A 9-month-old infant is seen by her pediatrician, who notices a lack of weight gain as well as thin, knobby joints. The parents tell the physician that they are making their own baby food and that their daughter has been very irritable and cries a lot when she is crawling on the floor. The baby's gums appear to be overly red. The pediatrician suspects lack of vitamin C in the baby's diet and recommends that the parents switch to commercially prepared baby foods and also urges them to offer the child citrus fruits. Additionally, the child is to receive high doses of vitamin C for 7 days and a lower dose for an additional 30 days. Vitamin C is necessary for the synthesis of normal

Question

Quizplus · Accepted Answer

Vitamin C is necessary for the synthesis of tropocollagen, which is a precursor to collagen, the main structural protein in the body. Lack of vitamin C can result in weakened collagen and connective tissue, leading to symptoms such as joint pain and red, swollen gums. Elastin and fibrillin are also connective tissue proteins, but they are not directly synthesized from tropocollagen and are not affected by vitamin C deficiency to the same extent. Troponin is a protein involved in muscle contraction and hyaluronic acid is a type of carbohydrate found in connective tissue, but neither are directly synthesized from tropocollagen or affected by vitamin C deficiency.

A 9-Month-Old Infant Is Seen by Her Pediatrician, Who Notices