In vitro research is generally referred to as the manipulation of organs, tissues, cells, and biomolecules in a controlled, artificial environment. The characterization and analysis of biomolecules and biological systems in the context of intact organisms is known as in vivo research.

The basic unit of living organisms is the cell, which in terms of scale and dimension is at the interface between the molecular and the microscopic level. The living cell is in turn divided into functional and structural domains such as the nucleus, the cytoplasm, and the secretory pathway, which are composed of a vast array of biomolecules. These molecules of life carry out the chemical reactions that enable a cell to interact with its environment, use and store energy, reproduce, and grow. The structure of each biomolecule and its subcellular localization determines in which chemical...