Question

PS I first wavelength / reaction center is:

• A. Chl–680
• B. Chl–700
• C. Chl–660
• D. Chl–760

Hint:

Remember: PS I = P700, PS II = P680. The number corresponds to the wavelength (in nm) of light best absorbed by their reaction centers.

Answer 1

The Correct Option is B

Photosystem I (PS I) is one of the two major protein-pigment complexes involved in the light reactions of photosynthesis. It plays a crucial role in converting light energy into chemical energy. The reaction center of PS I is specifically associated with a special form of chlorophyll a that absorbs light most efficiently at a wavelength of 700 nm, hence it is called P700 (where "P" stands for pigment and "700" indicates the peak absorption in nanometers).
This reaction center is responsible for transferring high-energy electrons to the electron transport chain, which ultimately contributes to the synthesis of NADPH. This distinguishes it from Photosystem II (PS II), which has a reaction center at 680 nm (P680). Options like Chl–660 and Chl–760 are incorrect as these wavelengths do not correspond to the peak absorption of any major photosystem's reaction center.