Nokea
T cell receptor and B cell receptor genes both undergo:
- A. Somatic hypermutation
- B. Germline gene rearrangement
- C. Isotype switching
- D. Both A and B are correct
Correct Answer: B
Rationale: The correct answer is B, germline gene rearrangement. T cell receptor and B cell receptor genes both undergo germline gene rearrangement during lymphocyte development, where gene segments are rearranged to generate diverse antigen receptor specificities. Somatic hypermutation and isotype switching are processes specific to B cells in the adaptive immune response, not T cells. Therefore, choices A and C are incorrect. Choice D is incorrect as well since somatic hypermutation is not a process involved in T cell receptor gene rearrangement.
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The annotation D refers to which DNA component?
- A. Plasmid DNA
- B. Vector DNA
- C. Insert DNA
- D. Recombinant DNA
Correct Answer: D
Rationale: The correct answer is D: Recombinant DNA. Recombinant DNA refers to the DNA molecule formed by combining DNA from different sources. In genetic engineering, this is created by inserting a foreign DNA fragment into a vector DNA, resulting in a new DNA molecule. Plasmid DNA (A) is a small, circular DNA found in bacteria. Vector DNA (B) is a carrier molecule used to transport foreign DNA into a host cell. Insert DNA (C) is the DNA fragment that is inserted into a vector. Therefore, choice D is the correct answer as it specifically refers to the combined DNA molecule formed in genetic engineering.
What dietary advice should the nurse give to clients with HIV/AIDS?
- A. Encourage intake of fat-soluble vitamins in amounts two to five times the RDA
- B. Encourage intake of water-soluble vitamins in amounts two to five times the RDA
- C. Increase the intake of iron and zinc
- D. Decrease the intake of trace element and antioxidant supplements
Correct Answer: B
Rationale: Water-soluble vitamins are crucial for immune function and are often depleted in HIV/AIDS patients so increasing their intake is beneficial.
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 consequence of granzyme entering a target cell?
- A. Neutralization of toxins
- B. Activation of apoptosis pathways
- C. Inhibition of cytokine secretion
- D. Promotion of antigen presentation
Correct Answer: B
Rationale: Granzyme entering a target cell activates apoptosis pathways by inducing cell death. Firstly, granzyme activates caspases leading to cell death. Secondly, it triggers DNA fragmentation and cell shrinkage. Lastly, it enhances membrane blebbing and apoptotic body formation. The other choices are incorrect because granzyme does not neutralize toxins, inhibit cytokine secretion, or promote antigen presentation within a target cell.
A critical role of secondary lymphoid tissues is to:
- A. Provide a place for B and T lymphocytes to mature and begin expression of antigen receptors
- B. Allow co-localization of the components required to activate naïve lymphocytes
- C. Minimize contact of naïve lymphocytes with self antigens
- D. All of the above
Correct Answer: B
Rationale: Step 1: Secondary lymphoid tissues bring together antigen-presenting cells and lymphocytes, facilitating the activation of naïve lymphocytes.
Step 2: Co-localization of these components is essential for efficient immune response initiation.
Step 3: Maturation and expression of antigen receptors primarily occur in primary lymphoid tissues, not secondary.
Summary:
A: Incorrect. Maturation of lymphocytes occurs mainly in primary lymphoid tissues.
C: Incorrect. Contact with self-antigens is necessary for self-tolerance and occurs in primary lymphoid tissues.
D: Incorrect. Only choice B accurately describes the critical role of secondary lymphoid tissues.