Nokea
The process by which the nucleus of protozoans undergoes multiple divisions before the cell divides is called:
- A. budding
- B. mitosis
- C. schizogony
- D. fragmentation
Correct Answer: C
Rationale: Rationale: Schizogony is the process in protozoans where multiple nuclear divisions occur before cell division. This results in the formation of multiple daughter cells.
- A: Budding is a form of asexual reproduction where a new organism grows from an outgrowth on the parent.
- B: Mitosis is a type of cell division that results in two identical daughter cells.
- D: Fragmentation is a form of asexual reproduction where an organism breaks into fragments, each developing into a new organism.
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In which of the following cases of immune reactions a large lattice is formed?
- A. Antibody is in excess
- B. Antigens and antibodies are in optimal proportion
- C. Antigen is in excess
- D. None of the above
Correct Answer: B
Rationale: The correct answer is B because in immune reactions, a large lattice is formed when antigens and antibodies are in optimal proportion. This optimal ratio allows for the formation of a strong antigen-antibody complex, leading to the aggregation of immune complexes into large lattice structures. When antibodies are in excess (choice A), there may not be enough antigens to form a stable lattice. Similarly, when antigens are in excess (choice C), there may be insufficient antibodies to form a strong lattice. Choice D is incorrect because the optimal proportion of antigens and antibodies is crucial for the formation of large lattices in immune reactions.
A healthy man is in a region with high risk of catching malaria. What drug should be administered for individual chemoprophylaxis of malaria?
- A. Chingamin
- B. Sulfalen
- C. Tetracycline
- D. Metronidazole
Correct Answer: A
Rationale: The correct answer is A: Chingamin (also known as Chloroquine). Chingamin is the drug of choice for chemoprophylaxis of malaria in regions with high risk. It is effective against Plasmodium falciparum, the most common malaria parasite. Chingamin is well-tolerated, affordable, and has a long track record of use. Sulfalen (Choice B) is not commonly used for malaria prophylaxis. Tetracycline (Choice C) is not recommended for malaria prophylaxis due to poor efficacy and resistance development. Metronidazole (Choice D) is not effective against malaria parasites.
Which of the following statements for genus Klebsiella is correct?
- A. They have real capsule and are non-motile
- B. They are obligatory anaerobic
- C. They form spores only under aerobic conditions
- D. None of the above
Correct Answer: A
Rationale: The correct answer is A because Klebsiella species have a real capsule, which is a distinguishing feature used for their identification. This capsule helps them evade the host immune response. Additionally, Klebsiella species are non-motile, meaning they do not possess flagella for movement. Choices B and C are incorrect because Klebsiella species are facultative anaerobes and do not form spores under any conditions. Choice D is also incorrect as option A is the correct statement for genus Klebsiella.
Which of the following viruses belong to family Arenaviridae
- A. Lassa virus
- B. Crimean-Congo hemorrhagic fever virus
- C. Rabies virus
- D. Epstein-Bar virus
Correct Answer: A
Rationale: The correct answer is A: Lassa virus. The rationale is as follows:
1. Lassa virus is a member of the Arenaviridae family, known for causing Lassa fever.
2. Arenaviridae family includes viruses with a segmented genome and are transmitted through rodents.
3. Crimean-Congo hemorrhagic fever virus (Choice B) belongs to the Bunyaviridae family, not Arenaviridae.
4. Rabies virus (Choice C) belongs to the Rhabdoviridae family, not Arenaviridae.
5. Epstein-Barr virus (Choice D) belongs to the Herpesviridae family, not Arenaviridae.
In summary, Lassa virus is the correct choice as it aligns with the characteristics of the Arenaviridae family, while the other choices belong to different virus families.
Which of the following bacteria can be transmitted via droplets in the air?
- A. Streptococcus pneumoniae
- B. Escherichia coli
- C. Clostridium botulinum
- D. Mycobacterium tuberculosis
Correct Answer: D
Rationale: The correct answer is D: Mycobacterium tuberculosis. This bacterium can be transmitted via droplets in the air through coughing or sneezing. It is spread through respiratory droplets containing the bacteria. Streptococcus pneumoniae (A) is transmitted through direct contact with respiratory secretions, not through droplets in the air. Escherichia coli (B) is commonly transmitted through contaminated food or water, not through the air. Clostridium botulinum (C) is typically transmitted through contaminated food, not via respiratory droplets. Therefore, the correct choice is D as it is the only bacterium listed that can be transmitted via droplets in the air.