Biological Oscillators and Switches

Although living biological systems are immensely complex, they are at the same time highly ordered and compactly put together in a remarkably efficient way. Such systems concisely store the information and means of generating the mechanisms required for repetitive cellular reproduction, organisation, control and so on. To see how efficient they can be you need only compare the information storage efficiency per weight of the most advanced computer chip with, say, the ribonucleic acid molecule (mRNA) or a host of others: we are talking here of factors of the order of billions. This chapter, and the next two, are mainly concerned with oscillatory processes. In the biomedical sciences these are common, appear in widely varying contexts and can have periods from a few seconds to hours to days and even weeks. We consider some in detail in this chapter, but mention here a few others from the large number of areas of current research involving biological oscillators.