Question 1

A strain of Influenza A virus is resistant to treatment with oseltamivir. The most likely mechanism for this resistance is

Accepted Answer

A)  Decreased affinity for the M2 protein
B)  Inability to phosphorylate the antiviral
C)  Mutation in the neuraminidase gene
D)  Synthesis of a  β\betaβ -lactamase  C

Question 2

A cofactor in Burkitt's lymphoma is

Accepted Answer

A)   Cytomegalovirus infection
B)  Hepatitis A virus infection
C)  Hepatitis B virus infection
D)  Influenza virus type A infection
E)  Mycoplasma pneumoniae infectionF) Epstein-Barr virus infection F

Question 3

In the following pairs of organisms, which two are easiest to distinguish from each other by Gram stain?

Accepted Answer

A)  Bacillus and Clostridium
B)  Salmonella and Shigella
C)  Haemophilus and Escherichia
D)  Corynebacterium and Lactobacillus
E)  Listeria and Proteus E

Question 4

A 19-year-old college freshman has a sore throat, sore and enlarging cervical lymph nodes, and a fever. The student is also greatly fatigued. A diagnosis of infectious mononucleosis is made. Which of the following factors is present?

Accepted Answer

A)  Delta hemagglutinin
B)  E1A protein
C)  Large T antigen
D)  TAT protein
E)  VCA proteinF) Matrix protein

Question 5

Following neonatal thymectomy, you would expect

Accepted Answer

A)   Depletion of the periarteriolar region of the spleen
B)  Elimination of germinal center formation
C)  An increase in ability to reject skin grafts
D)  An increase in autoimmunity

Question 6

A 6-month-old infant has had watery diarrhea for 6 days; he vomited a couple of times. The stools have no blood and no pus. He is dehydrated. He has not been outside of Cincinnati. Two other toddlers who visited for a day also are sick. What is most likely causing this?

Accepted Answer

A)  Clostridium botulinum toxin
B)  Giardia lamblia
C)  Norwalk agent
D)  Rotavirus
E)  Salmonella enteritidisF) Staphylococcus aureus enterotoxin

Question 7

A 70-year-old woman presents with complaints of fatigue, nausea, fever, anorexia, and abdominal pains. Her travel history shows that she is recently back from a trip to western and central rural Mexico where she ate what everyone else was eating, including raw oysters from the coast. Physical examination shows a yellow tinge to her eyes, and her urine is dark. Lab studies show elevated liver enzymes. Blood cultures are negative for Vibrio vulnificus. Hepatitis serologies are: Antibody to hepatitis A virus: positive IgM antibody to hepatitis B core antigen: negative IgG antibody to hepatitis B core antigen: positive IgM antibody to hepatitis B surface antigen: negative IgG antibody to hepatitis B surface antigen: positive HBsAg: negative What is most likely causing her current problems?

Accepted Answer

A)  Hepatitis A
B)  Hepatitis B
C)  Hepatitis C
D)  Vibrio vulnificus
E)  Vibrio cholerae

Question 8

A hospitalized burn patient develops toxic shock syndrome. An enterotoxin secreting Staphylococcus is isolated from the burn lesion. This superantigen acts by

Accepted Answer

A)  Inducing the secretion of high concentrations of cytokines
B)  Blocking the epitope-binding region of HLA molecules
C)  Decreasing the numbers of polymorphonuclear cells
D)  Binding to the  VβV\betaVβ  region on multiple B cells

Question 9

A 7-year-old boy develops vesicular skin lesions on his trunk, which quickly spread to his extremities and appear on the scalp. Scrapings from the vesicles show multinucleated cells and Cowdry type A inclusion bodies. This disease could have been prevented with a vaccine composed of

Accepted Answer

A)  Capsid protein
B)  Inactivated virions
C)  Live attenuated virus strain
D)  Live reassortment virus
E)  Vaccinia virus carrying capsid protein gene

Question 10

The hospital blood bank desires to isolate stem cells from a patient with multiple myeloma for transplantation following his radiation treatment. The cell marker important for isolating and identifying human stem cells is

Accepted Answer

A)  CD3
B)  CD4
C)  CD28
D)  CD34

Question 11

An 18-year-old male college student came to the Student Health Services complaining of a sore throat, fatigue, and difficulty in swallowing. A physical examination showed an enlarged spleen; a palpable, tender liver; and swollen cervical lymph nodes. His blood is positive for heterophile antibody. What would you expect to see in a blood smear?

Accepted Answer

A)   Atypical T cells called Downey cells
B)   Gram-positive rods
C)   Gram-negative rods
D)   Mononuclear cells with Cowdry type A inclusions
E)   Multinucleated giant cells

Question 12

A new reverse transcriptase has been discovered. In addition to its effect on HIV disease, it should be checked for its potential in treating

Accepted Answer

A)  Infectious hepatitis
B)  Infectious mononucleosis
C)  Measles
D)  Serum hepatitis
E)  Shingles

Question 13

A 9-year-old girl presents with bloody diarrhea following a neighborhood barbeque. Her mother said the hamburgers were undercooked. Ultimately, a diagnosis of O157 strain of E. coli is made. Where are the O antigens found? In

Accepted Answer

A)   Capsule
B)   Lipopolysaccharide
C)   Lipoprotein
D)   Mesosome
E)   PeptidoglycanF)  Teichoic acid

Question 14

A typical IgG antibody molecule has all of the following characteristics except

Accepted Answer

A)  It consists of at least two identical heavy and two identical light chains
B)  It has two antigen-binding sites
C)  It has specificity for only one antigen
D)  It is a glycosylated molecule
E)  It has two constant domains on each of the heavy chains

Question 15

HLA II molecules play an important role in the immune response. One of their functions is

Accepted Answer

A)   To present peptidic epitopes to  CD4+CD4^+CD4+  T helper cells
B)   To present peptidic epitopes to  CD8+CD8^+CD8+  T helper cells
C)   To interact with an epitope on the membranes of most nucleated cells
D)   To interact with the gene regions: DP, DQ, DR

Question 16

An antibiotic that has a $\beta$-lactam ring in its structure is

Accepted Answer

A)   Tetracycline
B)   Cephalosporin
C)   Streptomycin
D)   Erythromycin
E)   GriseofulvinF)  Bacitracin

Question 17

Pepsin digestion of the IgG antibody against tetanus toxoid will

Accepted Answer

A)   Result in loss of the ability to form a lattice with the toxoid
B)   Produce two Fab molecules and one Fc fragment
C)   Result in a (Fab)  2 molecule and destruction of the Fc fragment
D)   Result in the loss of the Ch 1 heavy chain constant domain

Question 18

Which of the following interleukins is an endogenous pyrogen?

Accepted Answer

A)  IL-1
B)  IL-2
C)  IL-3
D)  IL-4
E)  IL-5

Question 19

A patient with a cough of several weeks' duration but no fever has radiological signs of a coin lesion. The needle biopsy shows large, broad-based budding yeasts with a very thick cell wall. Most of the yeasts are extracellular. What is the most likely diagnosis?

Accepted Answer

A)  Aspergillosis
B)  Blastomycosis
C)  Coccidioidomycosis
D)  Histoplasmosis
E)  Cancer

Question 20

Joe has been HIV positive for the past 6 years. His disease has been slowly progressing. Mike, his only partner for the past 3 years, is free of the disease. A plausible explanation for Mike's lack of infection would be

Accepted Answer

A)   His CD4/CD8 ratio is probably greater than 2
B)  He has a high concentration of NK cells that kill the virus
C)  He lacks the coreceptor CXCR4
D)  He has built up a high titer of anti-GP160 antibody

Exam 11: Travelers Diarrhea: Identifying the Causative Agent

A strain of Influenza A virus is resistant to treatment with oseltamivir. The most likely mechanism for this resistance is

A cofactor in Burkitt's lymphoma is

In the following pairs of organisms, which two are easiest to distinguish from each other by Gram stain?

A 19-year-old college freshman has a sore throat, sore and enlarging cervical lymph nodes, and a fever. The student is also greatly fatigued. A diagnosis of infectious mononucleosis is made. Which of the following factors is present?

Following neonatal thymectomy, you would expect

A 6-month-old infant has had watery diarrhea for 6 days; he vomited a couple of times. The stools have no blood and no pus. He is dehydrated. He has not been outside of Cincinnati. Two other toddlers who visited for a day also are sick. What is most likely causing this?

A hospitalized burn patient develops toxic shock syndrome. An enterotoxin secreting Staphylococcus is isolated from the burn lesion. This superantigen acts by

A 7-year-old boy develops vesicular skin lesions on his trunk, which quickly spread to his extremities and appear on the scalp. Scrapings from the vesicles show multinucleated cells and Cowdry type A inclusion bodies. This disease could have been prevented with a vaccine composed of

The hospital blood bank desires to isolate stem cells from a patient with multiple myeloma for transplantation following his radiation treatment. The cell marker important for isolating and identifying human stem cells is

A new reverse transcriptase has been discovered. In addition to its effect on HIV disease, it should be checked for its potential in treating

A 9-year-old girl presents with bloody diarrhea following a neighborhood barbeque. Her mother said the hamburgers were undercooked. Ultimately, a diagnosis of O157 strain of E. coli is made. Where are the O antigens found? In

A typical IgG antibody molecule has all of the following characteristics except

HLA II molecules play an important role in the immune response. One of their functions is

An antibiotic that has a $\beta$ -lactam ring in its structure is

Pepsin digestion of the IgG antibody against tetanus toxoid will

Which of the following interleukins is an endogenous pyrogen?

A patient with a cough of several weeks' duration but no fever has radiological signs of a coin lesion. The needle biopsy shows large, broad-based budding yeasts with a very thick cell wall. Most of the yeasts are extracellular. What is the most likely diagnosis?

Joe has been HIV positive for the past 6 years. His disease has been slowly progressing. Mike, his only partner for the past 3 years, is free of the disease. A plausible explanation for Mike's lack of infection would be

Exam 11: Travelers Diarrhea: Identifying the Causative Agent

A strain of Influenza A virus is resistant to treatment with oseltamivir. The most likely mechanism for this resistance is

A cofactor in Burkitt's lymphoma is

In the following pairs of organisms, which two are easiest to distinguish from each other by Gram stain?

A 19-year-old college freshman has a sore throat, sore and enlarging cervical lymph nodes, and a fever. The student is also greatly fatigued. A diagnosis of infectious mononucleosis is made. Which of the following factors is present?

Following neonatal thymectomy, you would expect

A 6-month-old infant has had watery diarrhea for 6 days; he vomited a couple of times. The stools have no blood and no pus. He is dehydrated. He has not been outside of Cincinnati. Two other toddlers who visited for a day also are sick. What is most likely causing this?

A hospitalized burn patient develops toxic shock syndrome. An enterotoxin secreting Staphylococcus is isolated from the burn lesion. This superantigen acts by

A 7-year-old boy develops vesicular skin lesions on his trunk, which quickly spread to his extremities and appear on the scalp. Scrapings from the vesicles show multinucleated cells and Cowdry type A inclusion bodies. This disease could have been prevented with a vaccine composed of

The hospital blood bank desires to isolate stem cells from a patient with multiple myeloma for transplantation following his radiation treatment. The cell marker important for isolating and identifying human stem cells is

A new reverse transcriptase has been discovered. In addition to its effect on HIV disease, it should be checked for its potential in treating

A 9-year-old girl presents with bloody diarrhea following a neighborhood barbeque. Her mother said the hamburgers were undercooked. Ultimately, a diagnosis of O157 strain of E. coli is made. Where are the O antigens found? In

A typical IgG antibody molecule has all of the following characteristics except

HLA II molecules play an important role in the immune response. One of their functions is

An antibiotic that has a β\betaβ -lactam ring in its structure is

Pepsin digestion of the IgG antibody against tetanus toxoid will

Which of the following interleukins is an endogenous pyrogen?

A patient with a cough of several weeks' duration but no fever has radiological signs of a coin lesion. The needle biopsy shows large, broad-based budding yeasts with a very thick cell wall. Most of the yeasts are extracellular. What is the most likely diagnosis?

Joe has been HIV positive for the past 6 years. His disease has been slowly progressing. Mike, his only partner for the past 3 years, is free of the disease. A plausible explanation for Mike's lack of infection would be

An antibiotic that has a $\beta$ -lactam ring in its structure is