ATI RN
microbiology a systems approach test bank Questions
Question 1 of 5
What is the name of the enzyme that allows the bacteria to become resistant to most penicillins?
Correct Answer: C
Rationale: The correct answer is C: Beta lactamase. This enzyme is produced by bacteria to break down the beta-lactam ring structure of penicillins, rendering them ineffective. Beta lactam ring (A) is part of the penicillin molecule, not an enzyme. MRSA (B) stands for methicillin-resistant Staphylococcus aureus, a type of bacteria resistant to certain antibiotics, not an enzyme. Aminoglycoside ring (D) refers to a different class of antibiotics and is not related to penicillin resistance in bacteria.
Question 2 of 5
Which one is true for enteropathogenic E.coli?
Correct Answer: A
Rationale: The correct answer is A because enteropathogenic E. coli (EPEC) have fimbrial adhesins that help them bind to enterocytes in the intestines, leading to colonization and infection. This is a key virulence factor of EPEC. Explanation for why other choices are incorrect: B: EPEC typically cause watery diarrhea in infants, not bloody diarrhea similar to shigellosis. C: EPEC are not part of the normal intestinal flora; they are pathogenic bacteria. D: EPEC are not invasive and do not typically produce enterotoxin; they primarily adhere to the intestinal epithelium.
Question 3 of 5
Which of the following bacterial structures has endotoxic activity?
Correct Answer: A
Rationale: The correct answer is A: Lipopolysaccharides. Lipopolysaccharides (LPS) are major components of the outer membrane of Gram-negative bacteria and are known to have endotoxic activity. LPS can trigger a strong immune response leading to inflammation and septic shock. Choice B, Lipoproteins of Braun, are not known to have endotoxic activity. Choice C, Protein A, is a surface protein found in Staphylococcus aureus and is not associated with endotoxic activity. Choice D, None, is incorrect as LPS is indeed a bacterial structure with endotoxic activity.
Question 4 of 5
The complex of all biological processes/mechanisms is responsible for the state of steady internal, physical, chemical conditions in the living systems and defense against all foreign agents is known as:
Correct Answer: C
Rationale: Rationale for Correct Answer (C - Immunity): 1. Immunity refers to the body's ability to defend against foreign agents. 2. Homeostasis is the state of steady internal conditions, not specifically related to defense. 3. Infection is the invasion and multiplication of pathogens, not the overall defense mechanism. 4. Commensalism is a symbiotic relationship where one organism benefits without harming the other.
Question 5 of 5
The effect of which of the following toxins DOES NOT MANIFEST with neurological symptoms:
Correct Answer: D
Rationale: Certainly! The correct answer is D: Pertussis exotoxin. Pertussis toxin primarily affects the respiratory system causing whooping cough. It does not directly target the nervous system like the other toxins listed. Tetanospasmin causes muscle spasms, Diphtheria exotoxin affects the heart and nerves, and Botulinum exotoxin causes paralysis by blocking neurotransmitter release. Therefore, Pertussis exotoxin is the only toxin among the options that does not manifest with neurological symptoms.