Nokea
The rearrangement of gene segments that occurs randomly in B cell receptor genes and T cell receptor genes:
- A. Occurs during clonal expansion of B cells and T cells
- B. Involves rapid genetic mutation after lymphocytes become activated
- C. Allows the mature lymphocyte population to recognize an enormous diversity of antigens
- D. Occurs in the DNA of all cells in the body
Correct Answer: C
Rationale: Step 1: Gene rearrangement in B cell and T cell receptor genes creates unique receptor proteins.
Step 2: This diversity allows mature lymphocytes to recognize a wide range of antigens.
Step 3: This process is crucial for adaptive immune response and antigen specificity.
Step 4: Choices A and B do not accurately describe gene rearrangement.
Step 5: Choice D is incorrect as gene rearrangement is specific to lymphocytes, not all cells in the body.
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Which represents a correct grouping with respect to the target of an immune response, immune response strength, and resulting health status?
- A. Self-antigen, weak response, autoimmune disease
- B. Pathogen, strong response, recurrent infection
- C. Tumour antigen, weak response, cancer
- D. Transplanted organ, strong response, graft acceptance
Correct Answer: C
Rationale: Rationale:
1. Tumor antigens are non-self antigens that trigger a weak immune response due to immune tolerance.
2. Weak immune response against tumor antigens may lead to uncontrolled cell growth, resulting in cancer.
3. Strong immune responses are typically mounted against pathogens to clear infections.
4. Self-antigens should not trigger immune responses to prevent autoimmune diseases.
5. Transplanted organs can elicit strong immune responses leading to rejection, not acceptance.
Summary:
A - Incorrect: Self-antigens should not elicit immune responses to prevent autoimmune diseases.
B - Incorrect: Pathogens typically trigger strong immune responses to clear infections, not recurrent ones.
D - Incorrect: Transplanted organs often lead to strong immune responses and rejection, not acceptance.
The oxidation-reduction pairs X/XHâ‚‚ and Y/YHâ‚‚ have reduction potentials of -50 and +75 millivolts, respectively. This means that electrons would most likely be removed from ______ to reduce ______.
- A. XHâ‚‚, Y
- B. Y, XHâ‚‚
- C. YHâ‚‚, X
- D. Y, YHâ‚‚
Correct Answer: A
Rationale: The correct answer is A: XHâ‚‚, Y. This is because the reduction potential of -50 mV for X/XHâ‚‚ indicates that X is more likely to lose electrons compared to Y with a reduction potential of +75 mV. Therefore, electrons would be removed from XHâ‚‚ (X) to reduce Y. Choice B is incorrect because Y has a higher reduction potential than XHâ‚‚, so electrons would not be removed from Y to reduce XHâ‚‚. Choices C and D are also incorrect as they do not consider the relative reduction potentials of X/XHâ‚‚ and Y/YHâ‚‚.
Determine the following diseases that are not thought to be an autoimmune disease.
- A. Rheumatoid arthritis
- B. Multiple sclerosis
- C. Cancer of the bone marrow
- D. Insulin-dependent diabetes
Correct Answer: C
Rationale: The correct answer is C, Cancer of the bone marrow. Autoimmune diseases occur when the immune system mistakenly attacks healthy cells. Rheumatoid arthritis, multiple sclerosis, and insulin-dependent diabetes are autoimmune diseases where the immune system targets specific tissues or organs. Cancer of the bone marrow, on the other hand, is a result of uncontrolled cell growth and division, not a malfunction of the immune system attacking the body's own tissues. Therefore, it is not considered an autoimmune disease.
Select the correct number of statements that are true.
- A. Only 1 and 3 are correct.
- B. Only 2 and 4 are correct.
- C. Only 3 and 4 are correct.
- D. All of the above are correct.
Correct Answer: A
Rationale: The correct answer is A. Statement 1 and 3 are true because selecting them would result in a correct answer. Statement 2 is incorrect as it claims that only 2 and 4 are correct, which contradicts the correct answer. Statement 4 is also incorrect as it claims that only 3 and 4 are correct, which is not consistent with the correct answer. The option "All of the above are correct" (D) is false because it includes statement 2, which is incorrect. Therefore, A is the correct choice because it accurately identifies the true statements.
Priority Decision: While caring for a patient who is at the nadir of chemotherapy, the nurse establishes the highest priority for nursing actions related to
- A. diarrhea
- B. grieving
- C. risk for infection
- D. inadequate nutritional intake
Correct Answer: C
Rationale: At the nadir, the patient's white blood cell count is lowest, increasing the risk for infection, making it the highest priority.