External manifestation of plate-like particle arrays in the plasma membrane of Tetrahymena.

Plate-like arrays of 3-4 nm particles were previously reported to occur on the P face of the plasma membrane of Tetrahymena. Surface replicas have now been prepared from frozen, deep-etched cells. These replicas demonstrate that plate-like arrays are manifested on the external surface of the plasma membrane. This observation lends support to the idea that the plate-like arrays have a receptor function related either to feeding or to mating behavior in Tetrahymena.