Final answer:
Telomeres are needed to allow DNA replication at the ends of linear chromosomes in order to prevent the loss of important gene sequences. Telomeres have repetitive sequences that protect the chromosomes, and telomerase enzyme helps in their maintenance.
Step-by-step explanation:
The telomeres, which are repetitive sequences at the ends of linear chromosomes, are essential for allowing DNA replication to occur at the ends of chromosomes. Eukaryotic DNA polymerase can only add nucleotides in the 5' to 3' direction, and on the lagging strand, there is no place for a primer to be made for the DNA fragment at the end of the chromosome. This results in the ends of the chromosomes remaining unpaired and getting progressively shorter with each round of DNA replication. Telomeres, with their repetitive sequences, provide a protective cap at the ends of chromosomes and prevent the loss of important gene sequences during DNA replication.