ABSTRACT
Recent advances in molecular biology have provided us with powerful experimental tools for studying individual processes at the molecular and cellular levels. However, the complexity of biological behavior is the result of dynamic interactions occurring not only among the various components of a cell, but also among the populations of cells that form human tissues. As shown schematically in Figure 26.1, biological processes and interactions occur across a 109 range of spatial scales: from the nanometer scale at the molecular level to the meter scale at the human tissue and organ system level. e time scales encountered are even broader. Molecular interactions occur at the 10−9 or 10−6 scale, whereas human life spans a period of 109 s. An impressive array of experimental techniques has been developed to acquire data across the spectrum of spatial scales: from protein biochemistry and other proteomic techniques at the molecular level, to sophisticated microscopy techniques at the cell level and magnetic resonance imaging or computed tomography diagnostic imaging at the human level.
