Nursing Elites

1. What is the primary function of platelets in the blood?

• A. To carry oxygen
• B. To clot blood
• C. To fight infection
• D. To transport nutrients

Correct answer: B

Rationale: The correct answer is B: 'To clot blood.' Platelets play a crucial role in the clotting process, forming a plug at the site of blood vessel injury to prevent excessive bleeding. While red blood cells carry oxygen, white blood cells fight infection, and nutrients are transported by plasma, platelets are specifically responsible for blood clotting. Choice A is incorrect because red blood cells are responsible for carrying oxygen. Choice C is incorrect because white blood cells are primarily involved in fighting infection. Choice D is incorrect as the transport of nutrients is mainly carried out by plasma, not platelets.

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 compound is a component of baking soda and is important for maintaining pH balance in the body?

• A. Potassium
• B. Sodium
• C. Calcium
• D. Sodium bicarbonate

Correct answer: D

Rationale: The correct answer is D, Sodium bicarbonate. Sodium bicarbonate, commonly known as baking soda, is a compound that plays a crucial role in maintaining pH balance in the body. When ingested, sodium bicarbonate acts as a buffer, helping to regulate the body's pH levels. It is essential for various physiological functions. Choices A, B, and C are incorrect. Potassium, calcium, and sodium are important minerals in the body but are not components of baking soda or directly responsible for maintaining pH balance in the same way as sodium bicarbonate.

4. What is the rigid structure that provides shape and support to plant cells?

• A. Cell wall
• B. Plasma membrane
• C. Nucleus
• D. Cytoplasm

Correct answer: A

Rationale: The correct answer is the cell wall, as it is the rigid structure that provides shape and support to plant cells. The cell wall is located outside the plasma membrane and is primarily composed of cellulose, giving it its rigid nature. The plasma membrane (option B) is a semi-permeable membrane surrounding the cell that regulates the movement of substances in and out of the cell. The nucleus (option C) houses the cell's genetic material and controls cellular activities. Cytoplasm (option D) is the gel-like substance within the cell that surrounds organelles and where various cellular processes take place, but it does not provide the rigid structure and support that the cell wall does.

5. When a muscle shortens and generates force, this is called a:

• A. Contraction
• B. Relaxation
• C. Extension
• D. Atrophy

Correct answer: A

Rationale: When a muscle shortens and generates force, it is contracting. Contraction is the process by which muscle fibers develop tension and exert a pulling force on the bones they are attached to, resulting in movement. Relaxation refers to the phase when a muscle returns to its original length, allowing for rest or preparation for the next contraction. Extension, on the other hand, is the movement that increases the angle between body parts, moving them further apart. Atrophy is unrelated to muscle contraction and refers to the wasting away or decrease in size of muscle tissue due to disuse or disease. Therefore, the correct answer is 'Contraction.'

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