Chlorophyll the last step, the conversion of protochlorophyllide to chlorophyll, is light-dependent and such plants are pale (etiolated) if grown in darkness. Non-vascular plants and green algae have an additional light-independent enzyme and grow green even in darkness. Chlorophyll itself is bound to proteins and can transfer the absorbed energy in the required direction. Protochlorophyllide occurs mostly in the free form and, under light conditions, acts as a photosensitizer, forming highly toxic free radicals. Hence, plants need an efficient mechanism of regulating the amount of chlorophyll precursor. In angiosperms, this is done at the step of aminolevulinic acid (ALA), one of
Chlorophyll a electron transport chain. These two systems are different in their redox potentials for one-electron oxidation. The E for P700 is approximately 500mV, while the E for P680 is approximately 1,100-1,200 mV. Chlorophyll "a" is very important in the energy phase of photosynthesis. Two electrons need to be passed to an electron acceptor for the process of photosynthesis to proceed. Within the reaction centers of both photosystems there are a pair of chlorophyll "a" molecules that pass electrons on to the transport chain through redox reactions. Chlorophyll a Chlorophyll "a" is a specific form of chlorophyll used in oxygenic photosynthesis. It