The origin of replication (also called the replication origin) is a particular sequence in a genome at which replication is initiated.
It is the interaction of two or more substances, resulting in chemical changes in them. Chemical reactions take place when some kind of energy is supplied to them. The supplied energy may be in the form of heat, light or mechanical shaking for proper contact between the reactant molecules or electricity.
In an adiabatic system (i.e. a system that does not exchange heat with the surroundings), an exothermic process results in an increase in temperature of the system. In exothermic chemical reactions, the heat that is released by the reaction takes the form of electromagnetic energy. The transition of electrons from one quantum energy level to another causes light to be released.