Nursing Elites

1. What element is responsible for the green color of leaves?

• A. Magnesium
• B. Iron
• C. Copper
• D. Zinc

Correct answer: A

Rationale: Magnesium is the correct answer. It is essential for the formation of chlorophyll, the green pigment in plants that is crucial for photosynthesis. Chlorophyll absorbs sunlight and uses its energy to convert carbon dioxide and water into glucose and oxygen. Iron, copper, and zinc do not play a direct role in the green color of leaves. Iron is more related to processes like electron transport, copper is involved in enzyme functions, and zinc contributes to the synthesis of plant growth regulators.

2. Which structure in the lungs is the site of gas exchange?

• A. Trachea
• B. Alveoli
• C. Bronchioles
• D. Diaphragm

Correct answer: B

Rationale: The correct answer is B: Alveoli. Alveoli are tiny air sacs in the lungs where gas exchange occurs. Oxygen from inhaled air diffuses into the bloodstream, while carbon dioxide from the blood is released into the alveoli to be exhaled. The trachea (Choice A) is the windpipe that carries air to and from the lungs, but it is not involved in gas exchange. Bronchioles (Choice C) are small air passages within the lungs that branch off from the bronchi, leading air to the alveoli but not directly involved in gas exchange. The diaphragm (Choice D) is a muscle below the lungs that helps in breathing by expanding and contracting the chest cavity, but it is not the site of gas exchange.

3. Which of the following is an example of a salt?

• A. Sodium hydroxide (NaOH)
• B. Hydrochloric acid (HCl)
• C. Sodium chloride (NaCl)
• D. Sulfuric acid (H₂SO₄)

Correct answer: C

Rationale: Sodium chloride (NaCl) is an example of a salt. Salts are ionic compounds formed by the reaction of an acid with a base. In this case, sodium chloride is formed by the reaction of sodium hydroxide (a base) with hydrochloric acid (an acid). Sodium hydroxide (NaOH), hydrochloric acid (HCl), and sulfuric acid (H₂SO₄) are not salts because they are not formed by the neutralization reaction of an acid and a base, which is a characteristic of salts.

4. What type of energy is stored in food?

• A. Mechanical energy
• B. Kinetic energy
• C. Chemical potential energy
• D. Thermal energy

Correct answer: C

Rationale: Food stores energy in the form of chemical potential energy. This energy is released during digestion and metabolism to provide the body with the energy it needs to function. It is derived from the bonds within the molecules of food, such as carbohydrates, fats, and proteins. Choice A, mechanical energy, is incorrect as food does not store energy in the form of mechanical energy. Choice B, kinetic energy, is incorrect as kinetic energy is associated with the motion of objects, not stored in food. Choice D, thermal energy, is incorrect as thermal energy relates to heat energy, which is not the primary form of energy stored in food.

5. Which of the following neurotransmitters slows down the activity of neurons to prevent overexcitation?

• A. Acetylcholine
• B. Dopamine
• C. GABA
• D. Serotonin

Correct answer: C

Rationale: The correct answer is C: GABA (gamma-aminobutyric acid). GABA is an inhibitory neurotransmitter that slows down neuronal activity, helping to prevent overexcitation in the brain. It counterbalances the effects of excitatory neurotransmitters like glutamate, playing a crucial role in maintaining the balance of neuronal activity in the brain. Acetylcholine (Choice A) is primarily an excitatory neurotransmitter involved in muscle movement and cognitive functions. Dopamine (Choice B) plays a role in reward-motivated behavior and motor control. Serotonin (Choice D) is involved in regulating mood, appetite, and sleep but is not primarily responsible for slowing down neuronal activity to prevent overexcitation.

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