Photosynthesis 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. Enclosed by the membrane is an aqueous fluid called the stroma. Embedded within the stroma are stacks of thylakoids (grana), which are the site of photosynthesis. The thylakoids appear as flattened disks. The thylakoid itself is enclosed by the thylakoid membrane, and within the enclosed volume is a lumen or thylakoid space. Embedded in the thylakoid membrane are
Fractionation of carbon isotopes in oxygenic photosynthesis product 3-phosphoglycerate is depleted in C due to the kinetic isotope effect of the above reaction. The overall C fractionation for C3 photosynthesis ranges between -20 to -37‰. The wide range of variation in delta values expressed in C3 plants is modulated by the stomatal conductance, or the rate of CO entering, or water vapor exiting, the small pores in the epidermis of a leaf. The δC of C3 plants depends on the relationship between stomatal conductance and photosynthetic rate, which is a good proxy of water use efficiency in the leaf. C3 plants with high water-use efficiency tend to