Isolated chloroplasts of the unicellular photosynthetic alga Chlamydomonas reinhardtii were cryofixed, freeze-fractured, and surface replicas observed by transmission electron microscopy. This close-up of wildtype thylakoids shows the particle size and distribution characteristic of 'C' fracture planes where the thylakoids are unstacked. See Fig 8 in Goodenough and Staehelin 1971 J Cell Biol 48:595-619.
Isolated chloroplasts were cryoprotected with glycerol, cryofixed, fractured at -100C, shadowed with Pt, and replicas prepared by carbon coating. Cleaned replicas were examined with a Philips 300 TEM. See Goodenough and Staehelin 1971 J Cell Biol 48:595-619