Micro. Biology: Quiz 10 (Chapt. 25)

________ are toxic proteins released from the pathogen during normal growth. Select one: a.) Exotoxins b.) Endotoxins c.) Microtoxins d.) Macrotoxins

a.) Exotoxins

________ are microbial infections acquired by hospital patients with noninfectious diseases because they are compromised hosts. Select one: a.) Healthcare-associated infections b.) Virulent infections c.) Immunocompromised infections d.) Pathogenic infections

a.) Healthcare-associated infections

Pathogenicity islands are clusters of genes for virulence factors that are located together on the bacterial chromosome. Select one: a.) True b.) False

a.) True

________ is a damage or injury to a host organism that impairs its function. Select one: a.) Infection b.) Disease c.) Transmission d.) Trauma

b.) Diesease

Cytolytic toxins Select one: a.) are extracellular proteins. b.) are extracellular proteins that cause cell lysis and death by damaging the host cytoplasmic membrane. c.) damage host cytoplasmic membrane. d.) cause cell lysis and death.

b.) are extracellular proteins that cause cell lysis and death by damaging the host cytoplasmic membrane.

The condition that results when some bacteria are shed in the bloodstream and distributed to distant parts of the body but do not reproduce in the blood is called Select one: a.) septicemia. b.) bacteremia. c.) uremia. d.) erythemia.

b.) bacteremia.

Endotoxins are comparatively different from exotoxins, because __________.Hint 1. Endotoxins. Endotoxins are substances that are inside the cell and are released when the cell lyses. They can cause fever, vomiting, and diarrhea. Endotoxins rarely cause death. Select one: a.) endotoxins are associated with more fatalities b.) endotoxins are not secreted proteins c.) All the listed responses are correct. d.) exotoxins can affect sites distant from the infection site

c.) All the listed responses are correct.

Shiga toxin is an enterotoxin that is produced by Select one: a.) Escherichia coli O157: H7. b.) Vibrio cholerae. c.) Shigella dysenteriae. d.) Clostridium tetani.

c.) Shigella dysenteriae.

Virulence factors that enhance invasiveness of a pathogen can include __________. Hint 1. invasion, infection, and virulence factors.In order for a pathogen to cause tissue damage, the organism must be able to grow and multiply within the host. Next, the pathogen needs to be able to invade host tissues and cause damage. Select one: a.) collagenase b.) coagulase c.) exotoxins d.) All of the listed responses are correct.

d.) All of the listed responses are correct.

Which genus produces hyaluronidase? Select one: a.) Procholorococcus b.) Shigella c.) Mycobacterium d.) Streptococcus

d.) Streptococcus

Native peoples often experience an increase in the incidence of dental caries after they are introduced to imported processed foods. This finding could be explained by the fact that __________. Hint 1. [[Risk factors for infection]] Many factors can affect host susceptibility to infection, in addition to the virulence of the pathogen. Select one: a.) Lactobacilli require sucrose in order to form biofilms on tooth surfaces. b.) Only purified sucrose and fructose can be fermented or produce acids in the oral cavity. c.) Sucrose and other purified sugars cause pitting of the tooth surfaces. d.) Sucrose is required for the production of adhesive dextran by Streptococcus mutans.

d.) Sucrose is required for the production of adhesive dextran by Streptococcus mutans.

Which of the following is NOT important for the adherence of bacteria to host tissues? Select one: a.) capsule b.) slime layer c.) adhesins d.) lipopolysaccharides

d.) lipopolysaccharides

The best term to describe the general process by which microorganisms cause diseases is known as Select one: a.) virulence. b.) invasion. c.) infection. d.) pathogenesis.

d.) pathogenesis.

A patient admitted to the hospital with muscle weakness and paralysis is put on a ventilator because of breathing difficulties. It is determined that the symptoms are the result of a bacterial exotoxin. Which of the following is the most likely source of this toxin? Hint 1. [[Exotoxins]] Some exotoxins act as neurotoxins, affecting the actions of neurons and the muscles they control. Select one: a.) canned food b.) a puncture wound c.) contaminated water d.) airborne bacteria

a.) canned food

Which of the following is most likely to cause disease? Hint 1. pathogenicity and virulence. Virulence is the relative ability of a pathogen to cause disease in a host. The level of virulence combined with the amount of a pathogen are related to the likelihood of disease. Select one: a.) injection of 10^5 cells of a highly virulent bacterial species into a mouse b.) injection of 10^1 cells of a highly virulent bacterial species into a mouse c.) injection of 10^3 cells of a moderately virulent bacterial species into a mouse d.) injection of 10^6 cells of a low virulent bacterial species into a mouse

a.) injection of 10^5 cells of a highly virulent bacterial species into a mouse

Decalcification of the tooth enamel is caused by Select one: a.) lactic acid. b.) lipopolysaccharide. c.) dextrans. d.) formic acid.

a.) lactic acid.

Capsules are particularly important for Select one: a.) protecting bacteria from host defense mechanisms. b.) making bacteria less pathogenic. c.) allowing bacteria to become more phagocytic. d.) making bacteria more vulnerable to host defense mechanisms.

a.) protecting bacteria from host defense mechanisms.

The collective term for the organisms living on or in the human body, as opposed to a general term for organisms in an environmental habitat, is Select one: a.) the human microbiome. b.) the microbiota. c.) transient microbial flora. d.) pathogens.

a.) the human microbiome.

Clostridium perfringens causes gas gangrene, a serious infection of the muscle tissues that can lead to amputation. Clostridium are Gram-positive endospore-formers and obligate anaerobes that are killed when exposed to oxygen. Which of the following virulence factors would be most helpful to this organism in establishing an infection? Hint 1. In order to establish a successful infection, a pathogen must arrive at a susceptible site, adhere, invade, acquire nutrients, and grow. Select one: a.) endotoxin b.) collagenase, an enzyme that destroys collagen, which is a major protein of connective tissues c.) a neurotoxin d.) nuclease, an enzyme that breaks down nucleic acids

b.) collagenase, an enzyme that destroys collagen, which is a major protein of connective tissues

Tetanus toxin causes Select one: a.) hemolytic uremic syndrome. b.) muscles to be unable to relax. c.) severe diarrhea. d.) muscles to be unable to contract.

b.) muscles to be unable to relax.

Pathogenicity is the ability Select one: a.) of the host to resist damage by the pathogen. b.) of the pathogen to inflict damage on the host. c.) of the host to inflict damage on the pathogen. d.) None of these are correct.

b.) of the pathogen to inflict damage on the host.

Exotoxins are ________, but endotoxins are ________. Select one: a.) carbohydrates / proteins b.) proteins / lipopolysaccharide-lipoprotein complexes c.) lipids / proteins d.) lipopolysaccharide-lipoprotein complexes / proteins

b.) proteins / lipopolysaccharide-lipoprotein complexes

All AB toxins have which of the following? Hint 1. [[Exotoxins]] Specific exotoxins are produced by different species of bacteria and can cause very different effects on the host. Select one: a.) hemolytic activity b.) two subunits c.) immunogenic properties d.) lipid A

b.) two subunits

A researcher wanted to determine the LD50 (lethal dose that kills 50% of the infected hosts) for a newly isolated bacterial pathogen. Mice were inoculated with diluted cultures containing between 101 and 107 cells. After two days, all of the mice had died EXCEPT for the uninoculated controls. Which of the following is the most likely explanation? Hint 1. Pathogenesis. Pathogens can vary in virulence, resulting in different infectious doses and different levels of morbidity and mortality in various hosts. Select one: a.) Mice are not good model animals for this pathogen. b.) The pathogen has become attenuated. c.) This pathogen is highly virulent in mice. d.) The pathogen has a very high LD50.

c.) This pathogen is highly virulent in mice.

An outer coat consisting of a dense, well-defined polymer layer surrounding a cell and used in attachment is called a Select one: a.) pilus. b.) cytoplasmic membrane. c.) capsule. d.) lipopolysaccharide layer.

c.) capsule.

Factors that enhance an organism's ability to adhere to host tissues include __________. Hint 1. Adherence. In order to cause an infection or initiate a biofilm, bacteria must be able to attach to surfaces. Some of these factors are covalently attached to bacteria, and others are noncovalently attached. Select one: a.) adherence enzymes b.) peptidoglycan c.) fimbriae d.) lipopolysaccharide

c.) fimbriae

Which of the following is more likely to cause urinary tract infections? Select one: a.) non-fimbriated strains of Escherichia coli b.) None of the answers are correct. c.) fimbriated strains of Escherichia coli d.) both fimbriated and non-fimbriated strains of Escherichia coli

c.) fimbriated strains of Escherichia coli

Which of the following is a way to prevent attenuation and maintain virulence in a bacterium? Select one: a.) antibiotic therapy b.) laboratory subculture c.) inoculating an animal with the bacterium d.) polymerase chain reaction (PCR)

c.) inoculating an animal with the bacterium

The diphtheria exotoxin is an A-B toxin that __________. Hint 1. [[exotoxins]] A-B exotoxins contain two protein subunits. The B subunit binds to the cell surface and allows the A subunit to cross the plasma membrane and cause damage inside the host cell. Select one: a.) is found in all Corynebacterium diphtheriae cells b.) causes host cell lysis c.) is found only in Corynebacterium diphtheriae cells that have been infected with lysogenic bacteriophage β d.) is encoded for by genes in the chromosome of Corynebacterium diphtheriae cells

c.) is found only in Corynebacterium diphtheriae cells that have been infected with lysogenic bacteriophage β

Pathogenicity and virulence differ in that Select one: a.) pathogenicity only refers to pathogens, whereas virulence refers to any microbe that can cause an infection. b.) virulence refers to the overall ability of a microbe to cause disease, whereas pathogenicity refers to the ability of one microbe to cause disease relative to another. c.) pathogenicity refers to the overall ability of a microbe to cause disease, whereas virulence refers to the ability of one microbe to cause disease relative to another. d.) virulence only refers to pathogens, whereas pathogenicity refers to any microbe that can cause an infection.

c.) pathogenicity refers to the overall ability of a microbe to cause disease, whereas virulence refers to the ability of one microbe to cause disease relative to another.

Staphylococcus aureus and Streptococcus pyogenes strains can produce ________ that cause the severe and sometimes life-threatening symptoms of toxic shock syndrome. Select one: a.) endotoxin b.) AB toxins c.) superantigen toxins d.) cytolytic

c.) superantigen toxins

Salmonella species use ________ to facilitate attachment to gastrointestinal tissue. Select one: a.) antiphagocytic proteins b.) pili c.) type I fimbriae d.) siderophores

c.) type I fimbriae

A patient is brought to the hospital with severe gastrointestinal distress, including cramps, dehydration and diarrhea. Which of the following symptoms would indicate that the pathogen is Vibrio cholerae? Hint 1. Intestinal distress caused by infectious bacteria usually results from the action of one or more enterotoxins. Many enterotoxins are AB toxins and can be proteases, cytolytic toxins, superantigens, or can affect regulatory systems. Select one: a.) frequent vomiting b.) occasional diarrhea but no blood in the stool c.) bloody, foul smelling diarrhea d.) voluminous watery diarrhea

d.) voluminous watery diarrhea

The cell walls of bacteria, fungi, and plant cells and the extracellular matrix of animal cells are all external to the plasma membrane. Which of the following is a characteristic common to all of these extracellular structures? Select one: a.) They must provide a rigid structure that maintains an appropriate ratio of cell surface area to volume. b.) They must block water and small molecules in order to regulate the exchange of matter and energy with their environment. c.) They are composed of a mixture of lipids and carbohydrates. d.) They must permit information transfer between the cell's cytoplasm and the nucleus. e.) They are constructed of polymers that are synthesized in the cytoplasm and then transported out of the cell.

e.) They are constructed of polymers that are synthesized in the cytoplasm and then transported out of the cell.