Nursing Elites

1. Which of the following units is used to express concentration as a mass of solute per unit volume of solution?

• A. Molality (m)
• B. Molarity (M)
• C. Weight percent (%)
• D. Parts per million (ppm)

Correct answer: A

Rationale: Molality (m) is the unit used to express concentration as a mass of solute per unit volume of solution. It is calculated by dividing the mass of solute in grams by the mass of the solvent in kilograms. Molality is preferred over molarity when there are large temperature variations as it is temperature-independent, making it a more accurate measure of concentration. Molarity (B) is the unit used to express concentration as moles of solute per liter of solution, weight percent (C) is the mass of solute per 100 parts of the total mass of the solution, and parts per million (D) is used to express very small concentrations where 1 ppm is equivalent to 1 mg of solute per liter of solution.

2. Which types of glial cells are found in the CNS?

• A. Schwann cells, satellite cells
• B. Astrocytes, microglia, ependymal cells, oligodendrocytes
• C. Satellite cells, microglia, oligodendrocytes
• D. Astrocytes, Schwann cells, satellite cells

Correct answer: B

Rationale: The correct answer is B. Glial cells in the CNS include astrocytes, microglia, ependymal cells, and oligodendrocytes. Schwann cells and satellite cells are found in the PNS. Astrocytes are the most abundant type of glial cells and are involved in nutrient support, repair, and maintenance of the extracellular environment. Microglia are the resident immune cells of the CNS, playing a role in immune defense. Ependymal cells line the ventricles of the brain and the central canal of the spinal cord, contributing to the production and circulation of cerebrospinal fluid. Oligodendrocytes are responsible for producing myelin, which insulates axons in the CNS. Understanding the specific functions of each type of glial cell is essential in grasping the complexity of the central nervous system's support and protective mechanisms.

3. Which of the following is responsible for transporting oxygen in the blood?

• A. White blood cells
• B. Red blood cells
• C. Platelets
• D. Plasma

Correct answer: B

Rationale: Red blood cells are responsible for transporting oxygen in the blood. Hemoglobin, a protein found in red blood cells, binds to oxygen in the lungs and carries it to tissues throughout the body. White blood cells are involved in the immune system's defense mechanisms against infections, platelets help in blood clotting, and plasma is the liquid component of blood that carries various substances like nutrients, hormones, and waste products.

4. When an atom gains or loses electrons, it becomes a(n):

• A. Molecule
• B. Isotope
• C. Ion
• D. Compound

Correct answer: C

Rationale: When an atom gains or loses electrons, it becomes an ion. Gaining or losing electrons alters the atom's electron count and charge, creating a positively or negatively charged ion. A molecule is formed when two or more atoms are chemically bonded. An isotope is a variation of an element with a different number of neutrons. A compound consists of two or more different elements chemically bonded together.

5. What is the 3D structure of a protein called?

• A. Tertiary structure
• B. Secondary structure
• C. Primary structure
• D. Quaternary structure

Correct answer: A

Rationale: - Primary structure refers to the linear sequence of amino acids in a protein. - Secondary structure refers to local folded structures within a protein, such as alpha helices and beta sheets. - Tertiary structure is the overall 3D shape of a protein, which is determined by interactions between amino acid side chains and the environment. - Quaternary structure refers to the arrangement of multiple protein subunits in a protein complex. Therefore, the 3D structure of a protein is called the tertiary structure because it represents the overall folding of the protein into a specific shape.

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