How cells are studied

We learnt about the evolution of the cell and a historical account of the growth of cell biology. In this section, you will study about the various tools and techniques used to study the cell.

Cells, due to their minute size, cannot be observed by the naked eye. Lenses can magnify minute objects only upto a limited extent. Therefore, many lenses were combined together to form an instrument known as the microscope (Gr mikros-small, skopein-to see). Subsequently, many new tools and techniques were invented by cell biologists about which you will study in detail in this section.

We begin the section with light microscope (LM). Here, you will know about the difference between resolving power and magnification and various cytochemical techniques which are used to study the chemical components and structural organisation of the cell. Phase contrast microscopy; an important technique for viewing the live cells is described. You will also learn about electron microscopy (EM), the best known method for the study of the ultrastructure of the cell and an important technique called 'freeze fracturing' which is used to study the internal structure of membrane in the cell.

Use of radioisotopes, antibodies, and fluorescence microscopy for localisation of various cell components are discussed in this Unit. You will also learn about cell culture and cinemicrography, the other important techniques used to study live cells. While going through this unit, it would be useful to recall and apply your knowledge of elementary chemistry, physics and mathematics, such as radioisotopes, refractive index and simple mathematical calculations. The study of this Unit assumes that you are familiar with the optical laws and princi~leso n which a microscope works.