Height levels associated with grana membranes. A, Topography image at intermediate resolution of two membrane fragments from grana membrane preparations with three different height levels. B, Deflection image of A. C, Three membrane height profiles (profiles 1, 2, and 3) from the topography image of A. Note that the height is measured with respect to the mica surface. D to F, Graphs showing percentage distributions of particle maximum vertical heights from membranes with height levels 1 (D), 2 (E), and 3 (F), with respect to the reference mica height. For statistics, see Supplemental Table S1.