Biogenesis of Chloroplast Membranes

The apparent buoyant density of the photosynthetic membranes was measured at different stages of their formation during the greening of dark-grown Chlamydomonas reinhardi y-l cells.Changes in the banding position of membranes in Urografin density gradients between 1.120 g per cm3 to 1.140 g per cm3 could be correlated with increase in photosynthetic activity and with synthesis of specific membrane proteins in the chloroplast.Increase in density was observed during the initial phase of the greening process as well as during repair of nonphotosynthetic membranes formed in the presence of chloramphenicol.However, no correlation could be found between the later phenomenon and synthesis of specit%z lipids.