Nokea
Who accidentally identified the antimicrobial action of penicillin?
- A. Robert Koch
- B. Richard Petri
- C. Alexander Fleming
- D. Louis Pasteur
Correct Answer: C
Rationale: The correct answer is C: Alexander Fleming. Fleming discovered the antimicrobial action of penicillin in 1928 through his experiment with Staphylococcus bacteria. He noticed that mold from a contaminated petri dish inhibited the growth of the bacteria. Robert Koch (A) is known for his work in identifying specific bacteria causing diseases. Richard Petri (B) is not a known figure in the field of microbiology. Louis Pasteur (D) is famous for his germ theory and pasteurization, but he did not discover penicillin's antimicrobial action. Therefore, based on historical evidence and Fleming's specific contribution to microbiology, choice C is the correct answer.
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Which TLR is primarily responsible for recognizing lipopolysaccharide (LPS)?
- A. TLR2
- B. TLR4
- C. TLR5
- D. TLR9
Correct Answer: B
Rationale: The correct answer is B: TLR4. TLR4 is primarily responsible for recognizing lipopolysaccharide (LPS) found in the outer membrane of Gram-negative bacteria. It forms a complex with MD-2 and CD14 to trigger downstream signaling pathways. TLR2 recognizes other microbial components such as lipoproteins. TLR5 recognizes flagellin, a component of bacterial flagella. TLR9 recognizes unmethylated CpG DNA motifs. Therefore, TLR4 is specifically involved in detecting LPS, making it the correct answer in this scenario.
A patient’s documentation indicates he has a stage III pressure ulcer on his right hip. What should the nurse expect to find on assessment of the patient’s right hip?
- A. Exposed bone, tendon, or muscle
- B. An abrasion, blister, or shallow crater
- C. Deep crater through subcutaneous tissue to fascia
- D. Persistent redness (or bluish color in darker skin tones)
Correct Answer: C
Rationale: Stage III pressure ulcers penetrate through all layers of the skin but do not expose underlying structures such as bone or muscle.
What is the lag phase of the primary antibody response?
- A. 1-3 days
- B. 5-10 days
- C. 10-15 days
- D. No lag phase
Correct Answer: B
Rationale: The lag phase of the primary antibody response refers to the time it takes for the immune system to generate specific antibodies after initial exposure to an antigen. The correct answer is B (5-10 days) because during this period, B cells are activated, undergo proliferation, differentiate into plasma cells, and start producing antibodies. This process takes time as the immune system needs to recognize the antigen, mount a response, and produce sufficient antibodies. Option A (1-3 days) is too short for the full activation and differentiation of B cells. Option C (10-15 days) is too long for the typical lag phase duration. Option D (No lag phase) is incorrect because there is always a lag phase before the peak antibody production in the primary immune response.
What is a hallmark of Type IV hypersensitivity?
- A. It is immediate and IgE-mediated
- B. It is delayed and T cell-mediated
- C. It involves immune complexes
- D. It stimulates mast cells to release histamine
Correct Answer: B
Rationale: The correct answer is B because Type IV hypersensitivity reactions are delayed and T cell-mediated. Upon exposure to an antigen, sensitized T cells, specifically CD4+ T cells, release cytokines that recruit and activate macrophages and other effector cells, leading to tissue damage. Choice A is incorrect because Type I hypersensitivity reactions are immediate and IgE-mediated. Choice C is incorrect because immune complex-mediated hypersensitivity reactions are typically associated with Type III hypersensitivity. Choice D is incorrect because histamine release by mast cells is characteristic of Type I hypersensitivity reactions, not Type IV.
Which cell type is a sentinel in the tissues and part of the innate immune system?
- A. T lymphocytes
- B. Dendritic cells
- C. B lymphocytes
- D. Plasma cells
Correct Answer: B
Rationale: The correct answer is B: Dendritic cells. Dendritic cells are sentinel cells in tissues that detect pathogens and activate the immune response. They are crucial in initiating adaptive immune responses by presenting antigens to T cells. T lymphocytes (A) are involved in adaptive immunity, not innate immunity. B lymphocytes (C) mature into plasma cells (D) which produce antibodies, but they are not sentinel cells in tissues like dendritic cells.