Protein Structure and Function — Flashcards

Flashcard 61: Biuret reaction is used to check for _____ linkages

Answer: Peptide (or peptide bonds)

Extra: The Biuret test is used to detect **peptide bonds**. **Note:** A positive result requires at least **two peptide bonds**. Therefore, the test is positive for polypeptides and proteins, but **negative** for free amino acids and dipeptides (which only have one peptide bond).

Flashcard 62: _____ is the most reliable marker for cellular autophagy

Answer: Microtubule-associated protein light chain 3 (LC3)

Flashcard 63: Aromatic amino acids such as tyrosine, tryptophan, and phenylalanine absorb _____ nm UV light.

Answer: 250 to 290

Flashcard 64: 11-cis-retinal (a chromophore) is covalently bound to opsins via a _____ residue on one of the transmembrane domains.

Answer: lysine

Flashcard 65: What is the stabilizing bond in secondary protein structure?

Answer: Hydrogen bonds

Flashcard 66: Free beta- and gamma-chains are _____ soluble than free alpha-chains.

Answer: More

Flashcard 67: Which two glycosaminoglycans (GAGs) play a role in corneal transparency?

Answer: Keratan sulfate and dermatan sulfate

Flashcard 68: What is the predominant whey protein in cow milk?_____

Answer: Beta-lactoglobulin

Flashcard 69: What is the stabilizing bond in tertiary protein structure?_____

Answer: Hydrophobic bond>Hydrogen bond>Ionic bond

Flashcard 70: GAGs maybe attached to a protein molecule to form a _____

Answer: proteoglycan