Nursing Elites

1. What term describes the functional unit of a skeletal muscle responsible for muscle contraction?

• A. Myofibril
• B. Sarcomere
• C. Tendon
• D. Myoglobin

Correct answer: B

Rationale: The correct answer is B, 'Sarcomere.' The sarcomere is indeed the functional unit of a skeletal muscle responsible for muscle contraction. It is composed of actin and myosin filaments that interact to generate muscle contraction. Choice A, 'Myofibril,' is incorrect as myofibrils are composed of sarcomeres, not the functional units themselves. Choice C, 'Tendon,' is incorrect as tendons connect muscles to bones and do not directly participate in muscle contraction. Choice D, 'Myoglobin,' is incorrect as myoglobin is a protein that stores oxygen in muscle cells and is not directly involved in muscle contraction.

2. Which of the following is NOT a recognized mode of natural selection?

• A. Directional selection (favoring one extreme trait value on a spectrum)
• B. Disruptive selection (favoring both extreme trait values on a spectrum)
• C. Stabilizing selection (favoring the average trait value on a spectrum)
• D. Sexual selection (selection based on mate choice that influences reproductive success)

Correct answer: D

Rationale: A) Directional selection is a recognized mode of natural selection where one extreme trait value on a spectrum is favored over others, leading to a shift in the average trait value over time. B) Disruptive selection is a recognized mode of natural selection where both extreme trait values on a spectrum are favored over the average trait value, potentially causing the population to split into distinct groups. C) Stabilizing selection is a recognized mode of natural selection favoring the average trait value on a spectrum over extreme values, resulting in reduced genetic diversity. D) Sexual selection differs from traditional natural selection modes as it involves mate choice and competition for mates, not direct selection pressure on traits affecting survival and reproduction in the environment. Sexual selection can drive the evolution of traits enhancing an individual's attractiveness for mating purposes.

3. What is the role of the diaphragm in respiration?

• A. To regulate air pressure in the lungs
• B. To contract and expand the lungs
• C. To store oxygen
• D. To break down carbon dioxide

Correct answer: B

Rationale: The correct answer is B. The diaphragm plays a crucial role in respiration by contracting and expanding the lungs. When the diaphragm contracts, it moves downward, creating more space in the chest cavity and allowing the lungs to expand. This expansion leads to a decrease in pressure inside the lungs, causing air to rush in. When the diaphragm relaxes, it moves back up, decreasing the space in the chest cavity and causing the lungs to deflate. This action increases the pressure in the lungs, leading to air being pushed out. Therefore, the diaphragm's main function is to facilitate the inhalation and exhalation of air by contracting and expanding the lungs. Choices A, C, and D are incorrect because the diaphragm's primary function is not to regulate air pressure in the lungs, store oxygen, or break down carbon dioxide. Instead, its main purpose is to aid in the mechanical process of breathing.

4. Which element is used in insulin and promotes glucose uptake into cells for energy production?

• A. Zinc
• B. Chromium
• C. Manganese
• D. Iron

Correct answer: B

Rationale: Chromium is the correct answer. Chromium is the element used in insulin that aids in its function by enhancing glucose uptake into cells and regulating blood sugar levels. It plays a crucial role in the body's energy production processes by facilitating the action of insulin. Zinc (Choice A), although important for various physiological functions, is not the element used in insulin. Manganese (Choice C) is necessary for enzyme activation but is not directly involved in insulin's function. Iron (Choice D) is essential for oxygen transport but is not the element used in insulin for promoting glucose uptake into cells.

5. What happens to the kinetic energy of an object when its mass is doubled?

• A. Kinetic energy remains the same
• B. Kinetic energy halves
• C. Kinetic energy doubles
• D. Kinetic energy quadruples

Correct answer: A

Rationale: The correct answer is that the kinetic energy remains the same. Kinetic energy is directly proportional to the mass of an object and the square of its velocity. When the mass is doubled, the kinetic energy would increase if the velocity remains constant. However, in this question, only the mass is mentioned, not the velocity. Therefore, when the mass is doubled, the kinetic energy remains the same as long as the velocity remains constant. Choices B, C, and D are incorrect because they incorrectly suggest changes in kinetic energy that do not accurately reflect the relationship between mass and kinetic energy described in the question.

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