Combo with CH 15: Microbial Mechanisms of Pathogenicity

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Which protein secreted by bacteria can take away iron from the host?

A) siderophores
B) M protein

siderophores.

Siderophores are bacterial iron-binding proteins that can take iron from the host iron-transport proteins.

Which substance can digest materials between host cells?

A) superantigens
B) hyaluronidase

hyaluronidase.

Hyaluronidase digests the material that holds together certain cells of the body.

Which type of toxin is able to induce chills, fever, weakness, and generalized aches?

A) endotoxin
B) exotoxin

endotoxin.

Endotoxins are the lipid A portion of LPS and induce chills, fever, weakness, and generalized aches.

Which of the following can impair phagocytosis by the host immune cells?

A) coagulase
B) M protein

M protein.

M protein, found on the cell surface and fimbriae of some bacteria, helps the bacteria resist phagocytosis.

Which molecule on the pathogen binds to the host cell?

A) the receptor
B) the adhesin

the adhesin.

Adhesins on bacteria bind specifically to receptors on the cells of the host.

Chemicals that digest blood clots are

A) lipopolysaccharides
B) kinases

kinases.

Kinases are bacterial enzymes that break down blood clots

Which disease is associated with Claviceps purpurea?

A) paralytic shellfish poisoning
B) ergotism

ergotism.

The ergot toxin produced by this fungus can cause hallucinations or gangrene in the extremities

An injection would be an example of which portal of entry?

A) the parenteral route
B) mucous membrane

the parenteral route.

This is a portal of entry for pathogens deposited directly into tissues beneath the skin and mucous membranes.

Which toxin would target the gastrointestinal tract?

A) a neurotoxin
B) an enterotoxin

an enterotoxin.

Enterotoxins are exotoxins that attack the lining of the gastrointestinal tract.

The ability to cause disease by overcoming the defenses of a host is known as

A) virulence
B) pathogenicity

WHY?

pathogenicity.

Pathogenicity is the ability to cause disease by overcoming the defenses of a host while virulence is the degree of pathogenicity of a microorganism.

True or False

Biofilms are particularly sensitive to disinfectants and antibiotics.

False

True or False

A hemolysin is involved in attachment between the pathogen and the host cell.

False

True or False

Saxitoxin is a neurotoxin produced by some genera of dinoflagellates

True

True or false

Superantigens are found on fimbriae and mediate attachment of the bacterium to host cells

false

Which of the following is an example of the parenteral portal of entry for microorganisms?

A) surgery
B) a hair follicle

surgery

Most exotoxins are of which type?

A) membrane-disrupting
B) A-B toxins

A-B toxins

Where are endotoxins usually found in a bacterial cell?

A) in the bacterial cell wall
B) in the cytoplasm

in the bacterial cell wall

Which of the following is a portal of entry for microbes?

A) the meninges
B) the respiratory tract

the respiratory tract.

Which of the toxin types is a protein?

A) endotoxin
B) exotoxin

exotoxin

Which of the toxins stimulates T cells to secrete cytokines?

A) membrane-disrupting toxins
B) superantigens

superantigens

What is the general term for observable changes in cells that occur as a result of viral infection?

A. transformation bodies
B. inclusion bodies
C. cytopathic effects
D. syncytium

cytopathic effects

Which of the following is a possible location for a bacterial adhesin?

A. pili
B. fimbriae
C. flagella
D. all of the these

all of the these

Which of the following virulence factors is specifically involved in helping an organism to physically spread throughout the body?

A. hemolysin
B. endotoxins
C. siderophores
D. hyaluronidase

hyaluronidase

Hyaluronidase breaks down hyaluronic acid, which is a sugar molecule that holds certain cells in the body together

Which of the following is an accurate statement about A-B toxins?

A. The A component binds to a receptor on the host cell.
B. The A and B components must remain attached in order to exert their effects on the cell.
C. They are proteins.
D. They are a type of endotoxin

They are proteins

B component that binds to the receptor. The A component alters the function of the cell, often by disrupting protein synthesis

Which of these organisms does NOT produce an enterotoxin?

A. Staphylococcus aureus
B. Vibrio cholerae
C. Shigella spp.
D. Clostridium botulinum

Clostridium botulinum

In some cases, viral infections may __________.

A. cause cells to produce endotoxin
B. cause cells to form capsules
C. cause cells to produce invasive enzymes such as hyaluronidase and collagenase
D. cause cells to lose contact inhibition

cause cells to lose contact inhibition

Which one of these bacterial proteins can take iron from human lactoferrin?

A. siderophore
B. protease
C. kinase
D. hyaluronidase

siderophore

Which of the following toxins is NOT produced by a bacterium as a result of lysogenic conversion?

A. endotoxin
B. botulinum neurotoxin
C. staphylococcal enterotoxin
D. diphtheria toxin

endotoxin

Which of these is a cell wall component that contributes to invasiveness?

A. endotoxin
B. coagulase
C. M protein
D. hemolysin

M protein

The M protein is a cell wall component of Streptococcus pyogenes. It helps the bacteria to adhere to host cells and resist phagocytosis

Which of these diseases CANNOT be prevented by toxoids?

A. tetanus
B. gram-negative septic shock
C. botulism
D. diphtheria

gram-negative septic shock

Which one of these substances would NOT be produced at the same time as coagulase?

A. capsules
B. fibrinolysin
C. hemolysin
D. fimbriae

fibrinolysin

Fibrinolysin dissolves fibrin clots

Which of these statements is true regarding portals of exit?

A. The portal of exit for tuberculosis is the skin.
B. Polioviruses most often use the respiratory portal of exit.
C. In most cases, a microbe uses the same portal for both entry and exit.
D. The urinary tract is the most common portal of exit.

In most cases, a microbe uses the same portal for both entry and exit.

Which one of these is NOT an example of pathogen entry via the parenteral route?

A. infection of a hair follicle
B. entry through a break in the skin caused by a cut
C. injection of the pathogen via a contaminated needle
D. injection via the bite of an infected insect

infection of a hair follicle

The symptoms of protozoan diseases are usually due to __________.

A. metabolic waste products
B. endotoxins
C. exotoxins
D. capsules

metabolic waste products

Which type of organism produces the toxin responsible for paralytic shellfish poisoning?

A. a protozoan
B. a helminth
C. an alga
D. a bacterium

an alga

All of the following are examples of cytopathic effects of viruses except ________.

1. cell surface antigens change
2. host cells fuse to form multinucleated syncytia
3. inclusion bodies are found in the cytoplasm or nucleus
4. None of these choices. There are no exceptions here.

4. None of these choices. There are no exceptions here.

Which of these effects is most likely to occur if a pathogen enters the body by a portal of entry other than the preferred one?
1. A more severe disease will result.
2. A milder disease will result.
3. A different disease of the same severity will result.
4. Pathogens cannot enter by alternate routes.

2. A milder disease will result

Which one of the following virulence factors contributes most to the spread of disease in the body?
1. hyaluronidase
2. hemolysin
3. endotoxin production
4. siderophore production

Hyaluronidase

The presence of endotoxins in a sterile fluid indicates ________.
1. gram-positive bacteria are growing
2. gram-negative bacteria are growing
3. the fluid is not sterile
4. the presence of gram-negative cell walls

The presence of gram-negative cell walls

Viruses can evade host defenses by ________.
1. producing enzymes that destroy antibody molecules
2. "hiding" inside host cells where they cannot be detected by the host's immune system
3. producing leukocidins that actively destroy white blood cells
4. inhibiting phagocytosis due to the presence of the viral envelope

2. "hiding" inside host cells where they cannot be detected by the host's immune system

Host cells transformed by viral infection may ________.

Lose contact inhibition

Which one of these bacterial proteins can take iron from human lactoferrin?
1. protease
2. siderophore
3. hyaluronidase
4. kinase

siderophore

Based on these LD50 values, which microbe is the most virulent? Assume each bacterium enters through the appropriate portal of entry.
1. Cryptosporidium-50 cells
2. Shigella-10 cells
3. E. coli O157-1000 cells
4. Vibrio cholerae-108 cells

Shigella 10 cells

Which of these is a cell wall component that contributes to invasiveness?
1. endotoxin
2. hemolysin
3. M protein
4. coagulase

M protein

Which of these diseases cannot be prevented by toxoids?
1. botulism
2. tetanus
3. gram-negative septic shock
4. diphtheria

Gram negative septic shock

Which one of these substances should not be produced at the same time as coagulase?
1. fibrinolysin
2. fimbriae
3. capsules
4. hemolysin

fibrinolysin

Which of these statements is true regarding portals of exit?

1. In most cases, a microbe uses the same portal for both entry and exit.
2. The urinary tract is the most common portal of exit.
3. The portal of exit for chicken pox, measles, and smallpox is the skin.
4. Polioviruses most often use the respiratory portal of exit.

In most cases, a microbe uses the same portal for both entry and exit

Which one of these is not an example of the parenteral route?
1. insect bite
2. cut
3. injection
4. hair follicle

Hair follicle

The symptoms of protozoan diseases are usually due to ________.

Metabolic waste products

Hepatitis B virus transmitted by a finger-stick device is transmitted by which portal of entry?

Parentral

Which of these substances does not protect a bacterium from phagocytosis?
1. leukocidins
2. siderophores
3. capsule
4. M protein

Siderophores

Symptoms of helminthic diseases are usually due to ________.

The presence of the parasite

The dose of microbes required to produce a measurable infection in half of the animals tested is referred to by the abbreviated term __________.

ID- 50

Infections acquired by bites, cuts, wounds, punctures, or surgery occur via the __________ route.

Parenteral

__________ are bacterial enzymes that lyse erythrocytes.

hemolysins

Fibrin clots can be dissolved by enzymes called _________.

Kinase

The scum that builds up on shower doors, the formation of dental plaque on teeth, and the algae growth on the walls of swimming pools are all examples of _______.

biofilms

_____ are toxins modified to retain their ability to induce antibody formation but lose their toxicity.

Toxoids

Toxins that stimulate proliferation of T cells non-specifically and provoke intense immune responses are called _________.

Superantigens

_______ are molecules on bacterial cell surfaces that enable them to adhere to the surface of host cells.

Adhesins

The release of endotoxins as bacteria are destroyed by phagocytes causes the phagocytes to release tumor necrosis factor (TNF) the life-threatening loss of blood pressure occuring due to the action of TNF is called __________.

Endotoxic shock

Lysogenic bacterial cells may express prophage DNA causing them to take on different characteristics in a process referred to as _______________.

Lysogenic conversion

Microbes are more likely to enter the body through the skin than through the mucous membranes. T/F

False

Although some pathogens cause disease after entering the body via food and water consumption, many such microbes are killed by chemicals involved in the digestive process. T/F

True

The same disease symptoms result, regardless of how a particular microbe enters the body. T/F

False

If bacteria A and B have LD50 values of 109 and 1010, respectively, more cells of A than B will be needed to kill the host. T/F

False

If bacteria attach to host tissue, they will cause disease. T/F

False

Adhesin molecules can vary in structure among strains of a given bacterial species. T/F

True

The glycocalyx (capsule/slime layer) can affect bacterial virulence by allowing attachment and by hindering phagocytosis. T/F

True

Most host damage resulting from bacterial infection is the result of direct damage by the microbe. T/F

False

Patient symptoms may worsen after antibiotic treatment of infections caused by gram-negative bacteria due to the sudden release of endotoxins. T/F

True

Accumulations of viral proteins and nucleic acids inside infected host cells are called inclusion bodies. T/F

True

If a patient has a deep tissue infection as the result of an animal bite on the arm, the portal of entry is described as the ________.

Parenteral route

Which would be the most unlikely location to find adhesin molecules on a newly discovered bacterium?

1. glycocalyx
2. fimbriae
3. capsule
4. ribosomes
5. cell wall

ribosomes

Which of these conditions would not affect the ability of Streptococcus mutans to attach to teeth?

1. the lack of a glycocalyx
2. the lack of the enzyme glucosyltransferase
3. the absence of Actinomyces, a bacterium that can be part of dental plaque
4. the inability to form dextran
5. the lack of sucrose

3. the absence of Actinomyces, a bacterium that can be part of dental plaque

Which of these statements is not true for bacterial capsules?

1. For Streptococcus pneumoniae, the encapsulated strain is more virulent.
2. Pathogenic and nonpathogenic bacteria can produce capsules.
3. Antibodies produced against a capsule cannot affect whether disease will occur.
4. The importance of the capsule to virulence for Streptococcus pneumoniae can be determined because there are strains both with and without the capsule.
5. Capsules related to virulence are produced by the causative agents of anthrax and bubonic plague.

3. Antibodies produced against a capsule cannot affect whether disease will occur.

Which of these substances are most important in the establishment of biofilms?

1. exotoxins
2. adhesins
3. siderophores
4. hemolysins
5. invasins

2. adhesins

Which one of these pairs is not correctly matched?

1. collagenase; breaks down connective tissue
2. coagulase; lyses fibrin clots
3. leukocidin; lyses WBC membranes
4. siderophore; traps iron
5. IgA protease; digest antibodies

2. coagulase; lyses fibrin clots

All of these answers are true of A-B exotoxins except ________.

1. Many exotoxins are A-B toxins.
2. They consist of two polypeptide components.
3. They are produced only by gram-negative bacteria.
4. The A portion of the toxin is the active component.
5. The B portion of the toxin binds to surface receptors on host cells.

3. They are produced only by gram-negative bacteria.

Which statement is true of endotoxins?

1. They are disease specific.
2. They are produced by gram-positive bacteria.
3. They are proteins.
4. They increase blood pressure.
5. They are released upon cell lysis.

5. They are released upon cell lysis.

Which statement is not true of endotoxins?
1. They are eliminated from the body as a result of antitoxin production.
2. They are more heat-resistant than exotoxins are.
3. They can lyse amoebocytes found in crab hemolymph.
4. They can induce chills, fever, aches, clotting, shock, and miscarriage.
5. Endotoxins are produced by Neisseria meningitidis and E. coli.

1. They are eliminated from the body as a result of antitoxin production.

Which of these viral cytopathic effects is most likely to be associated with the development of cancer?

1. cell fusion
2. stimulation of interferon production
3. inclusion bodies
4. loss of contact inhibition
5. cell death

4. loss of contact inhibition

Saxitoxin is produced by ________.

dinoflagellates

Most pathogens that gain access through the skin by _________

Entering through hair folicles and sweat ducts

the ID50 is _______

a dose that will cause an infection in 50% of the test population

Which of the following does not contribute to a pathogen's invasiveness?
A. Capsule
B. Hyaluronidase
C. Cell wall
D. Ligands
E. Exotoxins

E. Exotoxins

Which of the following statements is false?

A. Hyaluronidase breaks down substances between cells.
B. Hemolysins lyse red blood cells.
C. Kinase destroys fibrin clots.
D. Leukocidins destroy neutrophils.
E. Coagulase destroys blood clots.

E. Coagulase destroys blood clots.

Which of the following statements about exotoxins is generally not true?
A. They are more potent than endotoxins.
B. They are not inactivated by heat.
C. They are composed of proteins.
D. They are produced by gram-positive bacteria.
E. They have specific methods of action.

B. They are not inactivated by heat

Endotoxins are
A. Specific in their method of action.
B. Part of the gram-negative cell wall.
C. Associated with gram-positive bacteria.
D. Excreted from the cell.
E. None of the above.

B. Part of the gram-negative cell wall.

Cytopathic effects are changes in host cells due to
A. Bacterial infections.
B. Viral infections.
C. Protozoan and helminthic infections.
D. Fungal infections.
E. All of the above.

B. Viral infections.

All of the following are methods of avoiding host antibodies except
A. IgA protease.
B. Invasims.
C. Antigenic change.
D. Membrane-disrupting toxins.
E. None of the above

D. Membrane-disrupting toxins.

Siderophores are bacterial proteins that compete with animal ________

Transferrin

All of the following may be used for adherence except
A. Glycoproteins.
B. Lipoproteins.
C. Cell membrane mannose.
D. Fimbriae.
E. Capsules.

C. Cell membrane mannose.

A cell wall can increase a bacterium's virulence because cell wall lipid A
A. All bacteria have a cell wall and all are not pathogenic; therefore, cell walls do not contribute to virulence.
B. Helps the bacterium attach.
C. Resists phagocytosis.
D. Destroys host tissues.
E. None of the above.

E. None of the above.

Botulism is caused by an exotoxin, therefore it could easily be prevented by _________

Boiling food prior to consumption

Which of the following cytopathic effects is cytocidal?
A. Release of enzymes from lysosomes
B. Inclusion bodies
C. Antigenic changes
D. Giant cells
E. Transformation

A. Release of enzymes from lysosomes

Which of the following is not true of staphylococcal enterotoxin?
A. It is an exotoxin.
B. It causes diarrhea.
C. It causes vomiting.
D. It is produced by Staphylococcus aureus growing in the host's intestines.
E. None of the above.

D. It is produced by Staphylococcus aureus growing in the host's intestines.

All of the following are true about M protein except
A. It is heat- and acid-resistant.
B. It is a protein.
C. It is found on fimbriae.
D. It is found on Streptococcus pyogenes.
E. It is readily digested by phagocytes.

E. It is readily digested by phagocytes.

Septic shock due to gram-positive bacteria is caused by
A. Membrane-disrupting toxins.
B. A-B toxins.
C. Lipid A.
D. Superantigens.
E. All of the above.

D. Superantigens.

The most frequently used portal of entry for pathogens is the

Mucous membranes of the respiratory tracts

A needlestick is an example of what portal of entry

Parenteral

Cholera toxin polypeptide A binds to surface gangliosides on the target cell. If the gangliosides were removed

Polypeptide B would not be able to enter the cells

Antibiotics can lead to septic shock if used to treat

Gram-negative bacterial infections

Which of the following is not a cytopathic effect of viruses
A. Cell death
B. Increased cell growth
C. Inclusion bodies form in the cytoplasm or nucleus
D. Host cells fuse to form multinucleated syncytia
E. None of the above

E. None of the above

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