The current book aims to provide the complete curriculum for Biotechnology Undergraduate students. The first chapter has genetics of cell and its biology like cell theory, cell structure, organization, linkages, gene mapping, chromosome structure and organization of chromatin, hereditary defects, inheritance, Hardy-Weinberg law. The chapter second, the molecular biology and genetic engineering has been discussed viz. nucleic acids as genetic material, structure of A, B and ZDNA, palindromic sequences, structure of RNA (t-RNA, m-RNA and r-RNA), DNA denaturation and renaturation, DNA replication in prokaryotes, DNA polymerase I, II and III, modes and mechanism of DNA replication, DNA repair mechanisms, Transcription in prokaryotes, RNA polymerase, types and functions of RNA polymerases in eukaryotes, Genetic code, translation in prokaryotes, Post-translational modifications, Gene organization, Operon concept and introduction to gene regulation mechanisms, Transposons, Basic concept of recombinant DNA technology, principles of gene cloning, Restriction modification systems, use of restriction enzymes in biotechnology, cloning vectors, methods of gene transfer, DNA libraries, Introduction to PCR, RFLP, DNA sequencing, blotting techniques. In the last chapter, animal tissue culture and plant tissue culture techniques has been elaborated along with monoclonal antibodies and secondary metabolites. The book will help teachers, students and researchers of biotechnology.