Question

If an oxygenic phototroph (such as a marine cyanobacterium) has sufficient quantities of ________, cyclic flow of electrons back to the ________ reaction center can provide energy for the generation of _________ instead.

Answer 1

Answer:

-NADPH; PSI; ATP

Explanation:

Photosynthesis can be defined as a series of chemical reactions where light energy is converted into redox energy which is used to produce different metabolic reactions. The plastocyanin-ferredoxin oxidoreductase (also known as Photosystem I or PSI) is one of the two photosystems present in cyanobacteria, algae and plants that use light energy in order to produce ATP and NADPH. The molecules of chlorophyll in PSI and PSII absorb energy from the light and it triggers the transference of electrons to other molecules. Both PSI and PSII can move electrons from water to Nicotinamide adenine dinucleotide phosphate (NADP+) and thus generate NADPH. Moreover, PSI can also recycle electrons by generating an H+ gradient that allows to synthesize ATP but no NADPH.