Practice question

GITC (guanidinium isothiocyanate) is a powerful chaotropic agent used in RNA isolation methods like TRIzol. It simultaneously lyses cells, denatures proteins, and inactivates RNases instantly by disrupting hydrogen bonding and hydrophobic interactions, unfolding secondary structures. RNases are extremely resilient and require strong denaturants; GITC at 4 M denatures them irreversibly, protecting RNA from degradation. It does not primarily digest proteins enzymatically, inhibit DNases selectively, or solubilize lipids only. Combined with phenol, it allows partitioning of intact RNA into aqueous phase with high integrity.