That enzyme, a reverse transcriptase, lengthens the strand before replication, allowing cells to compensate for their shortening during DNA replication.  
Their namesake enzyme is generally found in unicellular eukaryotes and the cells of the germline, including embryonic stem cells.  That enzyme, a reverse transcriptase, lengthens the strand before replication, allowing cells to compensate for their shortening during DNA replication.  They possess sequences of a rich G-strand and a rich C-strand and almost all are found to have the TTAGGG simple sequence repeat.  FTP, name these structures associated with aging, the physical ends of linear eukaryotic chromosomes.
Their namesake enzyme is generally found in unicellular eukaryotes and the cells of the germline, including embryonic stem cells.  
telomeres