Nokea
A 19 year old woman suffers from primary syphilis. Doctor administered her complex therapy that includes benzylpenicillin sodium salt. What is the mechanism of action of this drug?
- A. It blocks synthesis of peptidoglycan of microbial membrane
- B. It blocks synthesis of cytoplasm proteins
- C. It blocks thiol enzymes
- D. It blocks RNA synthesis
Correct Answer: A
Rationale: The correct answer is A. Benzylpenicillin sodium salt, also known as penicillin G, works by blocking the synthesis of peptidoglycan in the microbial cell wall. Peptidoglycan is crucial for the structural integrity of bacterial cell walls. By inhibiting its synthesis, penicillin disrupts the cell wall formation, leading to cell lysis and bacterial death. Choices B, C, and D are incorrect because penicillin does not target cytoplasm proteins, thiol enzymes, or RNA synthesis. Penicillin's primary mode of action is specifically related to interfering with bacterial cell wall synthesis.
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Gram staining is used to differentiate bacteria based on:
- A. size and shape
- B. presence of flagella
- C. cell wall composition
- D. genetic material
Correct Answer: C
Rationale: The correct answer is C: cell wall composition. Gram staining differentiates bacteria based on the structure of their cell walls. It classifies bacteria into Gram-positive (thick peptidoglycan layer) and Gram-negative (thin peptidoglycan layer). This differentiation is crucial for identifying bacterial species and guiding treatment choices. Size and shape (choice A) are not specific to Gram staining. Presence of flagella (choice B) is related to bacterial motility, not Gram staining. Genetic material (choice D) is not directly assessed by Gram staining. Overall, the unique composition of the cell wall is the key factor in distinguishing bacteria through Gram staining.
OSHA is a division of the
- A. National Institutes of Health.
- B. Centers for Disease Control and Prevention.
- C. U.S. Department of Labor.
- D. World Health Organization.
Correct Answer: C
Rationale: 1. OSHA stands for Occupational Safety and Health Administration.
2. OSHA is responsible for ensuring safe and healthy working conditions in the US.
3. The U.S. Department of Labor oversees OSHA's operations and regulations.
4. Therefore, the correct answer is C, as OSHA is a division of the U.S. Department of Labor.
5. Other choices are incorrect because they are not directly related to OSHA's jurisdiction or responsibilities.
Bacteriophages are:
- A. White blood cells that kill bacteria
- B. Bacteria that invade other bacteria
- C. Viruses that infect bacteria
- D. Bacteria that infect fungi
Correct Answer: C
Rationale: The correct answer is C: Bacteriophages are viruses that infect bacteria. Firstly, bacteriophages are viruses, not white blood cells or bacteria. They specifically target and infect bacteria, not fungi. This is known as a bacteriophage cycle where the virus injects its genetic material into the bacterial cell to replicate and eventually lyse the cell. This process is specific to bacteria and distinguishes bacteriophages from other microorganisms. Therefore, the correct answer is C as it accurately describes the nature and function of bacteriophages.
The most common causative agent of bacterial meningitis are:
- A. E. Coli K1, Streptococcus group B (S. agalactiae), Listeria monocytogenes
- B. Haemophilus influenzae, Streptococcus pneumoniae, Neisseria meningitidis
- C. Staphylococcus aureus, pseudomonas aeruginosa
- D. None of the above
Correct Answer: B
Rationale: The correct answer is B because Haemophilus influenzae, Streptococcus pneumoniae, and Neisseria meningitidis are the most common causative agents of bacterial meningitis. Haemophilus influenzae is often seen in children, Streptococcus pneumoniae is the most common in adults, and Neisseria meningitidis is common in adolescents and young adults.
Choice A is incorrect because although Streptococcus group B and Listeria monocytogenes can cause meningitis, E. Coli K1 is not a common causative agent. Choice C is incorrect because Staphylococcus aureus and Pseudomonas aeruginosa are not typically associated with bacterial meningitis. Choice D is incorrect as there are known causative agents for bacterial meningitis.
Native microscopic slides are good for observation of:
- A. Motility
- B. Division
- C. Presence of capsules
- D. None of the above
Correct Answer: A
Rationale: The correct answer is A: Motility. Native microscopic slides are ideal for observing motility because they allow for the observation of living microorganisms in their natural state. By observing the movement of microorganisms on a native slide, one can assess their motility characteristics accurately.
Choice B (Division) is incorrect because native slides may not provide the ideal conditions for observing cell division, as it may be difficult to capture the exact moment of division in a live organism.
Choice C (Presence of capsules) is also incorrect because observing capsules usually requires specific staining techniques that may not be suitable for native slides.
Choice D (None of the above) is incorrect as native slides are indeed beneficial for observing motility.