Biochemistry is closely related to molecular biology, the study of the molecular mechanisms by which genetic information encoded in DNA is able to result in the processes of life. Depending on the exact definition of the terms used, molecular biology can be thought of as a branch of biochemistry, or biochemistry as a tool with which to investigate and study molecular biology. Biochemistry is one of the few basic sciences where animal and plant kingdoms meet. Biotechnology is the technical applications of biological systems for the production of natural substances (biogas, antibiotics, enzymes organic acids etc) it involves the use of living organisms deliberately to carry out defined chemical processes and exploitation of biological processes for man’s use. Modern biotechnology is hinged on the tools of recombinant technology also called gene manipulation or genetic engineering. This book will serve as a handy material for the students as well as teachers, taking undergraduate and postgraduate courses in Veterinary sciences, Biological sciences, Genetics, Microbiology, Molecular Biology, Biotechnology and allied subjects.