Final answer:
Each round of cell division results in the progressive shortening of chromosomes because the ends, or telomeres, lose a small amount of DNA and cannot be fully replicated by DNA polymerases.
Step-by-step explanation:
If cells cannot replicate the ends of their DNA, with each round of cell division, the chromosome should get shorter. This shortening occurs because DNA polymerases, which replicate DNA, cannot fully replicate the very ends of chromosomes. To address this issue, eukaryotic cells have regions at the ends of their chromosomes called telomeres, which contain repetitive sequences of noncoding DNA that act as protective caps. However, each time a cell divides, the telomeres become a bit shorter, as they absorb the brunt of the replication shortcomings. Eventually, the telomeres become too short to protect the genes, which could lead to loss of vital DNA and cell senescence or death.
In summary, without the ability to replicate the ends of DNA, chromosomes progressively shorten with each cell division, resulting in aging or the triggering of cell death mechanisms once critical DNA is affected.