Nursing Elites

1. What is a rod-shaped structure that forms when a single DNA molecule and its associated proteins coil tightly before cell division?

• A. Centromere
• B. Chromatid
• C. Chromosome
• D. Gene

Correct answer: C

Rationale: A chromosome is a rod-shaped structure that forms when a single DNA molecule and its associated proteins coil tightly before cell division. It contains the genetic material and is essential for cell division and replication. The centromere is a specific region of a chromosome that plays a role in cell division. A chromatid is one half of a duplicated chromosome, and a gene is a unit of heredity responsible for specific traits. Therefore, the correct answer is 'Chromosome' as it represents the entire condensed DNA molecule during cell division.

2. In a study where fish are fed different amounts of food daily for four weeks in separate tanks, with fish weight measured weekly, what is the dependent variable?

• A. Weight of the fish
• B. Type of food used
• C. Number of fish tanks
• D. Frequency of feedings

Correct answer: A

Rationale: The weight of the fish is the dependent variable in this study because it is the outcome being measured in response to the varying feeding amounts. The weight of the fish changes based on the feeding regimen, making it the dependent variable. The type of food used (choice B), number of fish tanks (choice C), and frequency of feedings (choice D) are not the dependent variables in this study. These factors may be independent variables that are manipulated or controlled in the experiment to observe their impact on the dependent variable, which is the weight of the fish.

3. Calcitonin, a hormone that helps regulate calcium levels, is produced by the:

• A. Thyroid gland
• B. Parathyroid gland
• C. Thymus gland
• D. Adrenal gland

Correct answer: A

Rationale: Calcitonin is a hormone produced by the thyroid gland. It helps regulate calcium levels in the body by inhibiting the breakdown of bone and promoting calcium excretion by the kidneys. The parathyroid gland produces parathyroid hormone (PTH), which works in opposition to calcitonin to regulate calcium levels. The thymus gland is involved in the development of the immune system, and the adrenal gland produces hormones such as cortisol and adrenaline. Therefore, the correct answer is the thyroid gland as it specifically secretes calcitonin for calcium regulation.

4. Which of the following substances is typically a good conductor of electricity when dissolved in water?

• A. Sugar
• B. Sodium chloride
• C. Olive oil
• D. Oxygen gas

Correct answer: B

Rationale: Sodium chloride (table salt) is typically a good conductor of electricity when dissolved in water because it dissociates into ions (sodium cations and chloride anions) that can carry an electric current. Sugar (choice A), olive oil (choice C), and oxygen gas (choice D) do not dissociate into ions in water and therefore are not good conductors of electricity. Sugar does not dissociate into ions in water, so it cannot conduct electricity. Olive oil and oxygen gas are nonpolar substances and do not ionize in water, making them poor conductors of electricity.

5. What is the name of the growth plates in children's bones where new bone tissue is formed?

• A. Epiphyses
• B. Diaphysis
• C. Periosteum
• D. Medullary cavity

Correct answer: A

Rationale: The correct answer is A: Epiphyses. Epiphyses are cartilaginous areas found at the ends of long bones, enabling growth and bone lengthening during childhood and adolescence. The diaphysis refers to the main shaft of a long bone. The periosteum is the outer bone layer responsible for nourishment and aiding in bone repair. The medullary cavity is the central cavity within the diaphysis that contains bone marrow but is not involved in new bone tissue formation.

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