Nokea
A site of intense B cell proliferation in the lymph node is
- A. Germinal center
- B. Paracortex
- C. Medulla
- D. Infected tissue
Correct Answer: A
Rationale: The correct answer is A: Germinal center. Germinal centers are specialized regions within lymph nodes where B cells undergo intense proliferation, somatic hypermutation, and class switching to generate high-affinity antibodies. This process is crucial for the adaptive immune response. Paracortex (B) contains T cells, not B cells. Medulla (C) is mainly involved in filtering lymph. Infected tissue (D) is not a specific site for B cell proliferation.
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An example of a recombinant vaccine is
- A. DPT (Diphteria/Pertussis/Tetanus)
- B. Hepatitis B
- C. BCG
- D. Measles
Correct Answer: B
Rationale: The correct answer is B: Hepatitis B. Recombinant vaccines are made by inserting genetic material from a pathogen into another organism to stimulate an immune response. Hepatitis B vaccine is produced using recombinant DNA technology to create a non-infectious protein that triggers an immune response against the hepatitis B virus. DPT, BCG, and Measles vaccines are not examples of recombinant vaccines as they are made using different methods without genetic engineering.
How does interferon help the body’s natural defenses?
- A. Directly attacks and destroys virus-infected cells
- B. Augments the immune response by activating phagocytes
- C. Induces production of antiviral proteins in cells that prevent viral replication
- D. Is produced by viral infected cells and prevents the transmission of the virus to adjacent cells
Correct Answer: C
Rationale: Interferons induce the production of antiviral proteins in uninfected cells, preventing viral replication and spread.
Which hypersensitivity type is mediated by T cells?
- A. Type I
- B. Type II
- C. Type III
- D. Type IV
Correct Answer: D
Rationale: The correct answer is D: Type IV hypersensitivity. This type is mediated by T cells, specifically CD4+ helper T cells and CD8+ cytotoxic T cells. The process involves antigen-presenting cells activating T cells, leading to a delayed response. Choices A, B, and C involve different mechanisms and are not mediated by T cells. Type I is mediated by IgE antibodies, Type II involves antibody-mediated cell destruction, and Type III involves immune complex deposition. Therefore, Type IV is the only hypersensitivity type directly mediated by T cells.
When the patient asks about the late effects of chemotherapy and high-dose radiation, what areas of teaching should the nurse plan to include when describing these effects?
- A. Third space syndrome
- B. Secondary malignancies
- C. Chronic nausea and vomiting
- D. Persistent myelosuppression
Correct Answer: B
Rationale: Late effects of chemotherapy and radiation include secondary malignancies due to long-term cellular damage.
NAD and FAD are hydrogen carriers, but cytochromes are electron carriers in bacteria. What happens to the protons (Hâº) in electron transport chains?
- A. They go into solution inside the cytoplasm.
- B. They are taken back by NAD and FAD.
- C. They are carried from cytochromes to oxygen to form water.
- D. They go into solution outside the cytoplasmic membrane.
Correct Answer: D
Rationale: The correct answer is D because in the electron transport chain, protons (H⁺) are pumped across the membrane to create a proton gradient. This gradient is utilized by ATP synthase to produce ATP. Therefore, protons go into solution outside the cytoplasmic membrane. Choices A and B are incorrect because protons do not simply stay in the cytoplasm or get taken back by NAD and FAD. Choice C is incorrect as protons do not directly form water when carried by cytochromes.