Practice question

Cryo-EM determines structures without crystallization, a major advantage over X-ray crystallography requiring well-ordered crystals often unattainable for membrane proteins and large complexes. Instead, purified particles are vitrified in thin ice, imaged individually, and computationally averaged to achieve near-atomic resolution. Crystallization can force non-native conformations and fails for heterogeneous samples. Cryo-EM preserves conformational diversity, allowing classification of distinct states. While bright field light microscopy also avoids crystallization, it lacks molecular resolution. Thus cryo-EM revolutionized structural biology by bypassing crystal bottleneck entirely.