Table 1. Comparison of in extracto cryogenic electron microscopy (cryo-EM) with traditional in vitro and in situ cryogenic electron tomography (cryo-ET) approaches to structural biology.

Cryo-EM method Features	In vitro (traditional single particle)	In extracto (this work)	In situ (e.g. cryo-ET)
Interactions with cellular components	– *	+/–	+
Purified macromolecules	+	+/– (can be added)	–
Time-resolved cryo-EM	+	+	–
Fast sample and grid preparation, and data collection to enable near-atomic resolution	+ (hours to an overnight session)	+ (1–3 overnight sessions)	– (days/weeks)
Efficient particle identification (low # of false positives)	+	+	+/–

*+ Means straightforward, – difficult/impossible, +/– possible.