Excess amounts of most water-soluble vitamins are excreted by the a. kidneys. b. intestine. c. skin. d. lungs.
Which of the following helps make collagen? a. Niacin b. Pantothenic Acid c. Riboflavin d. Vitamin C
The Correct Answer and Explanation is:
Correct Answers:
- Excess amounts of most water-soluble vitamins are excreted by the:
a. kidneys. - Which of the following helps make collagen?
d. Vitamin C
Explanation
Water-soluble vitamins include the B-complex group (e.g., B1, B2, B3, B6, B12, folate) and vitamin C. Unlike fat-soluble vitamins, water-soluble vitamins are not stored in significant amounts in the body. Once the body absorbs what it needs, the excess is filtered out and excreted through the kidneys, making option a correct for the first question. This excretion occurs via urine, which is why deficiencies can develop more rapidly if dietary intake is insufficient. The kidneys play a central role in maintaining the balance of water-soluble vitamins, and they also help regulate electrolyte and fluid balance in the body.
In the second question, Vitamin C (ascorbic acid) is essential for collagen synthesis, making option d the correct answer. Collagen is a structural protein found in skin, bones, tendons, and connective tissues. Vitamin C acts as a coenzyme in the hydroxylation of proline and lysine—two amino acids vital for stabilizing the collagen molecule. Without adequate vitamin C, collagen production is impaired, leading to weakened connective tissue and symptoms like bleeding gums, bruising, and poor wound healing—a condition known as scurvy.
The other options listed—niacin, pantothenic acid, and riboflavin—are important B vitamins with various roles in metabolism but do not directly contribute to collagen synthesis. Niacin (B3) supports energy metabolism and DNA repair, pantothenic acid (B5) is involved in coenzyme A production, and riboflavin (B2) is crucial for redox reactions in energy production. While all these are essential for overall health, they do not directly aid in collagen formation as Vitamin C does.
Thus, understanding the specific roles of vitamins helps explain their unique contributions to human physiology and the importance of a balanced diet for maintaining health.
