Question: How are immune cells able to detect foreign pathogens?

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

Question: How does a capsule help certain bacteria evade detection by the immune system?

Answer: 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.

Question: Which of the following microorganisms actually grows inside the macrophage?

Answer: Tuberculosis bacterium

Question: How does the protozoan Trypanosoma evade detection by the immune system?

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

Question: What are leukocidins?

Answer: Molecules that are capable of destroying phagocytes

Question: Measles viruses are capable of inactivating host defenses by

Answer: suppressing the immune system.

Question: Meningitis and gonorrhea are caused by

Answer: Neisseria species.

Question: How do superantigens enable pathogens to hide from the immune system if they actually stimulate the immune system?

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

Question: How can capsules enable bacteria to evade the immune system?

Answer: Capsules block the complement biding sites on the surface of the pathogen.

Question: Endotoxins are also known as

Answer: lipid A

Question: When would endotoxins be released from a bacterial cell?

Answer: When the cell dies

Question: Which of the following would be the first sign of an infection that resulted in the release of endotoxin?

Answer: fever

Question: Why is a release of endotoxin into the bloodstream potentially deadly?

Answer: It can lower blood pressure and cause the patient to go into shock

Question: An exotoxin that has the ability to kill or damage host cells is referred to as a(n)

Answer: cytotoxin

Question: Which domain of the A-B toxin binds to cell surface receptors on the host cell?

Answer: b domain

Question: How are superantigens different from other types of exotoxins?

Answer: Superantigens cause an overstimulation of the host immune system.

Question: 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)

Answer: superantigen

Question: A patient who has been hospitalized with uncontrolled muscle spasms has probably been infected with bacteria that secrete a(n)

Answer: neurotoxin

Question: Which of the following would be an example of an infection initiated via the parenteral route?

Answer: An individual contracts hepatitis B from an accidental stick with a contaminated needle

Question: In which of the following cases would the Limulus amebocyte lysate (LAL) assay be used?

Answer: to ensure that a sterilized medical device is free of endotoxin

Question: Which disease would be potentially propagated in an environment without functional plumbing and in which drinking water is contaminated with sewage?

Answer: cholera

Question: Which of the following statements about lysogenic conversion is true?

Answer: Exotoxin production by bacteria is frequently the result of a lysogenic infection.

Question: Which of the following are requirements for causing disease within a host?

Answer: -gaining access to the host via a portal of entry-adherence to host tissues-evasion of host defenses

Question: Which of the following are properties of exotoxins?

Answer: -Exotoxins target specific cellular structures or molecules.-Exotoxins are protein molecules.-Very small amounts of exotoxin can be lethal.

Question: Which of the following statements are true?

Answer: -Some pathogens are able to cause disease within a host without penetrating the body.-Bacterial exotoxins can be altered to create toxoids, which can be used to produce protective immunity in a host.-The interactions that occur between a microbe and host influence the evolution of both

Question: capsules

Answer: This viscous outer covering found in certain microorganisms helps pathogens evade the host 19s defenses by impairing phagocytosis

Question: cell wall components

Answer: These structures contain substances that contribute to a pathogen 19s virulence; for example, M protein mediates microbial attachment to epithelial cells.

Question: enzymes

Answer: These proteins contribute to a pathogen 19s virulence by, for example, forming and breaking down fibrin clots, breaking down connective proteins, and countering certain types of antibodies.

Question: antigenic variation

Answer: This process allows pathogens to alter their surface antigens to avoid attack by antibodies produced by the immune system.

Question: invasins

Answer: These microbial surface proteins rearrange the host cell 19s actin filaments, allowing pathogens to enter and move in and between cells.

Question: siderophores

Answer: These proteins bind up iron obtained from the host cell 19s iron-transport proteins and transport this iron to bacteria through interactions with cell surface receptors.

Question: direct damage

Answer: This occurs as a result of nutrient depletion, accumulation of waste products, pathogen entry and exit, and ruptured host cells

Question: toxins

Answer: these poisonous substances cause most of the damage to host cells; they can be transported by the blood or lymph and may produce far-reaching effects

Question: lysogenic conversion

Answer: This results in a change in microbe characteristics due to the presence of prophage genes that confer new properties

Question: cytopathic effects

Answer: These describe the visible effects of viral infections that results in host cell damage.

Question: look at question 13 part A

Answer: ...

Question: Which of the following strategies might be used to block the activity of an A-B toxin?

Answer: -blocking host cell receptors to which A-B toxins bind-blocking receptor-mediated endocytosis in cells targeted by the A-B toxin-inhibiting the secretion of proteins from a bacterial cell-blocking separation of the A and B components of the toxin-blocking the binding sites on the B portion of an A-B toxin-

Question: Select all of the strategies that would be likely to block or reduce the harmful effects of superantigen toxins.

Answer: -blocking molecular determinants on superantigens that interacts with T cells-blocking the release of cytokines from T cells-blocking secretion of proteins by bacterial cells-neutralizing circulating cytokines

Question: Antibiotics can lead to septic shock if used to treat

Answer: gram-negative bacterial infections.

Question: The M protein enhances the virulence of Streptococcus by preventing phagocytosis.

Answer: TRUE

Question: In general, the LD50 for exotoxins is much greater than the LD50 for endotoxins.

Answer: FALSE

Question: Biofilms provide pathogens with an adhesion mechanism and aid in resistance to antimicrobial agents

Answer: TRUE

Question: The Limulus amoebocyte assay is used to detect minute amounts of endotoxin in drugs and medical devices.

Answer: TRUE