 Dear students, welcome to the course Bio 302, which is entitled as Molecular Biology. Molecular biology is relatively a new field in biotechnology and it has more than one definitions. So in the broader terms, definition of molecular biology includes all aspects of the study of life from the molecular perspective. Or in other words, we can say molecular biology attempts to describe the phenomena of life in the molecular terms. So if we define molecular biology in this way, we cannot distinguish it from a well-known discipline biochemistry because the definition of biochemistry is also same. Biochemistry also attempts to describe the phenomena of life in molecular terms. So if we define molecular biology more precisely, the term molecular biology refers to the biology of the molecules related to genes, gene products and heredity. So in other words, we can also say molecular biology attempts to describe the structure and functions of genes. Still in other ways, we can also define molecular biology as a field of biology which describes the storage, expression and transmission of genetic information in molecular terms. So in other words, the term molecular biology is often substituted for a more appropriate term, which is called molecular genetics because it is a union of genetics and biochemistry or molecular biology. So molecular biology grew out of the disciplines of genetics and biochemistry. These two main fields contributed towards the emergence of molecular biology. However, some scientists are of the view that cell biology and microbiology also contributed towards the development of molecular biology. In the present age, world is in the midst of two scientific revolutions. One is in the field of information technology and the other one is in the field of molecular biology. Both of these fields, that is molecular biology or information technology both deal with the handling of large amount of information. In case of information technology, the information is man-made. While in case of molecular biology, the information is natural. So molecular biology has revolutionized the biological sciences as well, especially in the fields of health sciences and agricultural sciences. So these two fields, health sciences and agricultural sciences are most affected after the emergence of molecular biology. For example, if we say health sciences, in 2003, complete human genome has been sequenced and a lot of information is available. So theoretically we can say molecular biology has made it made it possible to make a complete human information having information from the human genome project. The other main arena is the agricultural sciences. A number of new varieties of both the animals and plants have been created with the help of molecular biology and some are in use and some are in the trials. So it has affected our lives. So you can well imagine how much this subject is important for you as well as for the economy of Pakistan.