Nursing Elites

1. The involuntary, rhythmic contractions of the heart muscle are controlled by a specialized group of cells located in the:

• A. Lungs
• B. Brain
• C. Spinal cord
• D. Sinoatrial node (located within the heart)

Correct answer: D

Rationale: The correct answer is D: Sinoatrial node (located within the heart). The sinoatrial node, also known as the heart's natural pacemaker, is a cluster of specialized cells within the heart that controls the heart rate by initiating the electrical impulses that regulate the heart's contractions. The lungs (A), brain (B), and spinal cord (C) do not directly control the rhythmic contractions of the heart muscle. Therefore, the sinoatrial node is the specific anatomical location responsible for regulating the heart's rhythmic contractions, making it the correct answer.

2. What is the best way to revise the sentence: "Her eyes glistened with tears in the moonlight"?

• A. Her eyes glistened in the moonlight, with tears.
• B. Tears glistened in her eyes with moonlight.
• C. Her eyes, in the moonlight, glistened with tears.
• D. Tears made her eyes glisten in the moonlight.

Correct answer: C

Rationale: Option C rearranges the elements for smoother flow and emphasis on the tears.

3. What is the process by which lighter nuclei fuse to form heavier nuclei, releasing a large amount of energy?

• A. Fission
• B. Fusion
• C. Radioactivity
• D. Chain reaction

Correct answer: B

Rationale: Fusion is the process by which lighter nuclei combine to form heavier nuclei, releasing a large amount of energy in the process. This process is the source of energy in stars, including our Sun, and is different from fission, which involves the splitting of heavier nuclei into lighter nuclei. Radioactivity refers to the emission of particles or radiation from the nucleus of an unstable atom, while a chain reaction is a self-sustaining reaction where the products of one reaction cause further reactions.

4. Which nitrogenous bases pair with each other in DNA?

• A. A-G and T-C
• B. A-T and C-G
• C. -A and T-T
• D. C-C and G-G

Correct answer: B

Rationale: Rationale: In DNA, nitrogenous bases pair with each other in a specific manner known as complementary base pairing. Adenine (A) always pairs with Thymine (T), and Cytosine (C) always pairs with Guanine (G). This pairing is essential for maintaining the structure and function of DNA. Therefore, option B is the correct answer as it correctly identifies the nitrogenous bases that pair with each other in DNA.

5. What is the function of the cell membrane?

• A. To protect the cell and control what enters and exits
• B. To store energy
• C. To produce proteins
• D. To synthesize lipids

Correct answer: A

Rationale: Rationale: The cell membrane, also known as the plasma membrane, serves as a protective barrier for the cell, separating the internal environment of the cell from the external environment. It is selectively permeable, meaning it controls the passage of substances in and out of the cell. This regulation of what enters and exits the cell is crucial for maintaining the cell's internal environment and ensuring proper functioning. Options B, C, and D are incorrect because storing energy, producing proteins, and synthesizing lipids are functions carried out by other cellular structures such as mitochondria, ribosomes, and endoplasmic reticulum, respectively, not the cell membrane.

6. A spring with a spring constant of 100 N/m is stretched 0.2 m from its equilibrium position. What is the potential energy stored in the spring?

• A. 2 J
• B. 4 J
• C. 8 J
• D. 20 J

Correct answer: B

Rationale: Potential energy in a spring is calculated as 1/2 * k * x², where k is the spring constant and x is the displacement from equilibrium. Therefore, the potential energy is 1/2 * 100 N/m * (0.2 m)² = 4 J.

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