Nursing Elites

1. Where does most of the chemical digestion and absorption of nutrients occur?

• A. Mouth
• B. Stomach
• C. Small intestine
• D. Large intestine

Correct answer: C

Rationale: The small intestine is the primary site for both chemical digestion and absorption of nutrients in the digestive system. The lining of the small intestine is equipped with villi and microvilli, which significantly increase the surface area available for absorption. Enzymes from the pancreas and bile from the liver play crucial roles in further breaking down food into absorbable molecules that can pass through the intestinal wall into the bloodstream. While the stomach assists in mechanical breakdown and initial protein digestion, it is not the main site of nutrient absorption. The large intestine, on the other hand, mainly absorbs water and electrolytes from undigested food particles. The mouth aids in initial mechanical breakdown and some carbohydrate digestion, but the majority of nutrient absorption occurs in the small intestine, making it the correct answer.

2. What is the primary function of the liver in the digestive system?

• A. To absorb water
• B. To produce bile
• C. To store glucose
• D. To regulate metabolism

Correct answer: B

Rationale: The liver's main function in the digestive system is to produce bile. Bile helps in the digestion and absorption of fats by emulsifying them, breaking down large fat globules into smaller droplets that can be acted upon by digestive enzymes. Choices A, C, and D are incorrect because the liver's primary role in the digestive system is not to absorb water, store glucose, or regulate metabolism. While the liver does have roles in metabolism and glucose regulation, its key function in digestion is bile production.

3. In the reaction 2H2 + O2 → 2H2O, how many moles of oxygen are required to react completely with 4 moles of hydrogen?

• A. 1
• B. 2
• C. 3
• D. 4

Correct answer: B

Rationale: The balanced chemical equation indicates that 2 moles of H2 react with 1 mole of O2 to produce 2 moles of H2O. To determine how many moles of O2 are required to react with 4 moles of H2, you can use the mole ratio from the balanced equation: 2 moles of H2 react with 1 mole of O2. Therefore, to react completely with 4 moles of H2, you would need 2 moles of O2 (4 moles H2 ÷ 2 moles H2 per 1 mole O2). Hence, 2 moles of oxygen are required to react completely with 4 moles of hydrogen. Choices A, C, and D are incorrect because they do not reflect the correct stoichiometry as defined by the balanced chemical equation.

4. What is the main function of lysosomes?

• A. Breaking down and recycling cellular waste
• B. Storing carbohydrates
• C. Synthesizing lipids
• D. Transcribing DNA into mRNA

Correct answer: A

Rationale: The main function of lysosomes is to break down and recycle cellular waste materials, such as old organelles, foreign substances, and cellular debris. This process is crucial for maintaining cellular homeostasis and proper functioning. Storing carbohydrates (B), synthesizing lipids (C), and transcribing DNA into mRNA (D) are not functions typically associated with lysosomes. Storing carbohydrates is primarily done by other organelles like vacuoles. Synthesizing lipids is a function usually associated with the endoplasmic reticulum and transcribing DNA into mRNA occurs in the nucleus by the process of transcription.

5. Which of the following is an example of a secondary alcohol?

• A. Methanol
• B. Ethanol
• C. Isopropanol
• D. Butanol

Correct answer: C

Rationale: Isopropanol is indeed an example of a secondary alcohol because the carbon atom bearing the hydroxyl group is bonded to two other carbon atoms. In isopropanol, the hydroxyl group is attached to a carbon atom that is bonded to two other carbon atoms. Methanol (Choice A) is a primary alcohol with the hydroxyl group attached to a carbon atom that is bonded to one other carbon atom. Ethanol (Choice B) is also a primary alcohol with the hydroxyl group attached to a carbon atom that is bonded to one other carbon atom. Butanol (Choice D) is a primary alcohol with the hydroxyl group attached to a carbon atom that is bonded to three other carbon atoms, making it a primary alcohol.

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