Nursing Elites

1. What property of a substance remains constant regardless of changes in its shape or size?

• A. Mass
• B. Weight
• C. Density
• D. Volume

Correct answer: A

Rationale: Mass is a measure of the amount of matter in an object and remains constant regardless of changes in its shape or size. Weight, density, and volume can all change depending on the conditions, but mass remains the same. For example, if you have a piece of clay and you shape it into a ball or flatten it into a pancake, the amount of clay (mass) will remain the same, even though the shape and size have changed. Weight is the force acting on an object due to gravity, which can vary depending on the gravitational pull. Density is the mass per unit volume, so it changes with variations in volume. Volume is the amount of space occupied by an object, which can change if the shape or size of the object is altered.

2. Which organ produces insulin?

• A. Pancreas
• B. Liver
• C. Stomach
• D. Kidneys

Correct answer: A

Rationale: Insulin is a hormone that regulates blood sugar levels by facilitating the uptake of glucose into cells for energy production or storage. The pancreas, located behind the stomach, is the organ responsible for producing insulin. Within the pancreas, specialized cells known as beta cells synthesize and secrete insulin in response to changes in blood glucose levels. The liver, although vital for metabolism, does not produce insulin. Similarly, the stomach and kidneys do not play a role in insulin production. Hence, the correct answer is the pancreas.

3. Which statement most accurately compares and contrasts the structures of DNA and RNA?

• A. Both DNA and RNA have 4 nucleotide bases. Three of the bases are the same, but the fourth base is thymine in DNA and uracil in RNA.
• B. Both DNA and RNA have the same 4 nucleotide bases. However, the nucleotides bond differently in DNA compared to RNA.
• C. Both DNA and RNA have different numbers of nucleotide bases. DNA is a double helix while RNA is a single strand.
• D. Both DNA and RNA have a double helix structure. However, DNA contains 6 nucleotide bases and RNA contains 4 nucleotide bases.

Correct answer: A

Rationale: The correct answer is A because DNA and RNA both consist of 4 nucleotide bases, namely adenine, cytosine, and guanine, which are common in both. The key difference lies in the fourth base, which is thymine in DNA and uracil in RNA. This distinction is fundamental in understanding the structural variances between DNA and RNA. Choice B is incorrect as it incorrectly states that the nucleotides bond differently in DNA compared to RNA without specifying the crucial base differences. Choice C is inaccurate as it misrepresents the numbers of nucleotide bases in DNA and RNA, and incorrectly describes DNA as a double helix and RNA as a single strand, which is not related to the difference in bases. Choice D is incorrect as it inaccurately portrays DNA with 6 nucleotide bases and RNA with 4, which is not true; both DNA and RNA have 4 nucleotide bases, but with differences in one of the bases.

4. What is the primary factor that determines whether a solute will dissolve in a solvent?

• A. Temperature
• B. Pressure
• C. Molecular structure
• D. Particle size

Correct answer: C

Rationale: The primary factor that determines whether a solute will dissolve in a solvent is the molecular structure. The compatibility of the solute's molecules with the solvent's molecules is crucial for dissolution to occur. While temperature, pressure, and particle size can influence the rate of dissolution, they are not the primary factors determining solubility. Molecular structure plays a key role in determining if a solute will form favorable interactions with the solvent, which is essential for dissolution to take place effectively. Temperature can affect solubility by changing the kinetic energy of molecules, pressure typically has a minor effect on solubility except for gases, and particle size influences the rate of dissolution by increasing surface area, but none of these factors are as fundamentally important as molecular structure in determining solubility.

5. How does the stability of an atom's nucleus influence its radioactive decay?

• A. Stable nuclei never undergo radioactive decay.
• B. Unstable nuclei are more likely to decay through various processes.
• C. Decay releases energy, making stable nuclei more prone to it.
• D. The element's position on the periodic table determines its decay rate.

Correct answer: B

Rationale: Unstable nuclei are more likely to decay through various processes. The stability of an atom's nucleus is a crucial factor in determining whether it will undergo radioactive decay. Unstable nuclei have an excess of either protons or neutrons, causing an imbalance in the nucleus. To achieve a more stable configuration, these nuclei will undergo radioactive decay by emitting particles or energy. On the contrary, stable nuclei are less likely to undergo radioactive decay as they possess a balanced number of protons and neutrons. Choice A is incorrect because stable nuclei can still undergo radioactive decay, albeit less frequently. Choice C is incorrect as decay does not make stable nuclei more prone to it; rather, it stabilizes them. Choice D is incorrect because an element's decay rate is primarily determined by the nucleus's stability, not its position on the periodic table.

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