Nursing Elites

1. Which of the following scenarios represents an example of static friction?

• A. Sliding a heavy box across the floor
• B. A car moving around a curve
• C. Pushing a stationary object
• D. Braking a car to stop

Correct answer: C

Rationale: The correct answer is C. Static friction occurs when two surfaces are in contact but not moving relative to each other. Pushing a stationary object involves static friction as you apply a force to overcome the friction keeping the object stationary. Choices A, B, and D involve kinetic friction, which occurs when two surfaces are moving relative to each other. Option A involves moving the box across the floor, which is an example of kinetic friction. Option B involves the movement of a car around a curve, which also relates to kinetic friction due to the relative movement between the tires and the road. Option D describes braking a car to stop, where the moving car's wheels interact with the road, creating kinetic friction to slow down and stop the car.

2. 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.

3. Which part of the nervous system controls the 'fight or flight' response?

• A. Central nervous system
• B. Peripheral nervous system
• C. Autonomic nervous system
• D. Sympathetic nervous system

Correct answer: D

Rationale: The correct answer is the sympathetic nervous system. It controls the 'fight or flight' response by preparing the body for stressful situations. The central nervous system (Choice A) consists of the brain and spinal cord but does not directly control the 'fight or flight' response. The peripheral nervous system (Choice B) includes nerves outside the brain and spinal cord, while the autonomic nervous system (Choice C) regulates involuntary bodily functions but is not specific to the 'fight or flight' response.

4. During normal breathing, which muscle is the primary driver of inhalation by contracting and flattening to increase the volume of the thoracic cavity?

• A. Diaphragm
• B. Intercostal muscles
• C. Abdominal muscles
• D. Pectoral muscles

Correct answer: A

Rationale: The diaphragm is the primary muscle responsible for inhalation during normal breathing. When it contracts, it flattens, increasing the volume of the thoracic cavity and creating a negative pressure that allows air to flow into the lungs. Intercostal muscles also play a role in expanding the chest cavity during inhalation, but the diaphragm is the main driver of the process. Abdominal muscles are primarily involved in exhalation by pushing the diaphragm upward to expel air from the lungs. Pectoral muscles are involved in movements of the arms and shoulders, not in breathing, making them incorrect choices for this question.

5. Which skin condition is characterized by patches of inflamed, reddened skin and is often triggered by allergens or stress?

• A. Eczema
• B. Psoriasis
• C. Acne
• D. Vitiligo

Correct answer: A

Rationale: Eczema is the correct answer. It presents as patches of inflamed, reddened skin and can be triggered by allergens, stress, or other factors. Psoriasis, on the other hand, is characterized by red, scaly patches rather than inflamed and reddened skin. Acne manifests as pimples and blemishes, not patches of inflamed skin. Vitiligo is characterized by the loss of skin color in patches, which is distinct from the symptoms described in the question.

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