The linear mass density can then be understood as the derivative of the mass function with respect to the one dimension of the rod (the position along its length =) The SI unit of linear mass density is the kilogram per meter (kg/m). Linear density of fibers and yarns can be measured by many methods.
An Arabidopsis thaliana chlorophyll(ide) a oxygenase gene (cao), which is responsible for chlorophyll b synthesis from chlorophyll a, was introduced and expressed in a photosystem I-less strain of the cyanobacterium Synechocystis sp.
The photosystem I was named I since it was discovered before photosystem II, but this does not represent the order of the electron flow. When photosystem II absorbs light, electrons in the reaction-center chlorophyll are excited to a higher energy level and are trapped by the primary electron acceptors.