Nursing Elites

1. Which of the following cations is found at the center of a heme?

• A. Cr (III)
• B. Cu (II)
• C. Iron (II)
• D. Iron (III)

Correct answer: C

Rationale: The correct answer is Iron (II) (Fe2+), which is the cation found at the center of a heme group. Heme contains an iron (II) ion that is coordinated within the porphyrin ring structure. This iron ion is crucial for the function of heme in binding and transporting oxygen in hemoglobin and myoglobin. Choice A (Cr (III)) is incorrect as chromium is not typically found at the center of a heme group. Choice B (Cu (II)) is incorrect as copper is not the cation typically present in heme. Choice D (Iron (III)) is also incorrect as heme predominantly contains iron (II) at its center, not iron (III).

2. A car brakes to a stop on a level road. Which of the following forces does NOT do work on the car?

• A. The braking force applied by the wheels
• B. The normal force from the road
• C. The gravitational force on the car
• D. The friction force between the tires and the road

Correct answer: B

Rationale: The normal force from the road does not do work on the car because it is perpendicular to the direction of motion. Work is defined as force applied in the direction of motion, so the normal force, which acts perpendicular to the motion of the car, does not contribute to the work done on the car. The braking force applied by the wheels, the gravitational force on the car, and the friction force between the tires and the road all act in the direction of motion and contribute to the work done on the car. In this scenario, the normal force is supporting the weight of the car and keeping it from sinking into the road, but it does not transfer energy to the car as it moves.

3. Which hormone, produced by the pancreas, is involved in the regulation of blood sugar levels by inhibiting the release of insulin and promoting the release of glucose into the bloodstream?

• A. Insulin
• B. Glucagon
• C. Cortisol
• D. Somatostatin

Correct answer: D

Rationale: The correct answer is D, Somatostatin. Somatostatin is a hormone produced by the pancreas that plays a crucial role in regulating blood sugar levels by inhibiting the release of insulin and promoting the release of glucose into the bloodstream. It acts as a counterbalance to insulin, preventing excess insulin secretion and ensuring the availability of glucose when needed. Therefore, somatostatin helps maintain blood sugar balance in the body. Choices A, B, and C are incorrect. Insulin is responsible for lowering blood sugar levels, while glucagon and cortisol have roles that differ from the functions described in the question.

4. Which of the following is NOT a greenhouse gas?

• A. Carbon dioxide
• B. Water vapor
• C. Nitrogen
• D. Methane

Correct answer: C

Rationale: Rationale: A) Carbon dioxide: Carbon dioxide is a greenhouse gas that is naturally present in the Earth's atmosphere and is also released through human activities such as burning fossil fuels. B) Water vapor: Water vapor is a greenhouse gas that is naturally present in the atmosphere and plays a significant role in the Earth's climate system. C) Nitrogen: Nitrogen is not considered a greenhouse gas because it does not have the ability to absorb and emit infrared radiation in the same way that greenhouse gases like carbon dioxide and methane do. D) Methane: Methane is a potent greenhouse gas that is released through natural processes such as wetland decomposition and human activities such as livestock farming and fossil fuel extraction. Therefore, the correct answer is C) Nitrogen, as it is not a greenhouse gas.

5. When baking soda (sodium bicarbonate) reacts with vinegar (acetic acid), what type of reaction occurs?

• A. Combustion
• B. Double displacement
• C. Decomposition
• D. Synthesis

Correct answer: B

Rationale: When baking soda (sodium bicarbonate) reacts with vinegar (acetic acid), a double displacement reaction occurs. In this reaction, the positive ions in baking soda switch places with the positive ions in vinegar to form water, carbon dioxide, and a salt. Combustion involves a reaction with oxygen to produce heat and light energy. Decomposition is the breakdown of a compound into simpler substances, which is not the case in the given reaction. Synthesis is the combination of substances to form a more complex compound, which is also not the type of reaction observed when baking soda and vinegar react.

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