Microbiology Exam 4

Regarding the neurotoxigenic disease caused by Clostridium tetani, which of the followingis not correct? A) It is typically a foodborne disease. B) It causes spasmic paralysis, i.e., continual muscle contractions that cannot stop. C) The causative agent produces endospores. D) It inhibits release of neurotransmitter from inhibitory neurons.

A) It is typically a foodborne disease.

Chlamydia trachomatis is a bacterial STD that lives intracellularly within human host cells; what adaptive immune response would most likely prevail in this infection? A) cytotoxic T cells B) macrophages C) memory B cells D) plasma B cells E) defensins

A) cytotoxic T cells

Which of the following is not an integral part of the inflammatory process? A) dilation of blood vessels B) release of histamines, bradykinin, and prostaglandins C) extravasation D) decrease in the permeability of blood vessels in the area E) release of cytokines to attract cells of the immune system

A) dilation of blood vessels

Natural killer cells target: A) infected cells that have lost MHC surface proteins B) bacterial cells that are coated with complement C) infected cells bound with antibody D) extracellular viruses E) All the above

A) infected cells that have lost MHC surface proteins

Which is false regarding sexually transmitted diseases (STDs)? A) Elementary body: infectious, but non replicative form of Chlamydia B) Causative agent of syphilis is a Gram Negative diplococci, Treponema pallidum C) Diagnosis of gonorrhea: detection of bacteria in urethral discharge of males; females typically asymptomatic. D) Tertiary syphilis: advanced stage of untreated disease; characterized by dementia and/or heart problems E) None are false; all are true statements.

B) Causative agent of syphilis is a Gram Negative diplococci, Treponema pallidum

Herd immunity refers to everyone in a community becoming vaccinated to protect everyone against a particular disease. A) True B) False

B) False

Which statement is false concerning the plague? A) Yersinia pestis is the bacterium responsible for this disease. B) Plague epidemics occur when infected mosquitos transfer the disease from human to human. C) The septicemic form of the plague is not the most infectious form of the disease. D) Plague is an example of a systemic infection. E) Part of the disease process by the plague bacteria is the formation of buboes, due to the enlargement of lymph nodes.

B) Plague epidemics occur when infected mosquitos transfer the disease from human to human.

Which pair is not correctly matched? A) Hapten: not immunogenic by itself; requires a carrier protein B) Threshold dose: yields only a few B cells C) Immunogenic strength: protein > carbohydrate > DNA fragment D) Antigenpresenting cells: typically the way in which T cells see antigen E) Person with type B blood: has antiA antibodies in serum

B) Threshold dose: yields only a few B cells

Which of the following pairs is mismatched? A) Interferons: secreted by eukaryotic cells in response to intracellular infection, specifically viral infections. B) Toll Like receptors: they directly kill pathogens C) Defensins: form channels in bacterial cytoplasmic membranes, ultimately killing the cell D) Exogenous pyrogen: leads to an increase in the hypothalamic temperature set point E) Complement: more effective against Gramnegative cells

B) Toll Like receptors: they directly kill pathogens

All the following would be of benefit to extracellular pathogens, except A) the presence of a capsule B) ability to prevent the fusion of a phagosome and lysosome C) ability to prevent of opsonization D) ability to alter cell surface proteins via phase variation E) There are no exceptions; all are of benefit to extracellular pathogens.

B) ability to prevent the fusion of a phagosome and lysosome

Immunoprecipitation occurs when A) antigen is present in excess over antibody B) antigen and antibody ratios are approximately equal C) antibody is present in excess over antibody D) none of the above

B) antigen and antibody ratios are approximately equal

An organism found on human skin that derives benefit from the host but does not harm it is described as a/an: A) parasite B) commensalistic organism C) opportunistic pathogen D) pathogen E) mutualist

B) commensalistic organism

A certain pathogen is easily acquired by individuals, and has less than a 1% mortality rate among those unfortunate enough to acquire it. This pathogen is A) highly infectious and highly virulent. B) highly infectious and minimally virulent. C) minimally infectious and minimally virulent. D) minimally infectious and highly virulent. E) None of the above

B) highly infectious and minimally virulent.

Which of the following would be considered an aspect of the adaptive immune response? A) interferons B) lymphocytes C) defensins D) natural killer cells E) neutrophils

B) lymphocytes

Which of the following is not associated with innate immunity? A) Interferon secretion B) Action of natural killer cells C) Activation of cytotoxic T cells D) Engulfment of bacteria by neutrophils E) All are associated with innate immunity

C) Activation of cytotoxic T cells

Why is antibiotic treatment not typically prescribed for staphylococcal food poisoning? A) The bacterium is a multidrug resistant pathogen. B) No antibiotic is useful because its a mixed infection. C) No cells infect the body to cause the disease symptoms. D) The causative agent is a MRSA. E) None of the above.

C) No cells infect the body to cause the disease symptoms.

Antigens coated with antibody can lead to all the following, except A) complement activation B) phagocytosis C) movement of neutrophils out of capillary blood vessels during inflammation D) agglutination E) neutralization of toxin or block adherence of bacteria to tissues

C) movement of neutrophils out of capillary blood vessels during inflammation

In immunology, the term clonal selection best refers to: A) the multiple types of cells needed to generate an antigenic specific response B) the ability of one B cell to produce antibodies to multiple antigens C) the ability of a specific B cell subset to proliferate upon exposure to a specific epitope D) the ability of memory B cells to induce a quick secondary antibody response E) the process of opsonizing antigen for rapid phagocytic degradation

C) the ability of a specific B cell subset to proliferate upon exposure to a specific epitope

The figure above depicts different infection cycles. In regards to the mosquito borne disease, what is the reservoir? A) the mosquito B) the girl in B C) the deer D) the tick E) the man in A

C) the deer

Which of the following is not applicable to pathogenic strains of Staphylococcus aureus? A) It is a primary cause of skin infections. B) Many strains are resistant to conventional penicillin like antibiotics. C) It can cause gastroenteritis due to food poisoning. D) It is a common cause of sore throats. E) Toxic shock syndrome is attributable to this bacterium.

D) It is a common cause of sore throats.

The phenomenon of membrane ruffling carried out by Shigella and other bacteria, is depicted in the above photograph. Which is true regarding this process? A) It is a type of phagocytosis, leading to death of the bacterium. B) It allows the bacteria to remain outside the host cell. C) It is induced by the binding of antibodies to the bacterium. D) It is preceded by the injection of several bacterial proteins into the host cell. E) None are true statements.

D) It is preceded by the injection of several bacterial proteins into the host cell.

Which is not true of opsonization? A) It requires the presence of phagocytic cells B) It involves antibodies C) It can destroy encapsulated bacteria D) It is strictly a part of the adaptive immune response E) Two of the above are not true.

D) It is strictly a part of the adaptive immune response

Which pathogen:description pair is not correct? A) Giardia: protozoal pathogen that is transmitted in feces (to water) as a cyst form. B) Neisseria meningitidis: capsulated, central nervous system pathogen capable of crossing the bloodbrain barrier C) Mycobacterium tuberculosis: slowgrowing, acid fast bacterium that causes a chronic respiratory disease D) Streptococcus pneumoniae: primary cause of sore throats and also causes flesheating disease (i.e., necrotizing fasciitis) E) Streptococcus mutans: biofilmforming pathogen that can cause endocarditis following a dental procedure

D) Streptococcus pneumoniae: primary cause of sore throats and also causes flesh eating disease (i.e., necrotizing fasciitis)

Which of the following should be free from microbes in a healthy individual? A) nose B) mouth C) skin D) cerebrospinal fluid E) gastrointestinal tract

D) cerebrospinal fluid

BONUS Commensals do not need virulence factors to survive on their host because: A) they are well adapted for their specific niche B) they do not breach the host barriers and immune system C) they do not normally cause disease D) two of A, B, and C are correct E) A, B, and C are all correct

E) A, B, and C are all correct

Which statement is not accurate regarding bacterial exotoxins? A) Exotoxins are protein toxins made & secreted by both Grampositive and Gramnegative bacteria. B) Toxins with ADP ribosyltransferase activity produce different effects depending on the toxin type. C) The cholera toxin gene of pathogenic Vibrio cholera strains is acquired from a bacterial virus (i.e., bacteriophage). D) Exotoxins can be superantigens or proteases. E) All are accurate statements.

E) All are accurate statements.

Which of the following is not correct about malaria? A) Plasmodium species are the causative agents of malaria; they are protozoans. B) Plasmodium parasites avoid the immune system by constantly changing cell surface proteins. C) Malaria is an infection of the cardiovascular system. D) The Anopheles mosquito is the vector for transmission of malaria. E) All are correct statements.

E) All are correct statements.

Which of the following pathogens does not cause gastroenteritis/diarrhea? A) Escherichia coli Ol57:H7 B) Rotavirus C) Shigella D) Giardia E) All cause gastroenteritis/diarrhea.

E) All cause gastroenteritis/diarrhea.

Which of the following does not contribute to the virulence of a pathogen? A) Toxins B) Capsule C) Fimbriae/pili D) Numbers of microorganisms that gain access to a host E) All contribute to the virulence of a pathogen

E) All contribute to the virulence of a pathogen

BONUS Which of the following bacterial types can become an intracellular pathogen (either facultative or obligate) during the course of an infection? A) Chlamydia B) Salmonella C) Shigella D) Mycobacterium tuberculosis E) All the above

E) All the above

Consider the data for two pathogens, agent 1 and agent 2 shown on the graph above. Which of the following is true regarding this data? A) Lower LD50: Agent 1 B) Less virulent pathogen: Agent 2 C) Primary pathogen: cannot determine from this data D) Higher LD50: Agent 2 E) All the above are true.

E) All the above are true.

Which of the following is not a characteristic of B cells? A) Memory B cells are responsible for the enhanced secondary antibody response B) They have antibodies on their surfaces. C) Plasma B cells form and secrete antibodies. D) They originate in bone marrow. E) B cells can directly kill pathogenic microbes.

E) B cells can directly kill pathogenic microbes.

Endotoxins are A) Associated with lipid A of the LPS layer. B) Secreted from the cell. C) Associated with gram positive bacteria. D) Part of the gram negative cell wall. E) Two of the above are correct

E) Two of the above are correct

A woman falls and suffers a cut on her leg. The cut went through her skin and she is bleeding. Which of the following defense mechanisms will participate in eliminating contaminating microbes? A) mucociliary escalator (i.e., ciliated cells in trachea, lungs) B) normal skin flora C) acidic skin secretions D) lysozyme E) phagocytosis and the inflammatory response

E) phagocytosis and the inflammatory response

The figure above depicts different infection cycles. Accidental transmission is most likely indicated by: A) 2 B) 5 C) 3 D) 4 E) None of the above

NOT SURE

The figure above depicts an antibody. For the labeled areas, which pair below is correctly matched? (e is referring to the Fc stem region that includes both c and) A) Binds to bacterial surface protein: a and b B) Your IgG antibodies are all similar in these areas: a and b C) Can attach to a host cell (e.g., a macrophage): a and b D) Your IgM antibodies are all different in these areas: e E) Two of the above are matched correctly.

NOT SURE RECHECK B) Your IgG antibodies are all similar in these areas: a and b D) Your IgM antibodies are all different in these areas: e