MCB 100 Exam 3 Iclickers Questions With Complete
Solutions
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.
C. Make a mutation in the pil1 gene and see if the bacterium is
still virulent in chickens, but not in pigs.
D. Make a mutation in the pil1 gene and see if the bacterium is
still virulent in pigs, but not in chickens.
E. Make a mutation in the pil2 gene and see if the bacterium is
still virulent in both pigs and chickens. Correct Answers B.
Make a mutation in the pil2 gene and see if the bacterium is still
virulent in pigs, but not in chickens.
A mosquito bites a person who then develops fever and rash.
What type of transmission would this be?
A. Mechanical vector transmission
B. Vehicle transmission
C. Zoonotic transmission
D. Direct contact transmission
E. Biological vector transmission Correct Answers E.
Biological vector transmission
,According to this graph of cases per capita in the last 90 days,
which region in the US had the highest averages of cases per
capita between February and March?
A. West
B. Midwest
C. South
D. Northwest Correct Answers A. West
At what stage of phagocytosis does the move end at?
A. Adhesion
B. Ingestion
C. Maturation
D. Killing
E. Elimination Correct Answers B. Ingestion
C. Maturation
Carriers are dangerous because they exhibit all of the following
except:
A. they are asymptomatic.
B. they are symptomatic.
C. they are unaware that they are spreading disease.
D. they are difficult to identify and quarantine.
E. they more common in a population than most people think.
Correct Answers B. they are symptomatic.
Horizontal gene transfer in influenza is more likely to cause
__________?
A. Antigenic drift
B. Seasonal influenza strains
C. RNA viruses
, D. Antigenic shift
E. Endemic disease Correct Answers D. Antigenic shift
How can B-cells become activated to produce antibodies?
A. B-cells can become activated by macrophages.
B. B-cells can become activated by the complement system.
C. B-cells can become activated by cells that express the MHC-I
protein.
D. B-cells can become activated by directly binding antigen with
the B-cell receptor.
E. B-cells can become activated by T-cells secreting cytokines.
Correct Answers D. B-cells can become activated by directly
binding antigen with the B-cell receptor.
E. B-cells can become activated by T-cells secreting cytokines.
In which tissue location do T-cells mature?
A. Blood
B. Thymus
C. Tonsils
D. Lymph Nodes
E. Bone Marrow Correct Answers B. Thymus
Inside of which tissue do antibody producing B-cells mature?
A. Tonsils
B. Intestines
C. Thymus
D. Thymus Nodes
E. Bone Marrow Correct Answers E. Bone Marrow
Solutions
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.
C. Make a mutation in the pil1 gene and see if the bacterium is
still virulent in chickens, but not in pigs.
D. Make a mutation in the pil1 gene and see if the bacterium is
still virulent in pigs, but not in chickens.
E. Make a mutation in the pil2 gene and see if the bacterium is
still virulent in both pigs and chickens. Correct Answers B.
Make a mutation in the pil2 gene and see if the bacterium is still
virulent in pigs, but not in chickens.
A mosquito bites a person who then develops fever and rash.
What type of transmission would this be?
A. Mechanical vector transmission
B. Vehicle transmission
C. Zoonotic transmission
D. Direct contact transmission
E. Biological vector transmission Correct Answers E.
Biological vector transmission
,According to this graph of cases per capita in the last 90 days,
which region in the US had the highest averages of cases per
capita between February and March?
A. West
B. Midwest
C. South
D. Northwest Correct Answers A. West
At what stage of phagocytosis does the move end at?
A. Adhesion
B. Ingestion
C. Maturation
D. Killing
E. Elimination Correct Answers B. Ingestion
C. Maturation
Carriers are dangerous because they exhibit all of the following
except:
A. they are asymptomatic.
B. they are symptomatic.
C. they are unaware that they are spreading disease.
D. they are difficult to identify and quarantine.
E. they more common in a population than most people think.
Correct Answers B. they are symptomatic.
Horizontal gene transfer in influenza is more likely to cause
__________?
A. Antigenic drift
B. Seasonal influenza strains
C. RNA viruses
, D. Antigenic shift
E. Endemic disease Correct Answers D. Antigenic shift
How can B-cells become activated to produce antibodies?
A. B-cells can become activated by macrophages.
B. B-cells can become activated by the complement system.
C. B-cells can become activated by cells that express the MHC-I
protein.
D. B-cells can become activated by directly binding antigen with
the B-cell receptor.
E. B-cells can become activated by T-cells secreting cytokines.
Correct Answers D. B-cells can become activated by directly
binding antigen with the B-cell receptor.
E. B-cells can become activated by T-cells secreting cytokines.
In which tissue location do T-cells mature?
A. Blood
B. Thymus
C. Tonsils
D. Lymph Nodes
E. Bone Marrow Correct Answers B. Thymus
Inside of which tissue do antibody producing B-cells mature?
A. Tonsils
B. Intestines
C. Thymus
D. Thymus Nodes
E. Bone Marrow Correct Answers E. Bone Marrow
