Photosynthetic Unit (Quantasome)
Photosynthetic unit can be defines as number of pigment molecules required to affect a photochemical act, that is the release of a molecule of oxygen. Emerson and Arnold (1932) told that the umber of chlorophyll molecules required is 2500. According to Niggins (1964), only 230 chlorophyll molecules are needed. They further noticed distinct morphological structures on thylakoid membranes and identified them as quantasomes. So quantasomes can be defined as morphological expressions of photosynthetic units.
More information on quantasome
A quantasome is…
A particle that is embedded in a paracrystalline array on the surface of thylakoid discs in chloroplasts. Quantasomes are composed equally of lipids and proteins, which include various photosynthetic pigments and redox carriers. For this reason they are considered to be photosynthetic units. They occur in 2 sizes: the smaller quantasome is thought to represent the site of photosystem I, the larger to represent the site of photosystem II.