A model for the topological organization of the chloroplast thylakoid membr
ane is presented. A series of illustrations is provided, which outline a su
ggested 3-dimensional structure in cross-section and in full shape, which a
ccounts both for the folding of one continuous membrane into multiple grana
stacks as seen in cross-sectional electron micrographs and for the rapid r
eversible unfolding (destacking) of the grana stacks into lamellar sheets.