MMG 301- Unit 3 end of unit self-
evaluation with complete solutions
2025/2026
Short answer question (only 1 to 3 sentences per part are necessary): Phagocytes are antigen
presenting cells (APCs) that recognize pathogens. Describe how this recognition occurs at the
molecular level and why this keeps APCs from harming host cells. - correct answer ✔✔APCs
express pattern recognition receptors (PRRs) that recognize and bind (conserved) pathogen
associated molecular patterns (PAMPs - credit also for naming LPS/peptidoglycan, flagella, viral
capsids). These molecular patterns are present only on pathogens thus, the APCs do not attack
host cells.
Short answer question (only 1 to 3 sentences per part are necessary): Researchers tested the
effects of vaccinating cattle against E. coli O157:H7 by measuring the probability of detecting
this bacterium in samples from the rectum of cattle who were vaccinated vs. control cattle (no
vaccination). See the figure below.
From these results, state if this vaccination of cattle would lead to the reduction in the number
of human cases of E. coli O157:H7? Use the data provided here and what was learned in class to
justify your answer. - correct answer ✔✔Vaccination reduced the probability of finding O157:H7
in the cattle gut. This would result in less O157:H7 contamination of the beef during processing,
and this would lead to fewer cases in the human consumers.
Which of these pathogens is best represented by this diagram of pathogenesis? - correct answer
✔✔Human Papilloma virus
Coagulase - correct answer ✔✔Creates a fibrin layer that prevents detection by the immune
system
Streptokinase - correct answer ✔✔Destroys fibrin bloods
, NDM-1 - correct answer ✔✔Cleaves beta-lactam antibiotics
mecA - correct answer ✔✔Beta-lactams cannot bind to the enzyme
This toxin blocks release of the inhibitory signal (glycine) from the inhibitory neuron that tells
the primary neuron to stop excreting the muscle stimulant (acetylcholine). - correct answer
✔✔Tetanus toxin
An inactivating mutation in which gene would cause isoniazid to no longer kill the bacterial cell?
- correct answer ✔✔KatG
PulseNet - correct answer ✔✔A database of Pulsed Field Gel Electrophoresis patterns of
pathogens that cause foodborne outbreaks.
FoodNet - correct answer ✔✔A surveillance database system that monitors foodborne disease
diagnoses in a subset of the US population
Genome Trakr - correct answer ✔✔A whole genome sequencing program for monitoring
foodborne illness outbreaks
A patient comes into your emergency room complaining of profuse vomiting and diarrhea.
Upon interviewing the patient, you learn that they ate at local establishment notorious for using
unsanitary methods of food preparation.
You attempt to isolate the pathogen from the feces using culture dependent methods and
multiple selective and differential media you learned in MMG 301. However, no bacterial
colonies associated with pathogens are observed. Based on these results you suspect the cause
of the disease is: - correct answer ✔✔Staphylococcus aureus food poisoning
evaluation with complete solutions
2025/2026
Short answer question (only 1 to 3 sentences per part are necessary): Phagocytes are antigen
presenting cells (APCs) that recognize pathogens. Describe how this recognition occurs at the
molecular level and why this keeps APCs from harming host cells. - correct answer ✔✔APCs
express pattern recognition receptors (PRRs) that recognize and bind (conserved) pathogen
associated molecular patterns (PAMPs - credit also for naming LPS/peptidoglycan, flagella, viral
capsids). These molecular patterns are present only on pathogens thus, the APCs do not attack
host cells.
Short answer question (only 1 to 3 sentences per part are necessary): Researchers tested the
effects of vaccinating cattle against E. coli O157:H7 by measuring the probability of detecting
this bacterium in samples from the rectum of cattle who were vaccinated vs. control cattle (no
vaccination). See the figure below.
From these results, state if this vaccination of cattle would lead to the reduction in the number
of human cases of E. coli O157:H7? Use the data provided here and what was learned in class to
justify your answer. - correct answer ✔✔Vaccination reduced the probability of finding O157:H7
in the cattle gut. This would result in less O157:H7 contamination of the beef during processing,
and this would lead to fewer cases in the human consumers.
Which of these pathogens is best represented by this diagram of pathogenesis? - correct answer
✔✔Human Papilloma virus
Coagulase - correct answer ✔✔Creates a fibrin layer that prevents detection by the immune
system
Streptokinase - correct answer ✔✔Destroys fibrin bloods
, NDM-1 - correct answer ✔✔Cleaves beta-lactam antibiotics
mecA - correct answer ✔✔Beta-lactams cannot bind to the enzyme
This toxin blocks release of the inhibitory signal (glycine) from the inhibitory neuron that tells
the primary neuron to stop excreting the muscle stimulant (acetylcholine). - correct answer
✔✔Tetanus toxin
An inactivating mutation in which gene would cause isoniazid to no longer kill the bacterial cell?
- correct answer ✔✔KatG
PulseNet - correct answer ✔✔A database of Pulsed Field Gel Electrophoresis patterns of
pathogens that cause foodborne outbreaks.
FoodNet - correct answer ✔✔A surveillance database system that monitors foodborne disease
diagnoses in a subset of the US population
Genome Trakr - correct answer ✔✔A whole genome sequencing program for monitoring
foodborne illness outbreaks
A patient comes into your emergency room complaining of profuse vomiting and diarrhea.
Upon interviewing the patient, you learn that they ate at local establishment notorious for using
unsanitary methods of food preparation.
You attempt to isolate the pathogen from the feces using culture dependent methods and
multiple selective and differential media you learned in MMG 301. However, no bacterial
colonies associated with pathogens are observed. Based on these results you suspect the cause
of the disease is: - correct answer ✔✔Staphylococcus aureus food poisoning
