Nursing Elites

1. How do spindle fiber dynamics and microtubule attachment regulate cell cycle checkpoints?

• A. Misaligned chromosomes fail to attach to microtubules, triggering a delay in anaphase onset.
• B. The presence of unattached kinetochores on the centromeres sends a signal to pause cell cycle progression.
• C. Microtubule instability and rapid depolymerization lead to the activation of checkpoint proteins.
• D. All of the above.

Correct answer: D

Rationale: A) Misaligned chromosomes fail to attach to microtubules, triggering a delay in anaphase onset: Proper attachment of chromosomes to spindle fibers is essential for accurate segregation of genetic material during cell division. Misaligned chromosomes that fail to attach to microtubules can lead to delays in anaphase onset, allowing the cell to correct errors before proceeding with division. B) The presence of unattached kinetochores on the centromeres sends a signal to pause cell cycle progression: Kinetochores at the centromeres help attach chromosomes to spindle fibers. When kinetochores are unattached or improperly attached to microtubules, they signal the cell to pause cell cycle progression, ensuring proper chromosome alignment before division. C) Microtubule instability and rapid depolymerization lead to the activation of checkpoint proteins: While microtubule dynamics are crucial for cell division, microtubule instability and rapid depolymerization can disrupt chromosome attachment. However, this mechanism is not directly related to the activation of cell cycle checkpoint proteins, making this statement incorrect. Therefore, choices A and B accurately describe how spindle fiber dynamics and microtubule attachment regulate cell cycle checkpoints, making option D the correct answer.

2. What does the T wave on an ECG correspond to?

• A. Atrial depolarization
• B. Ventricular depolarization
• C. Atrial repolarization
• D. Ventricular repolarization

Correct answer: D

Rationale: The T wave on an ECG corresponds to ventricular repolarization. Following ventricular depolarization, which is represented by the QRS complex, the ventricles undergo repolarization during the T wave. This phase signifies the recovery of ventricular muscle cells as they prepare for the subsequent depolarization cycle. Choices A, B, and C are incorrect because the T wave specifically reflects the repolarization of the ventricles, not the atria or their respective depolarization or repolarization phases.

3. Which of the following is the y-intercept of the line whose equation is 7y − 42x + 7 = 0?

• A. (1/6, 0)
• B. (6, 0)
• C. (0, −1)
• D. (−1, 0)

Correct answer: C

Rationale: To find the y-intercept, set x = 0 in the equation 7y − 42x + 7 = 0. This simplifies to 7y - 42(0) + 7 = 0, which gives 7y = -7. Solving for y, we get y = -1. Therefore, the y-intercept is where x = 0, so the correct answer is (0, -1). Choice A (1/6, 0) is incorrect as it does not satisfy the given equation when x = 0. Choice B (6, 0) is incorrect as it represents the x-intercept. Choice D (-1, 0) is incorrect as it does not correspond to the y-intercept of the given equation.

4. What is the main function of white blood cells?

• A. Transport oxygen
• B. Fight infection
• C. Produce antibodies
• D. Regulate body temperature

Correct answer: B

Rationale: The main function of white blood cells is to fight infection, making choice B the correct answer. White blood cells are a crucial component of the immune system, working to defend the body against pathogens and foreign invaders. Choices A, C, and D are incorrect because white blood cells do not primarily transport oxygen, produce antibodies, or regulate body temperature. While some blood cells are involved in these functions, the primary role of white blood cells is to combat infections and maintain the body's immune response.

5. What is the median of Pernell's scores (81, 92, 87, 89, and 94)?

• A. 87
• B. 89
• C. 92
• D. 94

Correct answer: B

Rationale: To find the median, we first need to arrange the scores in ascending order: 81, 87, 89, 92, 94. Since there are five scores, the middle score would be the third one, which is 89. Hence, the median of Pernell's scores is 89. Choice A (87) is incorrect because it is the second score in the ordered list, not the middle one. Choice C (92) and Choice D (94) are also incorrect as they are not positioned in the middle of the ordered series.

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