Nokea
The enzyme required for replication of viral RNA is:
- A. Reverse transcriptase
- B. DNA polymerase
- C. RNA-dependent RNA polymerase
- D. Ligase
Correct Answer: C
Rationale: The correct answer is C: RNA-dependent RNA polymerase. This enzyme is required for replicating viral RNA due to its ability to catalyze the synthesis of RNA using an RNA template. Reverse transcriptase (A) is used to transcribe RNA into DNA, not replicate viral RNA. DNA polymerase (B) is used for replicating DNA, not RNA. Ligase (D) is involved in joining DNA fragments, not in replicating viral RNA. Therefore, RNA-dependent RNA polymerase is the only enzyme that specifically performs the function required for replicating viral RNA.
You may also like to solve these questions
The causative agent of bacterial dysentery belongs to which of the following genera?
- A. Genus Shigella
- B. Genus Salmonella
- C. Genus Klebsiella
- D. None of the above
Correct Answer: A
Rationale: The correct answer is A: Genus Shigella. Shigella is known to be the causative agent of bacterial dysentery. It invades the intestinal lining, leading to symptoms like severe diarrhea and abdominal cramps. Salmonella (choice B) typically causes food poisoning, not dysentery. Klebsiella (choice C) is associated with pneumonia and urinary tract infections, not dysentery. "None of the above" (choice D) is incorrect as Shigella does belong to a specific genus responsible for bacterial dysentery.
Which of the following bacteria produce a neurotoxin that affects the nervous system?
- A. Clostridium botulinum
- B. Clostridium tetani
- C. Both A and B
- D. None of the above
Correct Answer: C
Rationale: Rationale: Both Clostridium botulinum and Clostridium tetani produce neurotoxins. Botulinum toxin affects the nervous system by blocking neurotransmitter release, causing paralysis. Tetanus toxin affects the nervous system by interfering with neurotransmitter release, leading to muscle stiffness and spasms. Therefore, Choice C is correct. Choices A and B alone are incorrect because they only mention one of the bacteria that produces a neurotoxin. Choice D is incorrect because both bacteria mentioned in Choices A and B produce neurotoxins.
Which bacteria are capable of producing spores that can survive extreme environmental conditions?
- A. Clostridium botulinum
- B. Bacillus anthracis
- C. Both A and B
- D. None of the above
Correct Answer: C
Rationale: The correct answer is C (Both A and B) because both Clostridium botulinum and Bacillus anthracis are capable of producing spores. Spores are highly resistant structures that allow bacteria to survive harsh environmental conditions. Clostridium botulinum and Bacillus anthracis produce spores as a survival mechanism when conditions become unfavorable. Choice A (Clostridium botulinum) is incorrect because it only represents one of the bacteria capable of producing spores. Choice B (Bacillus anthracis) is also incorrect as it alone does not encompass all bacteria capable of producing spores. Choice D (None of the above) is incorrect as both bacteria mentioned can produce spores.
In 8 days after a surgery the patient developed tetanus. The surgeon suspects this condition to be caused by suture material contaminated by tetanus agent. The material is delivered to a bacteriological laboratory. What nutrient medium is required for primary inoculation of the suture material?
- A. Kitt-Tarozzi medium.
- B. Endo agar.
- C. Sabouraud agar.
- D. Egg-yolk salt agar.
Correct Answer: A
Rationale: The correct answer is A: Kitt-Tarozzi medium. This medium is used for the primary inoculation of suture material suspected of causing tetanus. The rationale is that Kitt-Tarozzi medium contains the necessary nutrients to support the growth of Clostridium tetani, the bacterium responsible for tetanus. This medium is selective and helps in isolating the specific pathogen from the contaminated suture material.
Summary of other choices:
B: Endo agar is used for the isolation of Gram-negative bacteria from clinical and non-clinical samples.
C: Sabouraud agar is used for the isolation of fungi and yeast.
D: Egg-yolk salt agar is used for the detection of lipase-producing bacteria, particularly Staphylococcus aureus.
Which of the following statements concerning Neisseria Meningitidis is correct?
- A. Has no capsules
- B. It causes epidemic meningitis
- C. Grow on differential media
- D. Gram-positive rods
Correct Answer: B
Rationale: The correct answer is B: It causes epidemic meningitis. Neisseria Meningitidis is a bacterium that can cause meningitis, an infection of the protective membranes covering the brain and spinal cord. This bacterium is known to cause outbreaks or epidemics of meningitis, especially in crowded or close-contact settings. The other choices are incorrect because:
A: Neisseria Meningitidis does have a capsule, which helps it evade the immune system.
C: Neisseria Meningitidis grows on selective media like Thayer-Martin agar, not differential media.
D: Neisseria Meningitidis is a Gram-negative diplococcus, not a Gram-positive rod.