Question

Name the reaction centres of PS I and PS II.

Answer 1

The group of pigment molecules which take part in the conversion of light energy into the chemical energy is known as the photosynthetic unit. Photosystem I (PS I) and Photosystem II (PS II) are the two types of photosynthetic units. Each unit has a reaction centre of a specific chlorophyll a molecule which absorbs light energy of long wavelength. This reaction centre is also known as photocentre. These centers can release electron upon absorption of energy. In PS I, the reaction centre chlorophyll a has an absorption peak at 700 nm, hence is called $P_{700}$, while in PS II, reaction centre has an absorption peak at 680 nm and is called $P_{680}$.