Ch 25 Microbio Mastering HW Questions

A person who attended a picnic early in the day develops a very high fever and is unresponsive by the evening. This person most likely has been exposed to a(n) a. membrane disrupting toxin. b. superantigen. c. enterotoxin. d. cytotoxin.

b. superantigen.

Which of the following would be the first sign of an infection that resulted in the release of endotoxin? a. Weakness b. Fever c. Nausea d. Pain

b. Fever

Which of the following features of Salmonella prevent it from being phagocytosed? a. Flagella b. Invasins c. Fimbriae

a. Flagella

Which of the following enzymes breaks down the "glue" that holds cells together? a. Hyaluronidase b. Streptokinase c. Fibrinolysin d. Collagenase

a. Hyaluronidase

How does the protozoan Trypanosoma evade detection by the immune system? a. It can change the surface antigens frequently, preventing the immune system from tracking it. b. It can resist oxidation inside macrophages. c. It produces a capsule which is composed of polysaccharides similar to those found in the host. d. It prevents phagosome-lysosome fusion.

a. It can change the surface antigens frequently, preventing the immune system from tracking it.

Why is a release of endotoxin into the bloodstream potentially deadly? a. It can lower blood pressure and cause the patient to go into shock. b. It causes necrosis of the liver. c. Endotoxin can quickly enter the brain from the bloodstream, causing brain damage. d. It results in dehydration of the patient.

a. It can lower blood pressure and cause the patient to go into shock.

blank is an archaen found in dental plaque

Methanobrevibacter oralis

blank is the condition in which bacteria are reproducing in the blood and spreading.

Septicemia

blank is a common bacterial species found in dental plaque.

Streptococcus sobrinus

________ in saliva cleaves glycosidic linkages in the peptidoglycan that is present in bacterial cell walls, weakening the wall and potentially causing cell lysis. a. Lipid A b. Lysozyme c. Fibrin d. Mucus

b. Lysozyme

Pathogenicity is the ability 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.

All AB toxins have which of the following? a. immunogenic properties b. two subunits c. hemolytic activity d. lipid A

b. two subunits

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

d. protecting bacteria from host defense mechanisms.

Measles viruses are capable of inactivating host defenses by a. producing superantigens. b. destroying complement proteins. c. producing leukocidins. d. suppressing the immune system.

d. suppressing the immune system.

Certain traits that allow pathogens to create infection and cause disease are termed a. hyaluronidases. b. streptokinases. c. collagenases. d. virulence factors.

d. virulence factors.

The mouth can be an inhospitable environment with digestive enzymes in saliva and materials constantly moving through that can physically detach microbes. How does the dental plaque stay in place? choose all correct answers: -Tooth enamel contains a chemical to which bacteria can bind. -Saliva glycoproteins form a film to which bacteria can attach. -Bacteria may use dextran as an adhesive. -Bacteria may ferment lactic acid until they produce a sufficiently large crevice to allow a community to become established. -Bacteria may use capsule adhesins to adhere to glycoproteins.

-Saliva glycoproteins form a film to which bacteria can attach. -Bacteria may use dextran as an adhesive. -Bacteria may use capsule adhesins to adhere to glycoproteins. (Bacteria can attach to teeth using adhesins and dextran. Streptococcus sobrinus uses adhesins in its capsule that bind to glycoproteins that are deposited on teeth in saliva. Streptococcus mutans produces dextran, which is strongly adhesive.)

What steps are involved in the formation of dental plaque?

1. A thin film of glycoprotein is deposited on teeth by saliva 2. S. sobrinus uses capsule adhesins to attach to glycoproteins, and S. mutans uses dextran to attach to enamel within crevices. 3. Bacteria ferment glucose, producing lactic acid. 4. Dental caries form 5. Periodontal disease or other infections can develop.

blank is the condition in which bacteria are found in the blood.

Bacteremia

Compared with an endotoxin, would a bacterial exotoxin generally be more likely to function after it had been significantly heated? a. No, because exotoxins are heat-labile and less resistant to heating than endotoxins. b. No, because exotoxins are carbohydrates and endotoxins are proteins. c. Yes, because exotoxins are very heat stable compared to endotoxins. d. Yes, because exotoxins are proteins and non-living but endotoxins are part of the bacterial cell wall.

a. No, because exotoxins are heat-labile and less resistant to heating than endotoxins.

What is the etiologic agent of typhoid? a. Salmonella b. Shigella c. E. coli

a. Salmonella

How are superantigens different from other types of exotoxins? a. Superantigens cause an overstimulation of the host immune system. b. Superantigens only act against host neurons. c. Superantigens are comprised of two functional domains. d. Superantigens must be endocytosed into a target cell before becoming active.

a. Superantigens cause an overstimulation of the host immune system.

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? a. They are constructed of polymers that are synthesized in the cytoplasm and then transported out of the cell. b. They must provide a rigid structure that maintains an appropriate ratio of cell surface area to volume. 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 must block water and small molecules in order to regulate the exchange of matter and energy with their environment.

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

Endotoxins are also known as a. cytokines. b. Lipid A. c. interleukin-1. d. prostaglandins.

b. Lipid A.

When would endotoxins be released from a bacterial cell? a. When the cell dies b. During bacterial conjugation c. When the cell attaches to a host cell in the human body d. When the cell moves toward a energy source

a. When the cell dies

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

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

An exotoxin that has the ability to kill or damage host cells is referred to as a(n) a. cytotoxin. b. neurotoxin. c. superantigen. d. enterotoxin. e. A-B toxin.

a. cytotoxin.

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

a. fimbriated strains of Escherichia coli

Which of the following is a major growth-limiting micronutrient that influences microbial growth? a. iron b. sugar c. water d. vitamin K

a. iron

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

a. pathogenesis.

Pathogenicity and virulence differ in that a. 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. b. pathogenicity only refers to pathogens, whereas virulence refers to any microbe that can cause an infection. c. virulence only refers to pathogens, whereas pathogenicity refers to any microbe that can cause an infection. d. 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.

a. 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.

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

a. proteins / lipopolysaccharide-lipoprotein complexes

The spread of pathogens through the blood and lymph systems that results in a bloodborne systemic infection is called a. septicemia. b. cancer. c. pathogenesis. d. bacteremia.

a. septicemia.

Septicemia is an example of a a. systemic infection. b. transient infection. c. autoimmune infection. d. localized infection.

a. systemic infection.

Which domain of the A-B toxin binds to cell surface receptors on the host cell? a. A domain b. B domain c. Both the A and B domains have the ability to bind to cell surface receptors. d. A-B toxins do not bind to cell surfaces.

b. B domain

Where do Salmonella pathogens grow and replicate in the infected host? a. Inside Shigella cells b. Inside phagocytes c. Inside intestinal epithelial cells d. Inside M cells

b. Inside phagocytes

How does a capsule help certain bacteria evade detection by the immune system? a. Capsules allow the bacteria to stick together, creating a larger mass that is too big for immune cells to engulf. b. The capsule is composed of polysaccharides that are similar to those found in the host; thus, the immune system does not recognize it as foreign. c. The capsule makes the bacterium too sticky to be phagocytosed by the immune cells. d. Capsules have the ability to destroy antibodies secreted by the immune system.

b. The capsule is composed of polysaccharides that are similar to those found in the host; thus, the immune system does not recognize it as foreign.

How are immune cells able to detect foreign pathogens? a. They detect foreign, unfamiliar chemical substances released by the invading cells. b. They are able to detect structures on the surfaces of foreign cells that are not found in the host. c. They can compare the DNA sequences from the foreign cells to host DNA.

b. They are able to detect structures on the surfaces of foreign cells that are not found in the host.

How do fibrinolysins enhance a pathogen's virulence? a. They destroy the fibers that are found at the base of superficial tissues, allowing for deeper penetration by the pathogen. b. They break down fibrin proteins that are involved in clot formation, allowing the cells to penetrate deep into damaged skin. c. They destroy the molecules that hold cells together.

b. They break down fibrin proteins that are involved in clot formation, allowing the cells to penetrate deep into damaged skin.

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

b. capsule.

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? a. endotoxin b. collagenase, an enzyme that destroys collagen, which is a major protein of connective tissues c. nuclease, an enzyme that breaks down nucleic acids d. a neurotoxin

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

A pharmaceutical company that uses the Limulus amoebocyte lysate (LAL) assay to test water that is used to make sterile saline for intravenous administration is trying to detect small amounts of which of the following? a. Vibrio cholerae b. endotoxin c. amoebae d. E. coli

b. endotoxin (Vibrio cholerae are pathogens often found in water, but they are removed during sterilization of the water)

The diphtheria exotoxin is an A-B toxin that __________. a. causes host cell lysis b. is found only in Corynebacterium diphtheriae cells that have been infected with lysogenic bacteriophage β c. is found in all Corynebacterium diphtheriae cells d. is encoded for by genes in the chromosome of Corynebacterium diphtheriae cells

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

A patient who has been hospitalized with uncontrolled muscle spasms has probably been infected with bacteria that secrete a(n) a. enterotoxin. b. neurotoxin. c. membrane disrupting toxin. d. superantigen.

b. neurotoxin.

Dental plaque consists of a biofilm, with bacteria carefully arranged in a community. What are the advantages of forming a biofilm? a. Biofilms help to shift nutrients to the bacteria in the center. b. Biofilms produce an extracellular polymer that digests enamel. c. Biofilms provide protection from immune attack. d. Biofilms provide a way for bacteria to quickly move from the surface into the bloodstream.

c. Biofilms provide protection from immune attack.

How can capsules enable bacteria to evade the immune system? a. Capsules can bind up IgA, rendering it inactive. b. A capsule is a superantigen that distracts the immune system. c. Capsules block the complement biding sites on the surface of the pathogen.

c. Capsules block the complement biding sites on the surface of the pathogen.

Where is the site of Shigella attachment in the host? a. Intestinal epithelial cells b. Leukocytes c. M cells d. Phagocytes

c. M cells

What are leukocidins? a. Molecules that destroy the complement proteins b. Molecules that can degrade IgA c. Molecules that are capable of destroying phagocytes

c. Molecules that are capable of destroying phagocytes

Meningitis and gonorrhea are caused by a. Pseudomonas species. b. measles virus. c. Neisseria species.

c. Neisseria species.

Which of the following virulence factors would be found in Staphylococcus aureus? a. Hyaluronidase b. Streptokinase c. Staphylokinase d. Collagenase

c. Staphylokinase

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 __________. a. Sucrose and other purified sugars cause pitting of the tooth surfaces. b. Only purified sucrose and fructose can be fermented or produce acids in the oral cavity. c. Sucrose is required for the production of adhesive dextran by Streptococcus mutans. d. Lactobacilli require sucrose in order to form biofilms on tooth surfaces.

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

For several months a graduate student has been working with a pure culture of a suspected bacterial pathogen in an attempt to determine whether it causes disease in various animal models. She had initially found that the organism was highly virulent in mice, but when she attempted to replicate her early experiments weeks later, all of the new experimentally infected mice survived. The student has brought her surprising findings to the lab's weekly research meeting. What advice could you give her? a. The bacterial culture may have been contaminated. b. The mice may have become immune to the disease. c. The bacterial strain may have become attenuated. d. The bacterial culture may not have been viable.

c. The bacterial strain may have become attenuated. (Attenuation is the decrease or loss of virulence of a pathogen.)

How do Shigella cells move between host cells? a. They are secreted by phagocytes. b. They lyse the M cell, releasing thousands of new cells to infect other host cells. c. They can polymerize actin molecules from the epithelial cells into tail-like structures that propel them from one cell to another. d. They are secreted directly into the epithelial cells from the M cells.

c. They can polymerize actin molecules from the epithelial cells into tail-like structures that propel them from one cell to another.

How do superantigens enable pathogens to hide from the immune system if they actually stimulate the immune system? a. They cause the immune system to destroy IgA antibodies. b. They cause the immune system to turn on itself. c. They cause the immune system to produce an exaggerated response, distracting it from the actual pathogen. d. They cause fever, which destroys the complement proteins.

c. They cause the immune system to produce an exaggerated response, distracting it from the actual pathogen.

A pathogen must __________ in order for it to cause disease. a. attach b. secrete a toxin c. attach and multiply d. enter a host

c. attach and multiply

The process by which white blood cells ingest and kill bacteria is called a. transcription. b. exocytosis. c. phagocytosis. d. translation.

c. phagocytosis.

Although it had been thought that dental plaque consisted primarily of streptococci, more recent research showed that a variety of microbes are present. According to the chapter, what approaches were used to identify these additional microbes and to determine their three-dimensional structure in the biofilm? a. analysis of oxygen consumption b. metagenomic analysis alone c. phylogenetic probes/fluorescent in situ hybridization d. streak plates/spread plates/pour plates

c. phylogenetic probes/fluorescent in situ hybridization

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

c. superantigen toxins

Which of the following is considered an immunocompromised host? a. an 85-year-old cancer patient b. a heart-transplant patient c. a patient born without any B cells d. All of the listed responses are correct.

d. All of the listed responses are correct.

Endotoxins are comparatively different from exotoxins, because __________. a. endotoxins are not secreted proteins b. exotoxins can affect sites distant from the infection site c. endotoxins are associated with more fatalities d. All the listed responses are correct.

d. All the listed responses are correct.

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

d. Disease

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

d. Healthcare-associated infections

Which of the following is NOT a subunit of lipopolysaccharide (LPS)? a. core polysaccharide b. O-specific polysaccharide c. lipid A d. M protein

d. M protein

Which of the following is a reason that specific pathogens tend to infect specific tissues? a. Microbes preferentially target external tissues, such as skin, as the environment is more favorable for their growth than inside the body. b. Tissues with neutral pH are colonized but those with acidic or alkaline pH are not. c. Some tissues have receptors for microbes, but others do not. d. There are chemical and physical differences between tissues.

d. There are chemical and physical differences between tissues.

Which of the following microorganisms actually grows inside the macrophage? a. Shigella b. Leishmania c. Streptococcus pneumoniae d. Tuberculosis bacterium e. Legionella

d. Tuberculosis bacterium