The cell reproduction processes require terabytes of chromosome DNA information to be copied every second within the body. Besides, the protein formation and other functions in cells can be several orders of magnitude more information-intensive. The brain consists of interconnected neurons which exchange signals with each other and with the rest of the body cells. There are at least three different signaling mechanisms. Those signals can either be received directly as ion current arriving to a receiving neuron's dendrite or through a more complicated neurotransmitter mechanism.
Some neurons can also produce or receive special chemical tags transported though the blood flow.
The total information processing activity of the brain is hard to estimate because the current knowledge in this area is fragmentary. However, it is possible to get a general picture of the electronic pulse exchange activity within a couple of orders of magnitude. The activity of the brain is equivalent to that of 1000 kHz processor with 40 Gbits of states. If we assume that brain only needs the energy to perform the computations, the efficiency is about 10 -8 of the physical limit. The neurons require several orders of magnitude more power than the other cells.