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
Transduction (biophysics) called "resonant-energy-transferring" molecules of the chlorophyll class, which transfer what is considered electromagnetic energy, from one to its neighbor with no participation of electrons nor enzymes. At this stage, if the first pigment has received an excess of light, the "exciton" perhaps might "dissipate" the energy as heat. Transduction (biophysics) In biophysics, transduction is the conveyance of energy from one electron (a donor) to another (a receptor), at the same time that the class of energy changes. Photonic energy, the kinetic energy of a photon, may follow the following paths: In photosynthesis, when the electrons of the "chlorophyll pair" receive