Collagen and Elastin — Flashcards

Flashcard 1: Formation of lysine-hydroxylysine cross-linkages (collagen synthesis) requires both _____ and the enzyme lysyl oxidase

Answer: copper

Flashcard 2: Which two glycosaminoglycans (GAGs) play a role in corneal transparency?

Answer: Keratan sulfate and dermatan sulfate

Flashcard 3: Collagen Synthesis: Once in the extracellular space, cleavage of disulfide-rich terminal regions of procollagen by _____ forms the insoluble tropocollagen

Answer: procollagen peptidase

Flashcard 4: Elastin is rich in non-hydroxylated _____, glycine, and lysine residues (amino acids)

Answer: proline

Flashcard 5: Collagen Synthesis: Staggered tropocollagen molecules are reinforced by covalent _____ cross-linkages to make collagen fibrils

Answer: lysine-hydroxylysine

Flashcard 6: Curve A indicates which compound? _____

Answer: Myoglobin

Flashcard 7: The given image represents a _____ which is a secondary structure of proteins.

Answer: beta-sheet

Flashcard 8: egg white forms _____% weight of egg

Answer: 60

Extra: 

Flashcard 9: Serum _____ is the most sensitive indicator for protein estimation (nutritional status).

Answer: pre-albumin

Extra: • **Pre-albumin (Transthyretin):** Most sensitive indicator (Half-life ≈ 2 days). • **Albumin:** Indicator of chronic nutritional status (Half-life ≈ 20 days). • **Retinol-binding protein:** Even shorter half-life (~12 hours) but less commonly tested. Note: Albumin is a negative acute-phase reactant, meaning its levels drop during inflammation regardless of nutritional status.