Question

In PS I, the reaction centre Chl a has absorption maxima at ________; whereas in PS II, the reaction centre Chl a has absorption maxima at _________.

• A. 700 nm, 680nm
• B. 680 nm, 700nm
• C. 400 nm, 500 nm
• D. 700 nm, 800 nm

Answer 1

The correct option is A 700 nm, 680nm

The reaction center of photosystem I (PSI) is referred to as $P_{700}$ where "P" stands for "Pigment" and "700" stands for the wavelength of light that this particular chlorophyll molecule absorbs most strongly. The reaction center of photosystem II (PS II) is referred to as $P_{680}$ for comparable reasons.