The time response measures all of the following except:
- A. ED50
- B. Peak effect time
- C. Onset of response
- D. Threshold level
Correct Answer: A
Rationale: The correct answer is A: ED50. The time response does not measure the ED50 because ED50 refers to the effective dose needed to produce a response in 50% of the population, which is a dose-related concept, not a time-related one. Peak effect time, onset of response, and threshold level are all time-related measures in pharmacology. Peak effect time is the time taken to reach the maximum response, onset of response is the time taken for the response to start, and threshold level is the minimum dose or concentration required to produce a response. Therefore, A is the correct answer as it is the only choice that is not a time-related measure in this context.
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Unlike eukaryotic cytoplasm, the prokaryotic one is:
- A. More complex
- B. Simpler
- C. There is no difference in the structure
- D. None of the above
Correct Answer: B
Rationale: The correct answer is B: Simpler. Prokaryotic cytoplasm is simpler than eukaryotic cytoplasm because prokaryotic cells lack membrane-bound organelles such as a nucleus, mitochondria, and endoplasmic reticulum that are present in eukaryotic cells. Prokaryotic cytoplasm contains fewer components and structures compared to eukaryotic cytoplasm, making it less complex. Therefore, the prokaryotic cytoplasm is simpler in structure. Choices A, C, and D are incorrect because prokaryotic cytoplasm is not more complex than eukaryotic cytoplasm, there is a clear difference in structure between prokaryotic and eukaryotic cytoplasm, and the statement "None of the above" is not accurate as the correct answer is B.
A 25-year-old patient reports pain, burning at urination and scarce secretion in the morning. Urine samples are taken and cultivated on blood and MacConkey agar. After 24 hours of incubation, the culture are sterile. Which one of the following bacteria is the most probable cause of this disease?
- A. Escherichia coli
- B. Chlamydia trachomatis
- C. Streptococcus pneumoniae
- D. Neisseria gonorrhoeae
Correct Answer: B
Rationale: The correct answer is B: Chlamydia trachomatis. This is because Chlamydia trachomatis is an obligate intracellular bacterium that cannot be cultured on standard agar plates. The symptoms described by the patient, such as pain, burning at urination, and scarce secretion in the morning, are indicative of a possible chlamydial infection. Additionally, the fact that the urine cultures are sterile after 24 hours of incubation suggests that the causative agent is not a typical bacteria like Escherichia coli, Streptococcus pneumoniae, or Neisseria gonorrhoeae, which would normally grow on agar plates. Therefore, Chlamydia trachomatis is the most probable cause of this disease.
Summary:
A: Escherichia coli - Incorrect, as it is a common cause of urinary tract infections and would typically grow on agar plates.
C: Streptococcus pneumoniae - Incorrect, as it is
Which of the following bacteria is responsible for causing the disease known as pneumonia?
- A. Streptococcus pneumoniae
- B. Mycobacterium tuberculosis
- C. Escherichia coli
- D. All of the above
Correct Answer: D
Rationale: Rationale:
1. Streptococcus pneumoniae is a common cause of bacterial pneumonia.
2. Mycobacterium tuberculosis can cause a type of pneumonia called tuberculosis.
3. Escherichia coli is not typically associated with pneumonia.
4. "All of the above" includes both Streptococcus pneumoniae and Mycobacterium tuberculosis, which are known to cause pneumonia. Therefore, D is the correct answer.
The most commonly acquired laboratory infections are caused by
- A. bacteria.
- B. viruses.
- C. protozoans.
- D. prions.
Correct Answer: A
Rationale: The correct answer is A: bacteria. Bacteria are the most common cause of laboratory-acquired infections due to their ability to survive and multiply in various environments. They can easily contaminate lab equipment and surfaces, leading to infections if proper precautions are not taken. Viruses (choice B) are less common in laboratory-acquired infections as they require specific conditions to survive outside a host. Protozoans (choice C) are larger and less likely to be transmitted in a laboratory setting. Prions (choice D) are misfolded proteins and are not considered living organisms, making them an unlikely source of laboratory infections.
Treponema pallidum and Borrelia burgdorferi belong to the group of:
- A. gram-negative aerobic rods and cocci
- B. anaerobic gram-negative rods
- C. anaerobic gram-negative cocci
- D. spirochetes
Correct Answer: D
Rationale: Step-by-step rationale:
1. Treponema pallidum and Borrelia burgdorferi are both spirochetes.
2. Spirochetes are characterized by their spiral shape and unique motility.
3. Both organisms exhibit corkscrew-like movement due to axial filaments.
4. Other choices are incorrect as Treponema and Borrelia are not gram-negative rods, cocci, or anaerobic cocci.
Summary:
The correct answer is D because Treponema pallidum and Borrelia burgdorferi are spirochetes, characterized by their spiral shape and motility. Other choices are incorrect as they do not accurately describe the characteristics of these organisms.