Nursing Elites

1. Most catalysts found in biological systems are which of the following?

• A. Special lipids called cofactors.
• B. Special proteins called enzymes.
• C. Special lipids called enzymes.
• D. Special proteins called cofactors.

Correct answer: B

Rationale: Enzymes are special proteins that act as catalysts in biological systems. They accelerate chemical reactions by lowering the activation energy required for the reaction to occur. Enzymes play a critical role in the regulation of metabolic pathways and are essential for various biological processes. While some enzymes may require cofactors for activity, the enzymes themselves are the catalysts in biological systems. Therefore, choice B, special proteins called enzymes, is the most suitable answer. Choices A, C, and D are incorrect because enzymes, not lipids, are the primary catalysts in biological systems.

2. What is the protective fluid surrounding the brain and spinal cord called?

• A. Blood
• B. Cerebrospinal fluid
• C. Plasma
• D. Myelin

Correct answer: B

Rationale: Cerebrospinal fluid is the protective fluid that surrounds the brain and spinal cord. It acts as a cushion to protect these vital organs from injury and provides nutrients to the nervous system. Blood, plasma, and myelin are not the fluids specifically surrounding the brain and spinal cord. Blood is found within blood vessels, plasma is the liquid component of blood, and myelin is a fatty substance that forms a protective sheath around nerve fibers.

3. Which hormone, produced by the ovaries, is responsible for the development of the uterine lining during the menstrual cycle and supports early pregnancy?

• A. Estrogen
• B. Progesterone
• C. Testosterone
• D. Prolactin

Correct answer: B

Rationale: Progesterone, produced by the ovaries, is responsible for the development of the uterine lining during the menstrual cycle and supports early pregnancy. While estrogen also plays a crucial role in the menstrual cycle, progesterone is specifically known for its role in preparing the uterus for pregnancy and maintaining the uterine lining. Testosterone is primarily a male sex hormone and not directly involved in these processes. Prolactin is a hormone that is mainly associated with milk production and not related to the development of the uterine lining or early pregnancy.

4. What is the neural pathway that triggers a reflex action?

• A. Reflex loop
• B. Reflex arc
• C. Neural pathway
• D. Reflex reaction

Correct answer: B

Rationale: The correct answer is 'B: Reflex arc.' A reflex arc is the neural pathway that triggers an automatic, involuntary reflex action in response to a stimulus. It involves sensory neurons, interneurons in the spinal cord, and motor neurons, allowing for a rapid response without conscious thought. Choice A, 'Reflex loop,' is incorrect as the term commonly used is 'Reflex arc' to describe this neural pathway. Choice C, 'Neural pathway,' is too general and does not specifically refer to the pathway involved in reflex actions. Choice D, 'Reflex reaction,' is not the commonly accepted term to describe the neural pathway that triggers reflex actions.

5. The average life expectancy at birth in the United States at the beginning of the 21st century was about 75 years. The average life expectancy at birth in the middle of the 19th century was only about 40 years. Which of the following factors are likely to have contributed to the longer life expectancy in the 21st century? (Select the one that does not apply)

• A. The human body has evolved to become more resilient to its environment.
• B. There have been numerous advances in medical technology and treatments.
• C. Higher standards of basic cleanliness have helped people avoid illness.
• D. The creation of vaccines has nearly eliminated certain diseases that were once deadly.

Correct answer: A

Rationale: Medical advances, higher standards of cleanliness, and the creation of vaccines have all significantly contributed to the increase in life expectancy over time. While human evolution plays a role in adaptation to the environment over millennia, it is not a primary factor that has led to the substantial increase in life expectancy within a few centuries. The human body's evolution is a slow process that occurs over generations, while the advancements in medical technology, cleanliness, and vaccines have had a more immediate and direct impact on improving life expectancy.

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