Nursing Elites

1. The energy released in nuclear fusion originates from:

• A. The fission of heavy nuclei
• B. The binding energy released during the fusion of light nuclei
• C. Electronic transitions within atoms
• D. Matter-antimatter annihilation

Correct answer: B

Rationale: The correct answer is B: 'The binding energy released during the fusion of light nuclei.' Nuclear fusion is the process where light nuclei combine to form a heavier nucleus, releasing energy in the form of binding energy. This energy comes from the conversion of mass into energy as per Einstein's famous equation E=mc^2. In contrast, option A refers to nuclear fission, where heavy nuclei split into lighter nuclei, releasing energy. Option C is related to atomic energy levels, and option D involves the complete conversion of matter into energy, not specific to nuclear fusion. Therefore, the energy released in nuclear fusion originates from the binding energy released during the fusion of light nuclei.

2. Negative feedback mechanisms are crucial in the endocrine system to:

• A. Increase hormone production continuously
• B. Maintain hormone levels within a specific range
• C. Cause a constant release of hormones
• D. Disrupt communication between glands

Correct answer: B

Rationale: The correct answer is B: 'Maintain hormone levels within a specific range.' Negative feedback mechanisms in the endocrine system are essential for regulating hormone levels. These mechanisms work to counteract any deviations from the set point, ensuring that hormone levels remain balanced and within the optimal range for proper physiological function. Continuous hormone production (A) or constant release of hormones (C) would lead to imbalances and potential harm to the body. Disrupting communication between glands (D) would hinder the coordination necessary for maintaining homeostasis. Therefore, option B is the best choice as it highlights the critical role of negative feedback in keeping hormone levels stable and regulated.

3. A satellite orbits the Earth at constant speed. Which force is responsible for its circular motion?

• A. Gravitational force from the Earth
• B. Thrust from the satellite's engine
• C. Friction between the satellite and the atmosphere
• D. Normal force from the Earth's surface

Correct answer: A

Rationale: This force acts towards the Earth's center, providing the centripetal force required for the satellite to move in a circle.

4. An Egyptian model pyramid has a square base side length of 10cm and a height of 8cm. What is its volume?

• A. 20 cu cm
• B. 40 cu cm
• C. 80 cu cm
• D. 160 cu cm

Correct answer: D

Rationale: Use the formula for volume of a pyramid: (1/3) * base area * height. Calculate the base area (10cm * 10cm = 100 sq cm) and substitute: (1/3) * 100 sq cm * 8cm = 80 cu cm.

5. Myelin sheath, a fatty substance, insulates nerve fibers. What type of tissue is the myelin sheath derived from?

• A. Epithelial tissue
• B. Muscle tissue
• C. Nervous tissue (glial cells)
• D. Connective tissue

Correct answer: C

Rationale: The myelin sheath is derived from nervous tissue, specifically from glial cells, which are non-neuronal cells that support and protect neurons in the nervous system. Glial cells, such as Schwann cells in the peripheral nervous system and oligodendrocytes in the central nervous system, produce the myelin sheath to insulate nerve fibers and enhance the speed of nerve impulse conduction. Epithelial tissue forms the protective covering of internal and external surfaces, muscle tissue is responsible for movement, and connective tissue provides support and structure to the body. Therefore, the correct answer is C: Nervous tissue (glial cells).

6. Which of the following describes the difference between prokaryotic and eukaryotic cells?

• A. Prokaryotic cells have a nucleus, while eukaryotic cells don't.
• B. Eukaryotic cells are simpler in structure than prokaryotic cells.
• C. Prokaryotic cells have membrane-bound organelles, while eukaryotic cells don't.
• D. Eukaryotic cells have a true nucleus and membrane-bound organelles, while prokaryotic cells lack these.

Correct answer: A

Rationale: The correct answer is A: 'Prokaryotic cells have a nucleus, while eukaryotic cells don't.' Prokaryotic cells lack a membrane-bound nucleus and other membrane-bound organelles, while eukaryotic cells have a true nucleus enclosed within a nuclear membrane. This distinction is a fundamental difference between the two cell types. Choice B is incorrect because eukaryotic cells are actually more complex than prokaryotic cells due to their membrane-bound organelles. Choice C is incorrect because prokaryotic cells lack membrane-bound organelles. Choice D is incorrect because eukaryotic cells have both a true nucleus and membrane-bound organelles, unlike prokaryotic cells. Understanding this key difference is crucial in understanding the diversity of cell types in living organisms.

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