Nokea
TLRs contain a cytoplasmic TIR domain also found in the receptor of
- A. Type I Interferons
- B. IL-1β
- C. TNF-α
- D. IL-8
Correct Answer: B
Rationale: Step-by-step rationale for Choice B (IL-1β) being correct:
1. The TIR domain is present in Toll-like receptors (TLRs) and IL-1 receptor.
2. TLRs recognize various microbial products, while IL-1 receptor binds IL-1 cytokines.
3. Both TLRs and IL-1 receptor signal through the TIR domain.
4. IL-1β is a cytokine that binds to IL-1 receptor, which contains a TIR domain.
Summary of why the other choices are incorrect:
A: Type I Interferons - Type I interferons signal through JAK-STAT pathway, not TIR domain.
C: TNF-α - TNF receptor family signals through TNF receptor-associated death domain, not TIR domain.
D: IL-8 - IL-8 binds to CXCR1 and CXCR2 receptors, which do not contain a TIR domain.
In summary, Choice B
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What discovery is attributed to Elie Metchnikoff?
- A. Antitoxins
- B. Phagocytosis
- C. Germ theory of disease
- D. Smallpox eradication
Correct Answer: B
Rationale: The correct answer is B: Phagocytosis. Elie Metchnikoff is credited with discovering phagocytosis, the process in which certain cells engulf and digest foreign particles or microorganisms. He observed this phenomenon in starfish larvae, leading to a groundbreaking understanding of how immune cells defend the body against pathogens.
Choice A (Antitoxins) is incorrect because although Metchnikoff made contributions to immunology, his notable discovery was phagocytosis, not antitoxins. Choice C (Germ theory of disease) is incorrect as this theory was developed by Louis Pasteur and Robert Koch. Choice D (Smallpox eradication) is incorrect as this achievement is primarily attributed to the efforts of Edward Jenner and the World Health Organization.
What are examples of type I or IgE-mediated hypersensitivity reactions (select all that apply)?
- A. Asthma
- B. Urticaria
- C. Angioedema
- D. Allergic rhinitis
Correct Answer: A
Rationale: Type I hypersensitivity reactions involve IgE-mediated responses, including asthma, urticaria, angioedema, and allergic rhinitis.
What is the normal range for the hematocrit value in a healthy adult?
- A. 20-40%
- B. 40-60%
- C. 60-80%
- D. 80-100%
Correct Answer: B
Rationale: The correct answer is B: 40-60%. Hematocrit represents the percentage of red blood cells in the blood. The normal range for hematocrit in a healthy adult is typically around 40-60%. Values below 40% may indicate anemia, while values above 60% may suggest conditions like dehydration or polycythemia. Choices A, C, and D are incorrect because they fall outside the normal range for hematocrit levels in a healthy adult.
Which of the following complement components mediate inflammation?
- A. C3b
- B. C3a, C4a, and C5a
- C. C5b
- D. C1q
Correct Answer: B
Rationale: The correct answer is B (C3a, C4a, and C5a) because these complement components are known as anaphylatoxins that mediate inflammation by inducing vasodilation, increasing vascular permeability, and recruiting immune cells. C3b (choice A) is involved in opsonization, not inflammation. C5b (choice C) is part of the membrane attack complex for cell lysis. C1q (choice D) initiates the classical complement pathway, but it does not directly mediate inflammation.
What is the primary advantage of the memory function in adaptive immunity?
- A. Rapid and stronger responses to previously encountered antigens
- B. Direct killing of pathogens without prior activation
- C. Enhanced cytokine secretion
- D. Resistance to all infections without exposure
Correct Answer: A
Rationale: The correct answer is A because memory function in adaptive immunity allows for rapid and stronger responses to previously encountered antigens. This is achieved through the presence of memory cells, such as memory B and T cells, which can quickly recognize and respond to specific pathogens upon re-exposure. This leads to a faster and more efficient immune response, providing better protection against future infections.
Choice B is incorrect because direct killing of pathogens without prior activation is a function of innate immunity, not adaptive immunity. Choice C is incorrect as enhanced cytokine secretion is not the primary advantage of memory function. Choice D is incorrect because while memory function provides protection against previously encountered antigens, it does not confer resistance to all infections without exposure.