Nursing Elites

1. Which property of a substance refers to its ability to be stretched into thin wires?

• A. Conductivity
• B. Viscosity
• C. Ductility
• D. Malleability

Correct answer: C

Rationale: Ductility is the property of a substance that allows it to be stretched into thin wires without breaking. It is a crucial property for materials used in wire production. Conductivity refers to the ability of a substance to conduct electricity or heat, not to be stretched into wires. Viscosity is the measure of a fluid's resistance to flow, not its ability to be stretched. Malleability is the property of a substance that allows it to be hammered or rolled into thin sheets, not stretched into wires.

2. What is the name for the sac-shaped structures in which carbon dioxide and oxygen exchange takes place?

• A. Kidneys
• B. Medulla oblongata
• C. Alveoli
• D. Bronchioles

Correct answer: C

Rationale: The alveoli are the tiny sac-shaped structures in the lungs where gas exchange occurs. Oxygen from the air we breathe diffuses into the bloodstream through the alveoli, while carbon dioxide, a waste product produced by cells, is removed from the blood and exhaled out of the body through the alveoli. Choices A, B, and D are incorrect. Kidneys are organs responsible for filtering waste from the blood, the medulla oblongata is a part of the brain responsible for autonomic functions, and bronchioles are smaller airway passages in the lungs that branch off from the bronchi.

3. Where does the maturation of T-cells and the production of T-cell receptors occur?

• A. Thymus
• B. Spleen
• C. Lymph nodes
• D. Bone marrow

Correct answer: A

Rationale: The correct answer is the Thymus. T-cells mature and develop their receptors in the thymus gland, making it a vital organ for the immune system. The thymus provides the necessary environment for T-cells to differentiate and acquire their specific receptors and functions, which are essential for their role in the adaptive immune response. The spleen, lymph nodes, and bone marrow are all important components of the immune system, but they do not primarily serve as sites for T-cell maturation and T-cell receptor production.

4. 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).

5. Which type of reaction undergoes hydrolysis?

• A. Anabolism
• B. Catabolism
• C. Exothermic
• D. Endothermic

Correct answer: B

Rationale: The correct answer is 'Catabolism.' Catabolic reactions involve the breakdown of larger molecules into smaller ones, often through hydrolysis, where water is added to break chemical bonds. This process is essential for the degradation of complex molecules and the release of energy stored in chemical bonds. Choice A, 'Anabolism,' is incorrect as anabolism involves the synthesis of complex molecules from simpler ones. Choices C and D, 'Exothermic' and 'Endothermic,' refer to the heat energy exchange during a reaction and are not directly related to the process of hydrolysis.

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