Photosynthetic membranes and Organelles.

http://en.wikipedia.org/wiki/Photosynthesis

In photosynthetic bacteria, the proteins that gather light for photosynthesis are embedded within cell membranes, which is the simplest configuration these proteins are arranged.However, this membrane may be tightly folded into cylindrical sheets called thylakoids,or bunched up into round vesicles called intracytoplasmic membranes.These structures can fill most of the interior of a cell, giving the membrane a very large surface area and therefore increasing the amount of light that the bacteria can absorb.

In plants and algae, photosynthesis takes place in organelles called chloroplasts. A typical plant cell contains about 10 to 100 chloroplasts. The chloroplast is enclosed by a membrane. This membrane is composed of a phospholipid inner membrane, a phospholipid outer membrane, and an intermembrane space between them. Within the membrane is an aqueous fluid called the stroma. The stroma contains stacks (grana) of thylakoids, which are the site of photosynthesis. The thylakoids are flattened disks, bounded by a membrane with a lumen or thylakoid space within it. The site of photosynthesis is the thylakoid membrane, which contains integral and peripheral membrane protein complexes, including the pigments that absorb light energy, which form the photosystems.