Nursing Elites

1. Which of the following cations is found at the center of a heme?

• A. Cr (III)
• B. Cu (II)
• C. Iron (II)
• D. Iron (III)

Correct answer: C

Rationale: The correct answer is Iron (II) (Fe2+), which is the cation found at the center of a heme group. Heme contains an iron (II) ion that is coordinated within the porphyrin ring structure. This iron ion is crucial for the function of heme in binding and transporting oxygen in hemoglobin and myoglobin. Choice A (Cr (III)) is incorrect as chromium is not typically found at the center of a heme group. Choice B (Cu (II)) is incorrect as copper is not the cation typically present in heme. Choice D (Iron (III)) is also incorrect as heme predominantly contains iron (II) at its center, not iron (III).

2. Which of the following terms describes stem cells that have the ability to develop into any cell found in the human body?

• A. Totipotent stem cells
• B. Multipotent stem cells
• C. Pluripotent stem cells
• D. Hematopoietic stem cells

Correct answer: A

Rationale: Totipotent stem cells have the unique ability to differentiate into any cell type in the human body and can generate a complete organism. They are considered the most versatile type of stem cells, capable of developing into all cell types, including extraembryonic tissues. Choice A, Totipotent stem cells, is the correct answer as it specifically describes stem cells with the broadest differentiation potential. Choice B, Multipotent stem cells, refers to stem cells that can differentiate into a limited range of cell types. Choice C, Pluripotent stem cells, can give rise to almost all cell types, but not the complete organism like totipotent stem cells. Choice D, Hematopoietic stem cells, are a type of multipotent stem cells that give rise to various blood cell types, but do not have the same broad differentiation potential as totipotent stem cells.

3. The spleen, a large lymphatic organ, is located in the:

• A. Chest
• B. Abdomen
• C. Pelvis
• D. Head and neck

Correct answer: B

Rationale: The spleen is located in the abdomen, specifically in the upper left part of the abdomen, under the ribcage and above the stomach. It is an important organ in the lymphatic system responsible for filtering blood, storing blood cells, and fighting infection. It is not located in the chest, pelvis, or head and neck regions. Therefore, the correct answer is 'B: Abdomen.' Choices 'A: Chest,' 'C: Pelvis,' and 'D: Head and neck' are incorrect as the spleen is not situated in these anatomical areas.

4. What happens to the internal energy of a system when it performs work on its surroundings?

• A. It increases.
• B. It decreases.
• C. It remains the same.
• D. Insufficient information.

Correct answer: B

Rationale: When a system performs work on its surroundings, it loses energy in the form of work done. This results in a decrease in the internal energy of the system. Work done by the system is considered as negative work, leading to a decrease in internal energy. Therefore, the correct answer is that the internal energy decreases when a system performs work on its surroundings. Choice A is incorrect as the internal energy decreases, not increases. Choice C is incorrect because the internal energy changes due to the work done. Choice D is incorrect because the information provided is sufficient to determine the change in internal energy.

5. What is the process of combining two or more substances to form a heterogeneous mixture called?

• A. Dissolving
• B. Diluting
• C. Mixing
• D. Reacting

Correct answer: C

Rationale: The correct answer is 'Mixing.' When substances are combined, a heterogeneous mixture is formed where the components are physically distinguishable. 'Dissolving' (Choice A) is the process of a solute becoming uniformly dispersed in a solvent to form a solution, not a heterogeneous mixture. 'Diluting' (Choice B) refers to reducing the concentration of a solute in a solution. 'Reacting' (Choice D) involves a chemical change where substances interact to form new products, rather than just physically mixing to form a heterogeneous mixture.

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