MCB 100 EXAM 3 QUESTIONS & ANSWERS
Which of the following is NOT a symptom of disease?
A. headache
B. dizziness
C. fever
D. nausea
E. cramps - Answers -C. fever
Which of the following is NOT a sign of disease?
A. fever
B. swelling
C. diarrhea
D. dizziness
E. rash - Answers -D. dizziness
What steps should a researcher take to establish a cause and effect relationship
between a pathogen and a lethal human illness?
A. Identify the causative pathogen
B. Obtain the pathogen from the disease outbreak patients
C. infect uninfected people and see if it causes similar disease
D. A and B only
E. A, B and C - Answers -A. Identify the causative pathogen
B. Obtain the pathogen from the disease outbreak patients
D. A and B only
Which of the following would make it not possible to satisfy all of Koch's postulates for a
particular microbe?
A. The microbe only infects nonhuman animals.
B. The microbe does not cause the same symptoms in all patients.
C. The identity of the microbe is in question.
D. The microbe cannot be isolate in pure culture.
E. The microbe's DNA can be PCR amplified from all tissues where disease has been
observed. - Answers -D. The microbe cannot be isolate in pure culture.
A commensal E. coli strain usually found as part of the normal gut microbiota of
chickens has a pilin gene (pil1) that is responsible for attaching and colonizing chicken
intestines. A clinical isolate of this E. coli strain recently isolated from sick pigs appears
to have a new pilin gene (pil2) that allows for infection in pigs. How would you most
directly test this hypothesis?
A. Make a mutation in the pil2 gene and see if the bacterium is still virulent in chickens,
but not in pigs
B. Make a mutation in the pil2 gene and see if the bacterium is still virulent in pigs, but
not in chickens.
Which of the following is NOT a symptom of disease?
A. headache
B. dizziness
C. fever
D. nausea
E. cramps - Answers -C. fever
Which of the following is NOT a sign of disease?
A. fever
B. swelling
C. diarrhea
D. dizziness
E. rash - Answers -D. dizziness
What steps should a researcher take to establish a cause and effect relationship
between a pathogen and a lethal human illness?
A. Identify the causative pathogen
B. Obtain the pathogen from the disease outbreak patients
C. infect uninfected people and see if it causes similar disease
D. A and B only
E. A, B and C - Answers -A. Identify the causative pathogen
B. Obtain the pathogen from the disease outbreak patients
D. A and B only
Which of the following would make it not possible to satisfy all of Koch's postulates for a
particular microbe?
A. The microbe only infects nonhuman animals.
B. The microbe does not cause the same symptoms in all patients.
C. The identity of the microbe is in question.
D. The microbe cannot be isolate in pure culture.
E. The microbe's DNA can be PCR amplified from all tissues where disease has been
observed. - Answers -D. The microbe cannot be isolate in pure culture.
A commensal E. coli strain usually found as part of the normal gut microbiota of
chickens has a pilin gene (pil1) that is responsible for attaching and colonizing chicken
intestines. A clinical isolate of this E. coli strain recently isolated from sick pigs appears
to have a new pilin gene (pil2) that allows for infection in pigs. How would you most
directly test this hypothesis?
A. Make a mutation in the pil2 gene and see if the bacterium is still virulent in chickens,
but not in pigs
B. Make a mutation in the pil2 gene and see if the bacterium is still virulent in pigs, but
not in chickens.
