Nursing Elites

1. Most catalysts found in biological systems are which of the following?

• A. Special lipids called cofactors.
• B. Special proteins called enzymes.
• C. Special lipids called enzymes.
• D. Special proteins called cofactors.

Correct answer: B

Rationale: Enzymes are special proteins that act as catalysts in biological systems. They accelerate chemical reactions by lowering the activation energy required for the reaction to occur. Enzymes play a critical role in the regulation of metabolic pathways and are essential for various biological processes. While some enzymes may require cofactors for activity, the enzymes themselves are the catalysts in biological systems. Therefore, choice B, special proteins called enzymes, is the most suitable answer. Choices A, C, and D are incorrect because enzymes, not lipids, are the primary catalysts in biological systems.

2. Which of the following bones belongs to the category of long bones?

• A. Femur
• B. Ribs and cranial bones
• C. Sesamoid
• D. Vertebrae and hip bones

Correct answer: A

Rationale: The correct answer is A: Femur. Long bones are characterized by their elongated shape, with examples including the femur, humerus, and tibia. These bones are essential for support, movement, and bone marrow production. Choice B, 'Ribs and cranial bones,' consists of flat bones, not long bones. Choice C, 'Sesamoid,' refers to small bones embedded within tendons and do not fall under the category of long bones. Choice D, 'Vertebrae and hip bones,' includes irregular bones that provide structural support and protection for vital organs, but they are not classified as long bones.

3. Which of the following areas of the body has the most sweat glands?

• A. Upper back
• B. Arms
• C. Feet
• D. Palms

Correct answer: D

Rationale: The correct answer is D: Palms. The palms of the hands have the highest concentration of sweat glands compared to other areas of the body. This is why sweating is commonly noticed on the palms during times of stress or physical exertion. Choices A, B, and C are incorrect. While these areas do have sweat glands, they are not as densely distributed as in the palms. The upper back, arms, and feet do contribute to overall body sweat, but the palms have a significantly higher density of sweat glands, making them the area with the most sweat glands.

4. How many mL of a 0 M stock solution of HCl should be added to water to create 250 mL of a 50 M solution of HCl?

• A. 31.25 mL
• B. 32 mL
• C. 30 mL
• D. 31.3 mL

Correct answer: B

Rationale: To prepare 250 mL of a 50 M solution of HCl, the formula V1 x C1 = V2 x C2 is used, where V1 is the volume of the stock solution, C1 is the concentration of the stock solution, V2 is the final volume of the desired solution, and C2 is the final concentration of the desired solution. Given V1 x 0 M = 250 mL x 50 M, solving for V1 results in V1 = (250 mL x 50 M) / 0 M = 32 mL. Therefore, 32 mL of the 0 M stock solution of HCl needs to be added to water to create a 250 mL solution of 50 M HCl. Choices A, C, and D are incorrect because they do not represent the accurate volume required for the dilution calculation based on the given concentrations and volumes in the problem.

5. 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.

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