Nokea
The catarrhal stage of the whooping cough is characterized by:
- A. Decrease in paroxysms of coughing
- B. Subsequent respiratory infection for many months after the onset of pertussis
- C. Uncontrollable coughing followed by a high pitched 'whoop' sound
- D. Mild respiratory symptoms (mild coughing, sneezing or a runny nose)
Correct Answer: D
Rationale: The correct answer is D because the catarrhal stage of whooping cough is characterized by mild respiratory symptoms such as mild coughing, sneezing, or a runny nose. During this stage, the cough may start to worsen but is not yet severe.
A: Incorrect - Decrease in paroxysms of coughing is not seen in the catarrhal stage; it occurs later in the paroxysmal stage.
B: Incorrect - Subsequent respiratory infection for many months after the onset of pertussis is not a characteristic of the catarrhal stage.
C: Incorrect - Uncontrollable coughing followed by a high pitched 'whoop' sound is typical of the paroxysmal stage, not the catarrhal stage.
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Infectious agents of various ultrastructures can be etiological agents of infectious diseases. Which of the groups named below HAS NO cellular structure, protein synthesizing, enzyme and energy systems?
- A. Viruses
- B. Fungi
- C. Bacteria
- D. Protozoa
Correct Answer: A
Rationale: The correct answer is A: Viruses. Viruses are acellular, meaning they lack cellular structure, protein synthesizing ability, enzymes, and energy systems. They are essentially genetic material (DNA or RNA) enclosed in a protein coat. Fungi (B), bacteria (C), and protozoa (D) are all cellular organisms with protein synthesizing, enzyme, and energy systems. Viruses rely on host cells to replicate and carry out metabolic functions, making them distinct from other groups.
How soon do symptoms typically appear after a person is infected with rabies virus
- A. 48 hours
- B. 1 week
- C. 1 month
- D. 1-2 years
Correct Answer: D
Rationale: The correct answer is D: 1-2 years. Rabies has a long incubation period before symptoms appear due to the slow progression of the virus within the body. The virus travels along nerve fibers to the brain, which can take months to years. During this time, the virus replicates and spreads, eventually leading to symptoms. Choices A, B, and C are incorrect as they underestimate the incubation period of rabies. Symptoms typically do not appear as early as 48 hours, 1 week, or 1 month after infection with the rabies virus.
Microscopic examination of dental plaque revealed unicellular organisms with two layers in their cytoplasm and wide pseudopodia. What is the likely causative agent?
- A. Entamoeba gingivalis
- B. Entamoeba histolytica
- C. Trichomonas tenax
- D. Lamblia intestinalis
Correct Answer: A
Rationale: Rationale:
1. Unicellular organisms with two layers in cytoplasm = Entamoeba gingivalis.
2. Wide pseudopodia = characteristic of Entamoeba genus.
3. Entamoeba histolytica causes amoebic dysentery, not dental plaque.
4. Trichomonas tenax causes periodontal disease, not dental plaque.
5. Lamblia intestinalis causes giardiasis, not related to dental plaque.
Gram-positive spore-forming bacilli were extracted in anoxic environment from the patient's wound contaminated with soil. Cultivation on a blood-glucose agar resulted in growth of the colonies surrounded with hemolysis zone. What agent was extracted from the wound?
- A. Clostridium perfringens
- B. Clostridium botulinum
- C. Staphylococcus aureus
- D. Pseudomonas aeruginosa
Correct Answer: A
Rationale: The correct answer is A: Clostridium perfringens. Clostridium perfringens is a gram-positive spore-forming bacillus commonly found in soil. It produces hemolysis on blood agar, as described in the question. Clostridium botulinum is also a gram-positive spore-forming bacillus, but it does not typically cause hemolysis. Staphylococcus aureus is a gram-positive cocci, not a bacillus. Pseudomonas aeruginosa is a gram-negative bacterium, not a gram-positive spore-forming bacillus.
Which fact is correct about the nucleoids in bacteria:
- A. Contain a haploid bacterial chromosomes in each nucleus
- B. Are reabsorbed well by the method of Neisser
- C. Are 1 to 4 in each bacterial cell depending on the nature of the cell and the phases of growth and replication
- D. None of the above
Correct Answer: C
Rationale: The correct answer is C because nucleoids in bacteria can vary in number from 1 to 4 depending on the specific bacterial cell and its growth and replication phases. This is due to the dynamic nature of bacterial cells and their genetic material organization.
Choice A is incorrect because nucleoids do not contain nuclear membranes or multiple haploid chromosomes like eukaryotic nuclei. Choice B is incorrect as there is no known method of reabsorbing nucleoids by Neisser. Choice D is incorrect as option C is indeed the correct statement regarding the number of nucleoids in bacterial cells.