in the treatment of HIV?


1. acyclovir
2. ribavirin
3. adenine-arabinoside
4. azidothymidine

azidothymidine

Which of the following is an antimalarial drug that is thought to increase ROS levels in target cells?


1. artemisinin
2. amphotericin b
3. praziquantel
4. pleconaril

artemisinin

Which of the following resistance mechanisms describes the function of β-lactamase?


1. efflux pump
2. target mimicry
3. drug inactivation
4. target overproduction

drug inactivation

Which of the following resistance mechanisms is commonly effective against a wide range of antimicrobials in multiple classes?


1. efflux pump
2. target mimicry
3. target modification
4. target overproduction

efflux pump

Which of the following resistance mechanisms is the most nonspecific to a particular class of antimicrobials?


1. drug modification
2. target mimicry
3. target modification
4. efflux pump

efflux pump

Which of the following types of drug-resistant bacteria do not typically persist in individuals as a member of their intestinal microbiota?


1. MRSA
2. VRE
3. CRE
4. ESBL-producing bacteria

MRSA

In the Kirby-Bauer disk diffusion test, the _______ of the zone of inhibition is measured and used for interpretation.


1. diameter
2. microbial population
3. circumference
4. depth

diameter

Which of the following techniques cannot be used to determine the minimum inhibitory concentration of an antimicrobial drug against a particular microbe?

a. Etest

b. microbroth dilution test

c. Kirby-Bauer disk diffusion test

d. macrobroth dilution test

Kirby-Bauer disk diffusion test

The utility of an antibiogram is that it shows antimicrobial susceptibility trends

a. over a large geographic area.

b. for an individual patient.

c. in research laboratory strains.

d. in a localized population.

in a localized population.

Which of the following has yielded compounds with the most antimicrobial activity?

a. water

b. air

c. volcanoes

d. soil

soil

Narrow-spectrum antimicrobials are commonly used for prophylaxis following surgery.

TRUE

FALSE

FALSE

β-lactamases can degrade vancomycin.

TRUE

FALSE

FALSE

Echinocandins, known as “penicillin for fungi,” target β(1→3) glucan in fungal cell walls.

TRUE

FALSE

TRUE

If drug A produces a larger zone of inhibition than drug B on the Kirby-Bauer disk diffusion test, drug A should always be prescribed

TRUE

FALSE

FALSE

The rate of discovery of antimicrobial drugs has decreased significantly in recent decades.

TRUE

FALSE

TRUE

The group of soil bacteria known for their ability to produce a wide variety of antimicrobials is called the ________.

actinomycetes

The bacterium known for causing pseudomembranous colitis, a potentially deadly superinfection, is ________.

*Clostridium difficile*

Selective toxicity antimicrobials are easier to develop against bacteria because they are ________ cells, whereas human cells are eukaryotic.

prokaryotic

Antiviral drugs, like Tamiflu and Relenza, that are effective against the influenza virus by preventing viral escape from host cells are called ________.

neuraminidase inhibitors

Staphylococcus aureus, including MRSA strains, may commonly be carried as a normal member of the ________ microbiota in some people.

nasal

The method that can determine the MICs of multiple antimicrobial drugs against a microbial strain using a single agar plate is called the ________.

Etest

Which of the following would be a sign of an infection?


1. muscle aches
2. headache
3. fever
4. nausea

fever

Which of the following is an example of a noncommunicable infectious disease?


1. infection with a respiratory virus
2. food poisoning due to a preformed bacterial

toxin in food
3. skin infection acquired from a dog bite
4. infection acquired from the stick of a

contaminated needle

food poisoning due to a preformed bacterial toxin in food

During an oral surgery, the surgeon nicked the patient’s gum with a sharp instrument. This allowed Streptococcus, a bacterium normally present in the mouth, to gain access to the blood. As a result, the patient developed bacterial endocarditis (an infection of the heart). Which type of disease is this?

a. iatrogenic

b. nosocomial

c. vectors

d. zoonotic

a. iatrogenic

Which period is the stage of disease during which the patient begins to present general signs and symptoms?

a. convalescence

b. incubation

c. illness

d. prodromal

d. prodromal

A communicable disease that can be easily transmitted from person to person is which type of disease?


1. contagious
2. iatrogenic
3. acute
4. nosocomial

contagious

Which of the following is a pathogen that could not be identified by the original Koch’s postulates?


1. Staphylococcus aureus
2. Pseudomonas aeruginosa
3. Human immunodeficiency virus
4. Salmonella enterica serovar Typhimurium

Human immunodeficiency virus

Pathogen A has an ID50 of 50 particles, pathogen B has an ID50 of 1,000 particles, and pathogen C has an ID50 of 1 × 106 particles. Which pathogen is most virulent?


1. pathogen A
2. pathogen B
3. pathogen C

pathogen A

Which of the following choices lists the steps of pathogenesis in the correct order?


1. invasion, infection, adhesion, exposure
2. adhesion, exposure, infection, invasion
3. exposure, adhesion, invasion, infection
4. disease, infection, exposure, invasion

exposure, adhesion, invasion, infection

Which of the following would be a virulence factor of a pathogen?


1. a surface protein allowing the pathogen to bind to host cells
2. a secondary host the pathogen can infect
3. a surface protein the host immune system

recognizes
4. the ability to form a provirus

a surface protein allowing the pathogen to bind to host cells

You have recently identified a new toxin. It is produced by a gram-negative bacterium. It is composed mostly of protein, has high toxicity, and is not heat stable. You also discover that it targets liver cells. Based on these characteristics, how would you classify this toxin?

a. superantigen

b. endotoxin

c. exotoxin

d. leukocidin

exotoxin

Which of the following applies to hyaluronidase?


1. It acts as a spreading factor.
2. It promotes blood clotting.
3. It is an example of an adhesin.
4. It is produced by immune cells to target pathogens.

It acts as a spreading factor.

Phospholipases are enzymes that do which of the following?

a. degrade antibodies

b. promote pathogen spread through connective tissue.

c. degrade nucleic acid to promote spread of pathogen

d. degrade cell membranes to allow pathogens to escape phagosomes

d. degrade cell membranes to allow pathogens to escape phagosomes

Which of the following is a major virulence factor for the fungal pathogen Cryptococcus?


1. hemolysin
2. capsule
3. collagenase
4. fimbriae

capsule

Which of the following pathogens undergoes antigenic variation to avoid immune defenses?

a. Candidab. 

b. Cryptococcus 

c. Plasmodium 

d. Giardia

Plasmodium

A difference between an acute disease and chronic __________.

illness

A person steps on a rusty nail and develops tetanus. In this case, the person has acquired a(n) __________ disease.

noncommunicable