Nursing Elites

1. From which type of tissue is the myelin sheath derived, a fatty substance that insulates nerve fibers?

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

Correct answer: C

Rationale: The myelin sheath, a fatty substance that insulates nerve fibers, is derived from nervous tissue, specifically glial cells. Glial cells, including oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system, are responsible for producing the myelin sheath that surrounds and insulates nerve fibers, aiding in the conduction of nerve impulses. Epithelial tissue (Choice A), Muscle tissue (Choice B), and Connective tissue (Choice D) are not responsible for producing the myelin sheath; instead, nervous tissue (glial cells) plays this crucial role.

2. What is the purpose of a catalyst?

• A. To increase a reaction rate by increasing the activation energy
• B. To increase a reaction rate by increasing the temperature
• C. To increase a reaction rate by decreasing the activation energy
• D. To increase a reaction rate by decreasing the temperature

Correct answer: C

Rationale: The purpose of a catalyst is to increase a reaction's rate by decreasing the activation energy required for the reaction to occur. This allows the reaction to proceed more quickly without being consumed in the process. The catalyst provides an alternate mechanism with a lower activation energy, making it easier for the reactants to convert into products. Choice A is incorrect because a catalyst lowers, not increases, the activation energy. Choice B is incorrect because a catalyst does not affect the temperature directly but provides an alternative pathway for the reaction to occur more easily. Choice D is incorrect because a catalyst does not lower the temperature but facilitates the reaction by lowering the activation energy barrier. Therefore, the correct answer is C, 'To increase a reaction rate by decreasing the activation energy.'

3. What is the ultimate end product of glucose breakdown in glycolysis?

• A. ATP
• B. NADPH
• C. Pyruvic acid
• D. Oxygen

Correct answer: C

Rationale: The ultimate end product of glucose breakdown in glycolysis is pyruvic acid. During glycolysis, glucose is broken down into pyruvic acid through a series of enzymatic reactions. ATP is produced as an energy carrier during glycolysis, but it is not the final end product. NADPH is not a direct product of glycolysis; it is mainly produced in the pentose phosphate pathway. Oxygen is not a product of glycolysis but is used as an electron acceptor in the electron transport chain of cellular respiration.

4. What determines the frequency of oscillations in a spring-mass system when the spring is stretched and released?

• A. The mass of the object
• B. The stiffness of the spring
• C. The initial displacement of the object
• D. All of the above

Correct answer: B

Rationale: The frequency of oscillations in a spring-mass system is determined by the stiffness of the spring (spring constant) and the mass of the object. The stiffness of the spring affects how quickly the system oscillates back and forth, while the mass of the object influences the inertia and therefore the frequency. The initial displacement of the object does not impact the frequency of oscillations. Choice A is incorrect because while the mass of the object affects the frequency, it is not the sole determining factor. Choice C is incorrect as the initial displacement affects the amplitude of oscillations, not the frequency. Choice D is incorrect as not all factors listed determine the frequency, making it an incorrect choice.

5. A scientist wants to measure how far a person can run in 30 minutes. Which of the following units should be used to record this measurement as a small number?

• A. Gigameters
• B. Kilometers
• C. Megameters
• D. Terameters

Correct answer: B

Rationale: Kilometers are commonly used for shorter distances and would provide a small and practical number to measure distance in this context. Gigameters, Megameters, and Terameters are much larger units of measurement and would result in very large numbers, making them impractical for measuring the distance a person can run in 30 minutes. Therefore, the correct choice is Kilometers as it is a suitable unit for measuring such distances within a reasonable range.

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