microbiology chapter 10 test bank

Correct Answer: B

Rationale: Memory cells are not part of the non-specific immune response because they are a component of the specific immune response. Non-specific immune responses are immediate and target a broad range of pathogens, whereas memory cells are formed after exposure to a specific pathogen to provide a quicker and stronger response upon subsequent exposure. Lysozyme (A), Interferon (C), and Phagocytosis (D) are all part of the non-specific immune response. Lysozyme is an enzyme that destroys bacterial cell walls, interferon helps to inhibit viral replication, and phagocytosis involves the engulfing and destruction of pathogens by phagocytes. These responses are not specific to particular pathogens and are the body's first line of defense.

Correct Answer: A

Rationale: The correct answer is A: Sandfly. Cutaneous leishmaniasis is transmitted by the bite of infected sandflies. These tiny insects are known vectors for Leishmania parasites. Sandflies are active during dusk and night, feeding on blood from mammals, including humans. Tick (B), mosquito (C), and tsetse fly (D) are not vectors for Leishmania parasites. Ticks transmit diseases like Lyme disease, mosquitoes transmit diseases like malaria, and tsetse flies transmit African trypanosomiasis. Therefore, the correct vector for cutaneous leishmaniasis is the sandfly due to its specific role in transmitting the Leishmania parasite.

Correct Answer: A

Rationale: The correct answer is A: decompose hydrogen peroxide. Catalase is an enzyme that breaks down hydrogen peroxide into water and oxygen. This is important in bacteria to protect them from the harmful effects of hydrogen peroxide, a byproduct of metabolism. Choice B is incorrect as peptidoglycan synthesis is not the function of catalase. Choice C is incorrect as oxidative phosphorylation is a metabolic process unrelated to catalase function. Choice D is incorrect as endotoxin production is not a role of catalase.

Correct Answer: B

Rationale: The correct answer is B because the main target of the toxin produced by Vibrio cholerae is the epithelial cells of the small intestine. This toxin, known as cholera toxin, binds to the surface of these cells and disrupts their normal function, leading to the characteristic watery diarrhea seen in cholera. The other choices are incorrect because macrophages are not the main target, RBCs are not directly affected by the toxin, and the stomach epithelial cells are not specifically targeted by Vibrio cholerae toxin.

Correct Answer: C

Rationale: The correct answer is C: Escherichia coli. E. coli is the most common cause of acute cystitis. It typically presents with leukocytes and gram-negative bacilli in the urine. The green pigment production indicates pyocyanin, which is a characteristic of E. coli. Pseudomonas aeruginosa (A) can also produce green pigment, but it is less common in urinary tract infections. Proteus mirabilis (B) is associated with a swarming motility pattern on agar, not mucous colonies. Klebsiella pneumoniae (D) is associated with pneumonia and other respiratory infections, not cystitis.