microbiology chapter 12 test bank

Correct Answer: B

Rationale: The correct answer is B: abiogenesis. Spontaneous generation refers to the idea that living organisms can arise from non-living matter, which was disproven by Louis Pasteur. Abiogenesis specifically refers to the origin of life from non-living matter, making it synonymous with spontaneous generation. Biogenesis (A) is the principle that living organisms only come from other living organisms. Evolution (C) is the process of gradual change in species over time. Spontaneity (D) refers to happening without external cause and is not directly related to the concept of spontaneous generation.

Correct Answer: D

Rationale: The correct answer is D: Immunocomplex. In this case, the patient's symptoms of fever, joint pains, rash, and itch along with leukopenia and thrombocytopenia indicate a serum sickness reaction. This is a type III hypersensitivity reaction where antigen-antibody complexes deposit in tissues, leading to inflammation and tissue damage. The symptoms typically occur 1-2 weeks after exposure to the antigen. Anaphylactic reaction (choice A) is immediate and involves IgE antibodies. Cytotoxic reaction (choice B) involves destruction of cells by antibodies. Delayed hypersensitivity (choice C) usually takes 48-72 hours to develop and involves T-cells. Therefore, the correct answer is D as it aligns with the symptoms and timeline of a type III hypersensitivity reaction.

Correct Answer: C

Rationale: The correct answer is C: Inhibits protein synthesis. Exotoxin of C. Diphtheriae acts by inhibiting protein synthesis in host cells. This disrupts cellular functions and leads to tissue damage. Choice A is incorrect because acetylcholine release is not affected. Choice B is incorrect as it does not involve neurotransmitters. Choice D is incorrect as the exotoxin does have a specific mechanism.

Correct Answer: A

Rationale: The most probable diagnosis is Leptospirosis. The symptoms described align with the classic presentation of Leptospirosis, such as fever, muscle pain, headache, jaundice, and hemorrhages. The initial symptoms of chills, high fever, and muscle pain followed by jaundice and hemorrhages are characteristic of Leptospirosis. The presence of dark urine and low diuresis also point towards kidney involvement, which is common in Leptospirosis due to renal failure. Additionally, the patient's history of potential exposure to contaminated water or soil supports the diagnosis, as Leptospirosis is commonly transmitted through contact with infected animal urine. Summary of other choices: - Typhoid fever typically presents with sustained fever, abdominal pain, and constipation, not matching the symptoms described. - Virus A hepatitis usually presents with jaundice, but other symptoms such as muscle pain and hemorrhages are not typical. - Sepsis is a systemic response

Correct Answer: A

Rationale: The correct answer is A: Syphilitic granulomas (gummas). In the tertiary stage of syphilis, gummas, which are soft, tumor-like growths, can develop in various organs such as the skin, bones, liver, and brain. This stage typically occurs years after the initial infection and can lead to serious complications if left untreated. Purulent exudation from the urethra (B) is not specific to syphilis and may indicate other infections. Non-tender chancre (C) is characteristic of the primary stage of syphilis, not the tertiary stage. Diffuse maculopapular rash (D) is more commonly seen in the secondary stage of syphilis.