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. Chromatids divide into identical chromosomes and migrate to opposite ends of the cell in which of the following phases of mitosis?

• A. metaphase
• B. anaphase
• C. prophase
• D. telophase

Correct answer: B

Rationale: During anaphase of mitosis, the sister chromatids detach from each other and migrate to opposite poles of the cell. This process ensures that each daughter cell ultimately receives an identical set of chromosomes, as the chromatids separate and become individual chromosomes again. This is a crucial step in ensuring accurate distribution of genetic material during cell division. In metaphase, the chromosomes align at the cell's equator but do not separate yet. Prophase is the phase where chromatin condenses into chromosomes and the nuclear envelope breaks down. Telophase is the final phase where the nuclear envelope reforms around the separated chromosomes.

3. Which of the following terms refers to a muscle twitch, a single forceful contraction of a muscle fiber?

• A. Tetanus
• B. Tremor
• C. Fasciculation
• D. Rigidity

Correct answer: C

Rationale: The correct term for a muscle twitch, a single forceful contraction of a muscle fiber, is 'Fasciculation' (choice C). Fasciculation specifically describes this phenomenon. 'Tetanus' (choice A) refers to sustained muscle contraction, 'Tremor' (choice B) indicates a shaky or quivering movement, and 'Rigidity' (choice D) denotes stiffness or inflexibility in muscles. Therefore, choices A, B, and D are incorrect in the context of a single forceful contraction of a muscle fiber.

4. How are kidney stones formed?

• A. Due to excess water not being reabsorbed
• B. When minerals crystallize in the urine
• C. When electrolytes become too concentrated
• D. All of the above

Correct answer: B

Rationale: Kidney stones are formed when minerals in the urine crystallize and stick together to form solid masses. Excess water not being reabsorbed (option A) does not directly contribute to kidney stone formation. Similarly, electrolytes becoming too concentrated (option C) is not a direct cause of kidney stone formation. The correct answer is B because the crystallization of minerals in the urine leads to the formation of kidney stones.

5. What type of inheritance pattern results in a 3:1 ratio of dominant to recessive phenotypes in the F2 generation?

• A. Incomplete dominance
• B. Codominance
• C. Sex-linked inheritance
• D. Autosomal dominant inheritance

Correct answer: D

Rationale: Autosomal dominant inheritance results in a 3:1 ratio of dominant to recessive phenotypes in the F2 generation. This inheritance pattern occurs when a single copy of the dominant allele is enough to express the dominant phenotype. A) Incomplete dominance: In incomplete dominance, the heterozygous phenotype is a blend of the two homozygous phenotypes, and it does not lead to a 3:1 ratio of dominant to recessive phenotypes in the F2 generation. B) Codominance: In codominance, both alleles are fully expressed in the heterozygous phenotype, but this pattern also does not result in a 3:1 ratio of dominant to recessive phenotypes in the F2 generation. C) Sex-linked inheritance: Sex-linked inheritance involves genes located on the sex chromosomes and does not typically lead to a 3:1 ratio of dominant to recessive phenotypes in the F2 generation.

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