Origins of mitochondria and chloroplast Both mitochondria and chloroplast have an inner and outer membrane, each a phospholipid bilayer with a unique collection of embedded proteins. The inner membrane of the mitochondria is convoluted, with infoldings called cristae which gives it a greater surface are to enhance productivity of cellular respiration, it also encloses the mitochondrial matrix, and contains built in enzymes that make ATP. The inner membrane of the chloroplast encloses the granum structures …showed first 75 words of 1260 total…

…showed last 75 words of 1260 total…bacteria. In considering the origin of eukaryotes, we must understand that the endosymbiotic model is not mutually exclusive. Possibly, the chloroplast and mitochondria may have originated as endosymbionts. In addition, the endosymbiotic model doesn't require an event leading to greater cellular complexity to happen just once in the course of evolution. Comparison of algal pigments and chloroplast construction suggests that, by whatever mechanism, photosynthetic protists likely evolved at least three times from separate prokaryotic ancestors.