Which of the Following Matrix Molecules in Cartilage Tends to Trap

Question

Which of the following matrix molecules in cartilage tends to trap large quantities of water?
A) proteoglycan
B) hyaluronic acid
C) elastin
D) collagen
E) chondrocytes

Accepted Answer

Proteoglycan is the matrix molecule in cartilage that tends to trap large quantities of water due to its structure, which features long chains of glycosaminoglycans (GAGs) attached to a protein core. The negative charges on the GAGs attract water molecules, leading to the ability of cartilage to resist compression and provide shock absorption. Hyaluronic acid is also a GAG that contributes to the hydration of cartilage, but it is not a matrix molecule in cartilage as it is found in synovial fluid. Elastin and collagen are structural proteins in the extracellular matrix of cartilage but they do not have the same capacity to trap water as proteoglycans. Chondrocytes are cells that produce and maintain the cartilage matrix but they are not a matrix molecule themselves.