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.
When light energy is passed by chlorophyll molecules to the center of photosystem II (the first photosystem in the chain), it energizes a central chlorophyll molecule called P680. This molecule is so energized that it is passed along another chain to photosystem I.