Nursing Elites

1. Which property of matter explains why ice floats on water?

• A. Viscosity
• B. Density
• C. Buoyancy
• D. Surface tension

Correct answer: c

Rationale: Buoyancy is the upward force exerted by a fluid (like water) on an object immersed in it. Ice floats on water because it is less dense than water, experiencing an upward force (buoyancy) greater than its weight.

2. You need to repaint a cylindrical water tank with a diameter of 2 meters and a height of 3 meters. Assuming one can of paint covers 10 sq m, how many cans do you need (consider only the exterior surface)?

• A. 6 cans
• B. 9 cans
• C. 12 cans
• D. 15 cans

Correct answer: C

Rationale: Calculate the surface area of the cylinder and divide by the coverage area per can.

3. A condition characterized by an overactive thyroid gland and excessive production of thyroid hormones is called:

• A. Diabetes mellitus
• B. Hyperthyroidism
• C. Hypothyroidism
• D. Cushing's syndrome

Correct answer: B

Rationale: The correct answer is B: Hyperthyroidism. Hyperthyroidism is a condition where the thyroid gland becomes overactive and produces an excess of thyroid hormones. This can lead to symptoms such as weight loss, rapid heart rate, and anxiety. Diabetes mellitus (A) is a condition characterized by high blood sugar levels. Hypothyroidism (C) is the opposite of hyperthyroidism, where the thyroid gland is underactive. Cushing's syndrome (D) is a disorder caused by prolonged exposure to high levels of the hormone cortisol. Therefore, in this case, the correct answer is B as it specifically relates to an overactive thyroid gland.

4. Electrons occupy specific energy levels around the nucleus with varying probabilities. The electron cloud model depicts electrons existing in distinct energy levels, not fixed orbits, with probabilities of finding them in specific regions.

• A. 2 protons and 6 neutrons
• B. 2 filled s orbitals and 6 filled p orbitals
• C. 2s orbitals with 2 and 6 electrons, respectively
• D. 4 filled electron shells

Correct answer: B

Rationale: 2 filled s orbitals and 6 filled p orbitals. This notation indicates two electrons in the 2s orbital and six electrons in the 2p orbitals.

5. In what way does spindle fiber dynamics and microtubule attachment regulate cell cycle checkpoints?

• A. Misaligned chromosomes fail to attach to microtubules, triggering a delay in anaphase onset.
• B. The presence of unattached kinetochores on the centromeres sends a signal to pause cell cycle progression.
• C. Microtubule instability and rapid depolymerization lead to the activation of checkpoint proteins.
• D. All of the above.

Correct answer: D

Rationale: Rationale: A) Misaligned chromosomes fail to attach to microtubules, triggering a delay in anaphase onset: During cell division, proper attachment of chromosomes to spindle fibers is crucial for accurate segregation of genetic material. If chromosomes are not correctly attached to microtubules, it can lead to misalignment, which triggers a delay in anaphase onset. This delay allows the cell to correct any errors before proceeding with cell division. B) The presence of unattached kinetochores on the centromeres sends a signal to pause cell cycle progression: Kinetochores are protein structures located at the centromere of chromosomes and are responsible for attaching chromosomes to spindle fibers. When kinetochores are unattached or improperly attached to microtubules, it sends a signal to the cell to pause cell cycle progression. This pause allows the cell to ensure that all chromosomes are properly aligned before proceeding with cell division.

6. What is the name for the change in enthalpy (heat) associated with a chemical reaction at constant pressure?

• A. Entropy
• B. Enthalpy
• C. Gibbs free energy
• D. Heat of reaction

Correct answer: D

Rationale: The correct answer is D, Heat of reaction. The heat of reaction, also known as the enthalpy change, is the amount of heat absorbed or released during a chemical reaction at constant pressure. Entropy (A) is a measure of the disorder or randomness of a system. Enthalpy (B) is the total heat content of a system. Gibbs free energy (C) is a measure of the energy available to do work in a system at constant temperature and pressure.

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