Nokea
The way in which some organism supplies some other organism with food and energy known as
- A. Food chains
- B. Food Network
- C. Pyramid of power
- D. levels of nutrition
Correct Answer: A
Rationale: The correct answer is A: Food chains. A food chain depicts the flow of energy and nutrients from one organism to another in an ecosystem. It shows how energy is transferred from producers to consumers. Food network (B) is a more complex and interconnected system than a simple linear chain. Pyramid of power (C) represents the energy flow in an ecosystem, not the transfer of food. Levels of nutrition (D) is not a term commonly used to describe how organisms transfer food and energy.
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What is the primary characteristic of a secondary immune response?
- A. It is slower and less specific
- B. It is faster, stronger, and more specific
- C. It produces only IgM antibodies
- D. It does not involve memory cells
Correct Answer: B
Rationale: The primary characteristic of a secondary immune response is that it is faster, stronger, and more specific. This is because memory cells generated during the primary response allow for a quicker and more efficient recognition and response to the same antigen upon re-exposure. This results in a faster production of antibodies, a stronger immune response, and increased specificity. Choice A is incorrect as secondary responses are actually faster and more specific. Choice C is incorrect as secondary responses can produce IgG antibodies in addition to IgM. Choice D is incorrect because memory cells are essential for secondary immune responses.
Cells involved in allergic reactions include
- A. Mast cells
- B. Eosinophils
- C. Basophils
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D, "All of the above." Mast cells, eosinophils, and basophils are all involved in allergic reactions. Mast cells release histamine, leading to inflammation. Eosinophils are involved in allergic responses and parasitic infections. Basophils release histamine and other inflammatory mediators. Therefore, all three cell types play a crucial role in allergic reactions. Choices A, B, and C alone are incorrect because each cell type individually participates in allergic reactions.
The nurse is studying hypersensitivity reactions. Which reactions are correctly matched with their hypersensitivity types? (Select one that does not apply.)
- A. Type I—examples include hay fever and anaphylaxis.
- B. Type II—mediated by action of immunoglobulin M (IgM).
- C. Type III—immune complex deposits in blood vessel walls.
- D. Type IV—examples are poison ivy and transplant rejection.
Correct Answer: B
Rationale: The correct answer is B because Type II hypersensitivity reactions are mediated by the action of immunoglobulin G (IgG) or immunoglobulin M (IgM), not just IgM alone. IgG or IgM antibodies target specific antigens on the surface of cells or tissues, leading to cell destruction. In contrast, Type I hypersensitivity reactions (choice A) involve immediate IgE-mediated responses to allergens like hay fever and anaphylaxis. Type III reactions (choice C) are characterized by immune complex deposition in tissues, not blood vessel walls. Type IV reactions (choice D) are delayed hypersensitivity reactions involving T cell-mediated responses, such as poison ivy contact dermatitis and transplant rejection.
Which of the following is a characteristic of CTL?
- A. They kill target cells through recognition of peptide-MHC class I complexes
- B. They die in the process of killing a target cell
- C. They can kill target cells by activating complement
- D. They carry out their effector function in secondary lymphoid tissues
Correct Answer: A
Rationale: The correct answer is A because cytotoxic T lymphocytes (CTLs) kill target cells by recognizing specific peptide antigens presented on major histocompatibility complex (MHC) class I molecules. This recognition triggers the CTLs to release cytotoxic molecules that induce apoptosis in the target cells. Choice B is incorrect because CTLs do not die in the process of killing target cells; they survive to continue their immune response. Choice C is incorrect as CTLs do not kill target cells by activating complement, but rather through direct cell-cell contact. Choice D is incorrect because CTLs carry out their effector function in peripheral tissues where they encounter target cells, not specifically in secondary lymphoid tissues.
Select incorrect mechanism for the development of autoimmune disorder.
- A. A second exposure to an allergen.
- B. Cross-reaction of antibodies formed against foreign antigens with self-antigens.
- C. Exposure of previously 'hidden' self-antigens to the adaptive immune system.
- D. Mutation followed by the appearance of membrane proteins not previously present.
Correct Answer: A
Rationale: The correct answer is A. A second exposure to an allergen does not lead to the development of autoimmune disorders. The key mechanisms involved in autoimmune disorders are self-tolerance breakdown and immune system attacking self-antigens.
Explanation:
1. B: Cross-reaction of antibodies formed against foreign antigens with self-antigens is a possible mechanism for autoimmune disorders.
2. C: Exposure of previously 'hidden' self-antigens to the adaptive immune system can trigger autoimmune responses.
3. D: Mutation followed by the appearance of membrane proteins not previously present can lead to autoimmune disorders, as the immune system may recognize these proteins as foreign.
Summary:
Choice A is incorrect because a second exposure to an allergen does not cause the immune system to target self-antigens, which is the hallmark of autoimmune disorders. Choices B, C, and D are more plausible mechanisms for the development of autoimmune disorders.