Elementary plant Biochemistry and Biotechnology (2+1)

Introduction

• Genetic information is transferred from parent to progeny organisms by a faithful replication of the parental DNA molecules.
  
• At the biochemical level, replication is defined as a template-directed nucleic acid synthesis reaction where the template and nascent (growing) strand are the same type of nucleic acid.
  
• Replication is a polymerization reaction and can be divided into stages of initiation, elongation and termination.


• Replication of dsDNA is a complicated process that is not completely understood due to the following facts:
1. A supply of energy is required to unwind the helix
2. The single strands resulting from the unwinding tend to form intrastrand base pairs
3. A single enzyme can catalyze only a limited number of physical and chemical reactions and many reactions are needed in replication.
4. Several safeguards have evolved that are designed both to prevent replication errors and to eliminate the rare errors that do occur
5. Both circularity and the enormous size of the DNA molecules impose geometric constraints on the replicative system and how this fit into the system has to be understood.