ABSTRACT
This chapter briefly discusses photosynthesis, which is the most vital bioenergy-generating process, without which life on earth and the existence of our biosphere would be impossible. Duysens and his team demonstrated the involvement of two photosystems in the light phase of photosynthesis: Photosystem I (PSI) and Photosystem II (PSII), which contain pigments and numerous proteins. Typically, chloroplasts contain more PSII than PSI, and the stoichiometric ratio of the amount of PSII to PSI is often around 1.5, but it can vary subject to the environmental conditions. The major pigments participating in photosynthesis are chlorophylls, which give plants their green color. In addition to chlorophylls, thylakoid membranes also contain other auxiliary pigments like carotenoids and phycobilins. Thylakoid membranes are where the light phase of photosynthesis occurs, while the stroma contains enzymes essential for the dark phase of photosynthesis. The absorbed photosynthetically active radiation (PAR) is used for the synthesis of adenosine triphosphate (ATP) and Nicotinamide adenine dinucleotide phosphate (NADPH).
