Found on chromosome ends, they become shorter due to chemical instability and replication errors as cells divide.  
Bacteria have circular genomes and don't need them.  Identified in the 1970s, these structures are multiple copies of short DNA sequences. Found on chromosome ends, they become shorter due to chemical instability and replication errors as cells divide.  For ten points, name these cellular structures which hold important clues for research into cancer and aging.
Bacteria have circular genomes and don't need them.  Identified in the 1970s, these structures are multiple copies of short DNA sequences.
telomeres (do not accept telomerase)