Nokea
The function of catalase in bacteria is to:
- A. decompose hydrogen peroxide
- B. synthesize peptidoglycan
- C. assist in oxidative phosphorylation
- D. produce endotoxins
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.
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The major morphological form of the bacteria are:
- A. Cocci, rod-shaped and curved
- B. Staphylococci, streptococci, diplococci
- C. Basicili, spiralis, staphylococci
- D. None of the above
Correct Answer: A
Rationale: The correct answer is A because it accurately describes the major morphological forms of bacteria. Cocci are spherical, rod-shaped bacteria are called bacilli, and curved bacteria are spirilla. Staphylococci, streptococci, and diplococci are specific types of cocci, not major morphological forms. Basicili and spiralis are not common morphological forms of bacteria. Option D is incorrect as the other choices do represent major morphological forms of bacteria.
A man was admitted to the hospital on the 5th day of disease that manifested itself by jaundice, muscle aching, chill, nose bleedings. In course of laboratory diagnostics a bacteriologist performed darkfield microscopy of the patient's blood drop. Name a causative agent of this disease:
- A. Leptospira interrogans
- B. Borrelia dutlonii
- C. Calymmatobacterium granulomatis
- D. Bartonella bacilloformis
Correct Answer: A
Rationale: The correct answer is A: Leptospira interrogans. Darkfield microscopy is used to visualize spirochetes, which are spiral-shaped bacteria. Leptospira is a spirochete bacterium that causes leptospirosis, which presents with jaundice, muscle aching, chill, and nosebleeds. Leptospira is commonly transmitted through contact with contaminated water or soil.
B: Borrelia dutlonii causes Lyme disease, which is transmitted by ticks and does not typically present with jaundice or nosebleeds.
C: Calymmatobacterium granulomatis causes granuloma inguinale, a sexually transmitted infection that does not present with the symptoms described.
D: Bartonella bacilloformis causes Carrion's disease, which presents with fever, anemia, and skin lesions but not jaundice or nosebleeds.
All of the following infections may recur during pregnancy except:
- A. Epstein-Barr virus infections
- B. herpes simplex virus infections
- C. streptococcal infections
- D. polyomavirus infections
Correct Answer: D
Rationale: The correct answer is D: polyomavirus infections. Polyomavirus infections do not typically recur during pregnancy because once the virus infects the body, it remains latent without causing recurrent infections. In contrast, choices A, B, and C can recur during pregnancy due to their ability to reactivate from latency or reinfect the host. Epstein-Barr virus infections (choice A) can lead to infectious mononucleosis, herpes simplex virus infections (choice B) can cause recurrent genital or oral herpes outbreaks, and streptococcal infections (choice C) can result in recurrent throat or skin infections.
During the incubation period S. Typhi multiplies in the
- A. small intestine enterocytes
- B. lumen of the small intestine
- C. hepatocytes
- D. macrophages of the Peyer patches and the solitary follicles
Correct Answer: D
Rationale: The correct answer is D because during the incubation period of Salmonella Typhi infection, the bacteria multiply in the macrophages of the Peyer's patches and solitary follicles. This is supported by the fact that S. Typhi is an intracellular pathogen that targets the lymphoid tissues of the intestines. Macrophages in these areas serve as the primary host cells for the bacteria, allowing for their replication and evasion of the host immune response. Choices A, B, and C are incorrect because S. Typhi does not primarily multiply in the small intestine enterocytes, the lumen of the small intestine, or hepatocytes during the initial stages of infection.
Best drug to treat candida infections:
- A. Nystatin
- B. Penicillin
- C. Streptomycin
- D. Isoniazid
Correct Answer: A
Rationale: The correct answer is A: Nystatin. Nystatin is an antifungal medication specifically used to treat candida infections. It works by disrupting the cell membrane of the fungus, leading to its death. Penicillin (B) is an antibiotic effective against bacterial infections, not fungal. Streptomycin (C) is also an antibiotic used for bacterial infections. Isoniazid (D) is used to treat tuberculosis, not candida infections. Therefore, Nystatin is the best choice for treating candida infections due to its antifungal properties.