These two elements are transposase and terminal repeats. Transposase enzyme binds to the end of a transposon and catalyzes the movement of the transposon to another part of the genome by a cut and paste mechanism or replicative transposition mechanism. Terminal repeats are identical sequences which repeats hundreds or thousands of times, found at the end of proviral DNA formed by reverse transcription of retroviral RNA. They are used by viruses to insert genetic material into the host genomes.