Nursing Elites

1. Which region of the small intestine is the primary site of absorption?

• A. Duodenum
• B. Jejunum
• C. Ileum
• D. Cecum

Correct answer: B

Rationale: The jejunum is the correct answer. It is the primary site of nutrient absorption in the small intestine. The duodenum mainly facilitates digestion, the ileum is responsible for further absorption, while the cecum is part of the large intestine and not involved in nutrient absorption.

2. Which vitamin plays a crucial role in calcium absorption in the small intestine?

• A. Vitamin A
• B. Vitamin C
• C. Vitamin D
• D. Vitamin E

Correct answer: C

Rationale: The correct answer is Vitamin D. Vitamin D plays a crucial role in calcium absorption in the small intestine by enhancing the absorption of calcium and phosphorus. This helps in regulating the levels of these minerals in the body, which are essential for maintaining healthy bones. Vitamin A (Choice A) is important for vision and immune function, but it is not directly related to calcium absorption. Vitamin C (Choice B) is primarily known for its role in collagen synthesis and antioxidant functions, not calcium absorption. Vitamin E (Choice D) acts as an antioxidant and is not directly involved in calcium absorption in the small intestine.

3. What is the 'lock-and-key' model?

• A. Protein folding
• B. Enzyme-substrate interaction
• C. Muscle contraction
• D. Blood clotting

Correct answer: B

Rationale: The 'lock-and-key' model describes the specificity of the interaction between enzymes and their substrates. In this model, the enzyme's active site acts like a lock that can only be opened by the specific substrate molecule, which serves as the key. This specific binding ensures that enzymes catalyze particular reactions and do not interact with other molecules indiscriminately. Protein folding (option A) is the process by which a protein attains its functional three-dimensional structure but is not directly related to the lock-and-key model. Muscle contraction (option C) and blood clotting (option D) are complex biological processes but are not directly associated with the lock-and-key model of enzyme-substrate interaction.

4. Which part of the brain is responsible for regulating heart rate, breathing, and swallowing?

• A. Cerebrum
• B. Cerebellum
• C. Medulla oblongata
• D. Thalamus

Correct answer: C

Rationale: The correct answer is C, the medulla oblongata. This part of the brain, located at the base of the brainstem, is primarily responsible for regulating essential functions like heart rate, breathing, and swallowing. Choices A, B, and D are incorrect. The cerebrum is associated with higher brain functions such as thinking and voluntary movements, the cerebellum controls coordination and balance, and the thalamus serves as a relay station for sensory information. Therefore, the medulla oblongata specifically governs the autonomic functions critical for survival.

5. In physics, what does the term 'terminal velocity' refer to?

• A. Maximum velocity reached by an object in free fall
• B. Velocity when the object is at rest
• C. Instantaneous velocity of an object
• D. Velocity only reached by heavy objects

Correct answer: A

Rationale: Terminal velocity in physics refers to the maximum velocity achieved by an object in free fall when the force of gravity equals the force of air resistance. At terminal velocity, the object stops accelerating and maintains a constant speed. This occurs when the opposing forces are balanced, leading to no further increase in speed. Choice B is incorrect as velocity when the object is at rest is zero, not at terminal velocity. Choice C is incorrect as instantaneous velocity refers to the velocity at a specific moment in time, not the maximum speed reached in free fall. Choice D is incorrect because terminal velocity is not exclusive to heavy objects; all objects in free fall can reach terminal velocity under the right conditions.

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