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.
Endothermic reactions take in heat from the surroundings (and make it cooler), exothermic reactions give out heat to the surroundings making it hotter. Get too close to a sparâ¦kler and you'll find it is very hot! This is because it is an exothermic reaction.