Artificial active immunity occurs after a vaccination: injecting or taking antigens by mouth. Takes time for T and B cells to be activated but gives relatively long lasting:
- A. TRUE
- B. FALSE
- C. Both answers can be correct depending on the given situation
- D. None of the above
Correct Answer: A
Rationale: 1. Vaccination introduces antigens to stimulate immune response.
2. T and B cells are activated to produce memory cells for long-lasting protection.
3. Active immunity develops over time post-vaccination.
4. Choice A is correct as it accurately describes the process and outcomes.
5. Choice B is incorrect as it contradicts the process of active immunity.
6. Choice C is incorrect as the process of active immunity is consistent regardless of the situation.
7. Therefore, the correct answer is A as it aligns with the mechanism and characteristics of artificial active immunity.
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Microscopy of a sputum smear from a pneumonia patient revealed Gram-positive diplococci with pointed ends surrounded by a capsule. What is the causative agent?
- A. Streptococcus pneumoniae
- B. Klebsiella pneumoniae
- C. Neisseria meningitidis
- D. Staphylococcus aureus
Correct Answer: A
Rationale: The correct answer is A: Streptococcus pneumoniae.
1. Gram-positive diplococci with pointed ends: characteristic morphology of Streptococcus pneumoniae.
2. Surrounded by a capsule: S. pneumoniae is encapsulated, important for virulence.
3. Klebsiella pneumoniae (B) is a Gram-negative rod, Neisseria meningitidis (C) is a Gram-negative diplococcus, and Staphylococcus aureus (D) is a Gram-positive cocci in clusters, not diplococci.
Another term for spontaneous generation is __________.
- A. biogenesis
- B. abiogenesis
- C. evolution
- D. spontaneity
Correct Answer: B
Rationale: The correct answer is B: abiogenesis. Spontaneous generation refers to the idea that living organisms can arise from non-living matter, which was disproven by Louis Pasteur. Abiogenesis specifically refers to the origin of life from non-living matter, making it synonymous with spontaneous generation. Biogenesis (A) is the principle that living organisms only come from other living organisms. Evolution (C) is the process of gradual change in species over time. Spontaneity (D) refers to happening without external cause and is not directly related to the concept of spontaneous generation.
A patient with pneumonia had a sputum culture revealing Gram-positive diplococci. The bacteria were catalase-negative and alpha-hemolytic. What is the most likely causative agent?
- A. Streptococcus pneumoniae
- B. Staphylococcus aureus
- C. Neisseria meningitidis
- D. Klebsiella pneumoniae
Correct Answer: A
Rationale: Step 1: Gram-positive diplococci suggest a pneumococcal infection.
Step 2: Catalase-negative indicates Streptococcus.
Step 3: Alpha-hemolysis matches S. pneumoniae's characteristics.
Therefore, Streptococcus pneumoniae is the most likely causative agent. Staphylococcus aureus (B) is catalase-positive, Neisseria meningitidis (C) is Gram-negative, and Klebsiella pneumoniae (D) is not diplococci or alpha-hemolytic.
Which of the following bacteria produce toxins that can cause severe gastrointestinal illness?
- A. Vibrio cholerae
- B. Clostridium difficile
- C. Escherichia coli
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D, "All of the above," because all three bacteria listed (Vibrio cholerae, Clostridium difficile, Escherichia coli) produce toxins that can cause severe gastrointestinal illness. Vibrio cholerae produces cholera toxin leading to severe diarrhea. Clostridium difficile produces toxins causing antibiotic-associated diarrhea. Escherichia coli can produce toxins such as Shiga toxin causing severe gastrointestinal symptoms. Therefore, all the options listed are correct in producing toxins that can result in severe gastrointestinal illness.
What measures should be applied to prevent hospital-acquired infections:
- A. Isolation of the source
- B. Isolation of the risk patients
- C. Measures to increase the resistance of the patient to infections
- D. All are correct
Correct Answer: D
Rationale: The correct answer is D because all measures mentioned are important in preventing hospital-acquired infections. Isolating the source helps prevent the spread of infections. Isolating at-risk patients reduces their exposure. Increasing patient resistance to infections through proper hygiene and immunizations minimizes susceptibility. Each measure plays a crucial role in infection prevention, making all options correct.