how many quanta of lights are required to evolve one oxygen molecule in photosythesis?

1. threee
2. eight
3. four
4. two

a total of 8 photons are required for one oxygen molecule.
In thelight reactions, one molecule of thepigmentchlorophyllabsorbs onephotonand loses one electron. This electron is passed to a modified form of chlorophyll calledpheophytin, which passes the electron to aquinonemolecule, allowing the start of a flow of electrons down anelectron transport chainthat leads to the ultimate reduction ofNADPtoNADPH. In addition, this creates a proton gradientacross thechloroplast membrane; its dissipation is used byATP synthasefor the concomitant synthesis ofATP. The chlorophyll molecule regains the lost electron from awater molecule through a process calledphotolysis, which releases adioxygen(O2) molecule. The overall equation for the light-dependent reactions under the conditions of non-cyclic electron flow in green plants is:
2 H2O + 2 NADP++ 3 ADP + 3 Pi+ light → 2 NADPH + 2 H++ 3 ATP + O2
Not allwavelengthsof light can support photosynthesis. The photosynthetic action spectrum depends on the type ofaccessory pigmentspresent. For example, in green plants, theaction spectrum resembles theabsorption spectrumforchlorophyllsandcarotenoidswith peaks for violet-blue and red light. In red algae, the action spectrum overlaps with the absorption spectrum ofphycobilinsfor red blue-green light, which allows these algae to grow in deeper waters that filter out the longer wavelengths used by green plants. The non-absorbed part of thelight spectrumis what gives photosynthetic organisms their color (e.g., green plants, red algae, purple bacteria) and is the least effective for photosynthesis in the respective organisms.