All of the following are true of antigen EXCEPT which one of the following?

Correct Answer: A

Rationale: The correct answer is A. Paratopes are actually parts of antibodies that bind to antigens, not the antigens themselves. A is incorrect because antigens do not contain paratopes; rather, they contain epitopes or antigenic determinants that are recognized by antibodies. B, C, and D are true statements about antigens. B is true because antigens react with antibodies. C is true because antigens contain antigenic determinants that antibodies recognize. D is true because antigens can elicit an immune response by stimulating the production of antibodies. Therefore, the correct answer is A because antigens do not contain paratopes.

Correct Answer: C

Rationale: The correct answer is C: Median nerve. Carpal tunnel syndrome occurs when the median nerve is compressed within the carpal tunnel in the wrist. This compression leads to symptoms like numbness, tingling, and weakness in the hand and fingers. The other choices are incorrect because the radial artery (A) and the brachial artery (B) are blood vessels, not nerves. The ulnar nerve (D) runs along a different path in the arm and is not involved in carpal tunnel syndrome.

Correct Answer: C

Rationale: The correct answer is C: "Skip this week and pick up the schedule next week." Bisphosphonates like alendronate should be taken as directed, typically once weekly. It is important to maintain consistency in dosing to maximize effectiveness and minimize potential side effects. Taking a double dose or taking it late can increase the risk of side effects like gastrointestinal irritation or esophageal damage. Skipping a dose and resuming the schedule next week helps maintain the proper dosing interval. Options A and D suggest taking extra doses, which can be harmful. Option B of taking two doses 3 days apart is also incorrect as it deviates from the prescribed weekly schedule.

Correct Answer: A

Rationale: The correct answer is A: Blood. Naïve T cells are circulating in the blood, ready to encounter antigens. They can move to secondary lymphoid organs like lymph nodes. Germinal centers (B) are sites of B cell maturation, not where naïve T cells are primarily found. While some naïve T cells enter lymph nodes (C), they are not mostly located in the medullary region. Naïve T cells can also migrate to non-lymphoid tissues (D), but their primary residence is in the blood.

Correct Answer: D

Rationale: The correct answer is D because dendritic cells do not typically move rapidly through the germinal center during an immune response. Dendritic cells usually interact with T cells in the paracortex to present antigens, and they are not known to migrate rapidly through the germinal center. A: This statement is correct as T cells do make stable and prolonged contacts with APCs in the paracortex during immune responses. B: This statement is incorrect as B cells do not move at the same speed and randomly in follicles in the absence of antigens. They respond to signals and cues in the microenvironment. C: This statement is correct as specific B cells can quickly direct themselves towards the source of antigen during an infection. In summary, choice D is incorrect because dendritic cells do not move rapidly through the germinal center during an immune response, while the other choices accurately describe behaviors of immune cells during immune responses.