Nursing Elites

1. At what pH does the digestion of protein by pepsin in the stomach require?

• A. 1.8 and 3.5.
• B. 4.8 and 7.0.
• C. 6.8 and 8.5.
• D. 7.8 and 10.0.

Correct answer: A

Rationale: The correct answer is A: 1.8 and 3.5. Pepsin, an enzyme involved in protein digestion, functions optimally in an acidic environment, specifically between pH 1.8 and 3.5. This low pH is necessary for pepsin to break down proteins effectively. Choices B, C, and D are incorrect because pepsin requires a highly acidic environment, ruling out the pH ranges listed in those options.

2. Which gastric enzyme present in infants coagulates milk?

• A. Casein.
• B. Pepsinogen.
• C. Trypsin.
• D. Rennin.

Correct answer: D

Rationale: The correct answer is D, rennin. Rennin is the enzyme in infants responsible for coagulating milk, which aids in the digestion process. Choice A, casein, is a milk protein and not an enzyme. Choices B and C, pepsinogen and trypsin, are digestive enzymes but are not specifically involved in coagulating milk in infants.

3. How can cholesterol absorption be decreased?

• A. Vitamin K.
• B. Plant sterols.
• C. Trans fats.
• D. Phospholipids.

Correct answer: B

Rationale: The correct answer is B: Plant sterols. Plant sterols can reduce cholesterol absorption by competing with cholesterol for absorption sites. Vitamin K, choice A, does not have a significant impact on cholesterol absorption. Trans fats, choice C, are known to increase cholesterol levels rather than decrease absorption. Phospholipids, choice D, play a role in cell structure and are not directly involved in reducing cholesterol absorption.

4. Which lipoprotein carries fat from a meal just consumed to the liver?

• A. Very low-density lipoprotein (VLDL).
• B. Low-density lipoprotein (LDL).
• C. Chylomicrons.
• D. High-density lipoprotein (HDL).

Correct answer: C

Rationale: Chylomicrons are the lipoproteins responsible for transporting dietary fat from the intestines to various tissues, including the liver. VLDL carries lipids synthesized in the liver, LDL transports cholesterol to tissues, and HDL helps transport cholesterol away from tissues to the liver for excretion. Therefore, in the context of carrying fat from a meal just consumed to the liver, chylomicrons are the correct choice.

5. What is the preferred fuel for the cells lining the colon?

• A. Short-chain fatty acids.
• B. Long-chain fatty acids.
• C. Amino acids.
• D. Glucose.

Correct answer: A

Rationale: Short-chain fatty acids are the preferred fuel for the cells lining the colon. They provide energy and support gut health by serving as a fuel source for these cells. Long-chain fatty acids are not the preferred fuel for colon cells as they are harder to digest and absorb in this part of the digestive system. Amino acids are the building blocks of proteins and not the primary energy source for colon cells. Glucose is the main energy source for most cells in the body, but colon cells prefer short-chain fatty acids.

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