Nokea
All of the following are beta-lactam antibiotics except
- A. Benzylpenicillin
- B. Monobactam
- C. Cephalosporin
- D. Vancomycin
Correct Answer: D
Rationale: The correct answer is D, Vancomycin, because it is not a beta-lactam antibiotic. Beta-lactam antibiotics contain a beta-lactam ring in their molecular structure, which Vancomycin lacks. Benzylpenicillin, Cephalosporin, and Monobactam all contain the beta-lactam ring, making them beta-lactam antibiotics. Vancomycin belongs to a different class of antibiotics called glycopeptides.
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After the transfer of the F plasmid from the donor to the recipient cell..
- A. It is not possible to predict the outcome
- B. The donor cells become F
- C. The two cells become F
- D. The two cells become F+
Correct Answer: D
Rationale: After the transfer of the F plasmid from the donor to the recipient cell, the correct answer is D. This is because the F plasmid carries genes for conjugation, allowing the recipient cell to become F+ (containing the F plasmid). The donor cell remains F. Choice A is incorrect as the outcome can be predicted based on the transfer of the F plasmid. Choice B is incorrect because the donor cell does not become F after transferring the F plasmid. Choice C is incorrect as only the recipient cell becomes F+, not both cells.
It is planned to use the territory of an old cattle burial ground (which is not used for more than 50 years) for building houses. But ground analysis revealed presence of the pathogen of the very dangerous illness. Which of the indicated microorgonisms is likely to remain in the ground for such a long time?
- A. Mycobacterium bovis
- B. Brucella abortus
- C. Bacillus anthracis
- D. Francisella tularensis
Correct Answer: C
Rationale: Rationale:
1. Bacillus anthracis is a spore-forming bacterium that can survive for decades in the soil.
2. The spores are resistant to harsh conditions and can remain dormant for long periods.
3. This resilience allows Bacillus anthracis to persist in the old cattle burial ground for over 50 years.
4. Mycobacterium bovis, Brucella abortus, and Francisella tularensis are not known for long-term survival in soil.
Summary:
- Mycobacterium bovis, Brucella abortus, and Francisella tularensis do not have the spore-forming ability.
- Mycobacterium bovis causes tuberculosis in cattle.
- Brucella abortus causes brucellosis in cattle.
- Francisella tularensis causes tularemia in animals and humans.
Disinfection with chemicals acting on cell surface:
- A. Soaps
- B. Phenols
- C. Amines
- D. Polymyxin
Correct Answer: B
Rationale: The correct answer is B: Phenols. Phenols act on the cell surface by disrupting cell membranes and denaturing proteins, leading to cell death. Soaps (A) work by lifting dirt and microbes off surfaces, not directly acting on cell surfaces. Amines (C) are typically used as disinfectants targeting specific enzymes in microbes, not cell surfaces. Polymyxin (D) is an antibiotic that works by disrupting cell membranes internally, not on the cell surface.
Which one is not true for the adaptive immunity:
- A. Is mainly observed in the skin and mucous membranes
- B. Develops immune memory
- C. Has a specificity
- D. Evolutionary newer in comparison to the innate immunity
Correct Answer: A
Rationale: The correct answer is A because adaptive immunity is not mainly observed in the skin and mucous membranes. Adaptive immunity is a systemic response that involves specific immune cells and antibodies targeting specific pathogens. It develops immune memory (B), meaning it can recognize and respond faster upon re-exposure to the same pathogen. Adaptive immunity also has specificity (C), as it can target specific antigens. Lastly, adaptive immunity is not evolutionarily newer in comparison to innate immunity (D), as both systems have co-evolved to provide comprehensive protection against pathogens.
An 18-year-old patient has enlarged inguinal lymph nodes, they are painless, thickened on palpation. In the area of genital mucous membrane there is a small-sized ulcer with thickened edges and "laquer"bottom of greyish colour. What is the most probable diagnosis?
- A. Syphilis
- B. Tuberculosis
- C. Lepra
- D. Trophic ulcer
Correct Answer: A
Rationale: The correct answer is A: Syphilis. The presentation of painless inguinal lymph nodes, along with a small-sized ulcer with thickened edges and a "laquer" bottom of greyish color on the genital mucous membrane, is classic for primary syphilis. The painless nature of the lymph nodes and the specific characteristics of the ulcer are key features of syphilitic infection. Primary syphilis is caused by the bacterium Treponema pallidum and typically presents with a single, painless ulcer known as a chancre. It is important to consider syphilis in the differential diagnosis of genital ulcers.
Summary of other choices:
B: Tuberculosis - Unlikely, as tuberculosis typically presents with pulmonary symptoms and does not cause genital ulcers.
C: Lepra - Unlikely, as leprosy does not typically present with painless inguinal lymph nodes and the specific ulcer characteristics described.
D: Trophic ulcer - Unlikely