AP BIOLOGY

Detailed explanation-1: -The chlorophyll a special pairs of the two photosystems absorb different wavelengths of light. The PSII special pair absorbs best at 680 nm, while the PSI special absorbs best at 700 nm. Because of this, the special pairs are called P680 and P700, respectively.

Detailed explanation-2: -The reaction center of photosystem II which best absorbs light at a 680 nm wavelength. P-680 is a chlorophyll a molecule.

Detailed explanation-3: -Blue (420-450nm) and Red (620-680nm): Chlorophyll b molecule has a similar structure to that of chlorophyll a. It absorbs mostly 453nm and 642 nm wavelength light, Although Chlorophyll b is not as abundant as chlorophyll a, it helps the range of light a plant can use for energy.

Detailed explanation-4: -P680 is the reaction centre of photosystem II, which consists of chlorophyll a molecules with an absorption maximum at the wavelength of 680nm, or it absorbs the 680nm wavelengths the best.

Detailed explanation-5: -It is clear that plant chlorophylls absorb mainly in blue (between 400 and 500 nm) and red (around 650 to 680 nm). Plants also contain carotenoids such as -carotene and lutein, which absorb somewhat to the red of the main chlorophyll b transition at 460 nm.