Definitions

Proteoglycans are large molecules found in the extracellular matrix and on the cell surface. They consist of a core protein that long chains of sugar molecules called glycosaminoglycans (GAG) are attached. Proteoglycans play essential roles in various biological processes, including cell signaling, adhesion, and tissue organization. They are particularly present in connective tissues, where they contribute to the structure and provide resistance to compression.

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Hydroxyproline is a major component of collagen, a primary structural protein found in connective tissues, skin, and bones. The hydroxylation of proline to form hydroxyproline is crucial for the stability of collagen's triple helix structure, as it enables the formation of hydrogen bonds that keep the collagen fibers tightly bound together. This process is dependent on vitamin C, which is why vitamin C deficiency can lead to impaired collagen synthesis.

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 Hemidesmosomes are specialized cell-matrix adhesion structures found in epithelial cells. They are responsible for anchoring the basal surface of the epithelial cells to the underlying basement membrane, providing mechanical stability and maintaining tissue integrity. Hemidesmosomes are particularly important in tissues that experience significant mechanical stress, such as the skin and mucous membranes.

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