Nursing Elites

1. Which of the following is an example of a polymer?

• A. Methane
• B. Ethanol
• C. Polyethylene
• D. Acetic acid

Correct answer: C

Rationale: The correct answer is C, Polyethylene. Polyethylene is a polymer composed of a large number of repeating ethylene units linked together, forming a long-chain molecule, characteristic of polymers. Methane, ethanol, and acetic acid are small organic molecules that do not demonstrate the repeating unit structure typical of polymers. Therefore, they are not examples of polymers.

2. Which feedback loops are less common and sometimes harmful because they enhance stimuli rather than inhibit them?

• A. Negative feedback loop
• B. Positive feedback loop
• C. Inhibitory feedback loop
• D. Stimulating feedback loop

Correct answer: B

Rationale: Correct. Positive feedback loops enhance or amplify changes, which can sometimes be harmful as they drive processes further from equilibrium. In contrast, negative feedback loops work to counteract deviations from a set point, promoting stability. Choice A, 'Negative feedback loop,' is incorrect because negative feedback loops inhibit or reduce changes, promoting stability. Choice C, 'Inhibitory feedback loop,' is incorrect as it is synonymous with negative feedback loops. Choice D, 'Stimulating feedback loop,' is incorrect as it inaccurately describes the nature of positive feedback loops.

3. How does the Law of Conservation of Mass apply to this reaction: 2H₂ + O₂ → 2H₂O?

• A. Electrons are not lost.
• B. The hydrogen does not lose mass.
• C. New water molecules are formed.
• D. There is no decrease or increase in matter.

Correct answer: D

Rationale: The Law of Conservation of Mass states that matter cannot be created or destroyed in a chemical reaction. In the given reaction, 2 moles of hydrogen combine with 1 mole of oxygen to form 2 moles of water. The total mass of the reactants (hydrogen and oxygen) is equal to the total mass of the products (water), meaning there is no decrease or increase in matter. The total mass of the system remains constant, demonstrating the conservation of mass. Choices A, B, and C are incorrect because the conservation of mass does not specifically relate to electrons, individual elements (like hydrogen), or the formation of new molecules; instead, it focuses on the overall mass of the system before and after the reaction.

4. Which of the following hormones is produced by the adrenal medulla and prepares the body for a stressful situation?

• A. Testosterone
• B. Cortisol
• C. Epinephrine (adrenaline)
• D. Growth hormone

Correct answer: C

Rationale: The correct answer is C: Epinephrine (adrenaline). Epinephrine is produced by the adrenal medulla and is responsible for preparing the body for a stressful situation. It increases heart rate, dilates airways, and mobilizes energy stores to help the body respond to a fight-or-flight scenario. Testosterone (Choice A) is a sex hormone produced by the testes in males and in smaller amounts by the ovaries in females, not by the adrenal medulla. Cortisol (Choice B) is a stress hormone produced by the adrenal cortex, not the adrenal medulla. Growth hormone (Choice D) is produced by the pituitary gland and is involved in growth, metabolism, and various bodily functions, not by the adrenal medulla.

5. Glial cells support and protect neurons within the central and peripheral nervous system. What are they called?

• A. Astrocytes
• B. Neuroglia
• C. Oligodendrocytes
• D. Schwann cells

Correct answer: A

Rationale: Astrocytes are a type of glial cell that provide support and protection for neurons in both the central and peripheral nervous systems. While the term 'Neuroglia' is often used to refer to glial cells collectively, in this context, the question specifically asks for the name of the cells, making 'Astrocytes' the correct answer. Choice B, 'Neuroglia,' is a general term for all glial cells, not a specific type. Choices C and D, 'Oligodendrocytes' and 'Schwann cells,' are also types of glial cells but are not the primary cells responsible for supporting and protecting neurons as described in the question.

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