Practice question

Cryo-electron microscopy avoids chemical fixation artifacts by vitrifying hydrated biomolecules in thin aqueous film plunged rapidly into liquid ethane at -180°C. Ultra-fast cooling prevents crystalline ice formation, instead embedding particles in amorphous transparent ice that preserves near-native conformation and hydration. Imaging under low dose at cryogenic temperature maintains structural integrity during electron exposure. No staining with uranyl acetate, resin embedding, or dehydration needed. Vitrification locks dynamic states, enabling high-resolution structure determination of proteins, viruses, and molecular machines in physiologically relevant forms.