What is the role of innate immunity in relation to adaptive immunity?

Correct Answer: B

Rationale: The correct answer is B because innate immunity instructs and activates adaptive immunity. Innate immunity serves as the first line of defense against pathogens, recognizing and initiating a response to pathogens. It then communicates with adaptive immunity, providing signals and antigens to activate and guide the adaptive immune response. This collaboration is crucial for the effective elimination of pathogens. Choices A, C, and D are incorrect because innate immunity does not suppress, replace, or function independently of adaptive immunity; rather, they work together in a coordinated manner to provide a comprehensive immune response.

Correct Answer: C

Rationale: The correct answer is C: Recruitment and activation of immune cells. C5a is a potent chemoattractant that attracts immune cells to the site of infection or inflammation. It also activates these immune cells, leading to enhanced immune responses. Option A (Opsonization) and B (Cell lysis) are not the main functions of C5a. Option D (Inhibition of inflammation) is incorrect because C5a actually promotes inflammation by recruiting and activating immune cells.

Correct Answer: B

Rationale: The correct answer is B because cytokines act as signaling molecules to coordinate immune responses in innate immunity. They help regulate inflammation, activate immune cells, and promote clearance of pathogens. Option A is incorrect because cytokines do not directly kill pathogens. Option C is incorrect as cytokines play a crucial role in both innate and adaptive immunity. Option D is incorrect because cytokines do not inhibit phagocytosis; instead, they enhance this process to help eliminate pathogens.

Correct Answer: B

Rationale: The correct answer is B because Toll-like receptors (TLRs) recognize common molecular patterns shared by groups of microbes, allowing for rapid detection of a wide range of pathogens. This recognition triggers immune responses without the need for prior exposure to the specific pathogen. The other choices are incorrect because: A: TLRs are not highly specific to individual pathogens but rather recognize common patterns. C: TLRs do not directly activate B cell antibody production; they initiate immune responses by activating various immune cells. D: TLRs do not require antigen presentation to function; they directly recognize microbial patterns.

Correct Answer: B

Rationale: The three main principles of adaptive immunity are Recognize, Respond, Remember. 1. Recognize: Immune system identifies specific pathogens through antigen recognition. 2. Respond: Immune response is triggered to eliminate the pathogen. 3. Remember: Immune system forms memory cells for faster and stronger response upon re-exposure. Other options are incorrect: A: Respond, Replace, Repair - Incorrect as it does not reflect the key processes of adaptive immunity. C: Resist, Retain, Recruit - Incorrect as these terms do not accurately describe the adaptive immune response. D: React, Replicate, Restore - Incorrect as it does not encompass the essential principles of adaptive immunity.