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. What is the main factor affecting the acceleration of a ball rolling down an inclined plane?

• A. The material of the ball
• B. The angle of the incline
• C. The air resistance
• D. The ball's initial velocity

Correct answer: B

Rationale: The main factor affecting the acceleration of a ball rolling down an inclined plane is the angle of the incline. The steeper the incline, the greater the component of the gravitational force acting parallel to the incline, leading to a higher acceleration of the ball. While the material of the ball, air resistance, and the ball's initial velocity may have some influence on the motion, the angle of the incline is the primary factor determining acceleration in this scenario. The material of the ball does not significantly affect its acceleration on the incline unless it impacts the friction with the surface. Air resistance plays a minor role in the acceleration of the ball compared to the gravitational force. The ball's initial velocity affects the speed at the start but does not influence the acceleration down the incline.

3. Which element shares the same group (family) on the periodic table with helium (He)?

• A. Neon (Ne)
• B. Boron (B)
• C. Carbon (C)
• D. Oxygen (O)

Correct answer: A

Rationale: Elements within the same group share similar electron configurations in their outermost shells, resulting in comparable chemical properties. Helium and Neon both belong to Group 18 (Noble Gases), explaining their similarities. Boron, Carbon, and Oxygen are not in the same group as Helium on the periodic table. Boron is in Group 13, Carbon is in Group 14, and Oxygen is in Group 16, which are different from Helium's Group 18.

4. Why is the stratified squamous epithelium found in the skin adapted for?

• A. Absorption
• B. Secretion
• C. Protection
• D. Gas exchange

Correct answer: C

Rationale: The stratified squamous epithelium found in the skin is adapted for protection. This type of epithelium forms a tough, protective barrier against physical, chemical, and biological damage. Its multiple layers of cells help prevent the entry of pathogens and reduce water loss from the body, making it essential for shielding the underlying tissues. Choices A, B, and D are incorrect because stratified squamous epithelium is not specialized for absorption, secretion, or gas exchange. Instead, its primary function is to protect the underlying tissues and organs from external damage and dehydration.

5. During gas exchange in the alveoli, what happens to oxygen?

• A. Oxygen is released from the alveoli into the bloodstream.
• B. Oxygen is absorbed from the alveoli into the bloodstream.
• C. Oxygen is converted into carbon dioxide.
• D. Oxygen is stored in the alveoli for later use.

Correct answer: B

Rationale: During gas exchange in the alveoli, oxygen is absorbed from the alveoli into the bloodstream. This process occurs due to the difference in partial pressures of oxygen between the alveoli and the bloodstream, causing oxygen to move from an area of higher concentration (alveoli) to an area of lower concentration (bloodstream). Oxygen is then transported by red blood cells to tissues throughout the body for cellular respiration. Choice A is incorrect as oxygen moves from the alveoli into the bloodstream, not the other way around. Choice C is incorrect as oxygen is not converted into carbon dioxide during gas exchange. Choice D is incorrect as oxygen is not stored in the alveoli but rather continuously exchanged with carbon dioxide during respiration.

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