Nokea
The term 'lymphocyte repertoire' refers to:
- A. The range of antigen receptor specificities found in a lymphocyte population
- B. The variety of effector functions that result from an adaptive immune response
- C. Antigen receptor specificities found on a given lymphocyte
- D. The collection of daughter cells produced when a lymphocyte divides after activation
Correct Answer: A
Rationale: The correct answer is A because the term 'lymphocyte repertoire' specifically refers to the range of antigen receptor specificities found in a lymphocyte population. Lymphocytes are immune cells that play a crucial role in recognizing and responding to antigens, and their diverse antigen receptor specificities allow them to recognize a wide range of pathogens. This term does not refer to effector functions (B) or a single lymphocyte's receptor specificities (C). Additionally, it does not describe the collection of daughter cells produced after division (D), as the repertoire refers to the initial diversity of antigen receptors within a lymphocyte population.
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Priority Decision: On assessment of a central venous access device (CVAD) site, the nurse observes that the transparent dressing is loose along two sides. What should the nurse do immediately?
- A. Wait and change the dressing when it is due
- B. Tape the two loose sides down and document
- C. Apply a gauze dressing over the transparent dressing and tape securely
- D. Remove the dressing and apply a new transparent dressing using sterile technique
Correct Answer: D
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The physician plans to prescribe trastuzumab (Herceptin) for the patient with breast cancer. What testing will the physician order before prescribing this medication?
- A. HER2 protein levels
- B. BRCA2 gene mutation
- C. BRCA1 gene mutation
- D. Stage II cancer identification
Correct Answer: A
Rationale: Trastuzumab targets HER2-positive breast cancers, so HER2 protein level testing is essential to determine eligibility.
Neurons are
- A. Cells specialized for carrying signals
- B. The functional units of the nervous system
- C. consists of A cell body, Dendrites and Axons
- D. all above
Correct Answer: D
Rationale: The correct answer is D because neurons are specialized cells that carry signals, making them the functional units of the nervous system. Neurons consist of a cell body, dendrites, and axons, fulfilling the criteria mentioned in options A, B, and C. Therefore, option D encompasses all the essential characteristics of neurons, making it the correct choice. Options A, B, and C individually do not fully capture the comprehensive nature of neurons, as they only cover specific aspects of what neurons are, whereas option D encompasses all the correct statements regarding neurons.
The Calvin cycle:
- A. is a C5 pathway
- B. is used by all photoautotrophic microorganisms
- C. is a C4 pathway
- D. is a dark reaction
Correct Answer: D
Rationale: The Calvin cycle is a series of biochemical reactions that take place in the stroma of chloroplasts during photosynthesis. It occurs in the dark phase (without direct light requirement), making choice D correct. Choice A is incorrect because the Calvin cycle is a C3 pathway, not C5. Choice B is incorrect because not all photoautotrophic microorganisms use the Calvin cycle; some use alternative pathways. Choice C is incorrect because C4 pathway is a different photosynthetic pathway that occurs in certain plants to minimize photorespiration.
What is the process called when a specific lymphocyte binds its antigen and proliferates?
- A. Clonal deletion
- B. Clonal selection
- C. Antigen presentation
- D. Cytokine signaling
Correct Answer: B
Rationale: The correct answer is B: Clonal selection. During clonal selection, a specific lymphocyte recognizes its specific antigen, binds to it, and undergoes proliferation to generate a large population of identical cells to combat the antigen efficiently. This process ensures an effective immune response.
Incorrect choices:
A: Clonal deletion - This process involves the elimination of self-reactive lymphocytes to prevent autoimmunity, not the proliferation of antigen-specific lymphocytes.
C: Antigen presentation - This is the process by which antigens are displayed to immune cells for recognition, not the proliferation of lymphocytes.
D: Cytokine signaling - While cytokines play a role in immune responses, they are not directly involved in the proliferation of lymphocytes in response to specific antigens.