Final answer:
Cells protect DNA from being shortened during replication by using telomeres and the enzyme telomerase, which extends the repetitive nucleotide sequences at the ends of chromosomes, thus preserving genetic information and allowing cells to divide more times.
Step-by-step explanation:
Why Do Cells Attempt to Extend Their Lifespan During Replication?
Cells have multiple mechanisms to ensure they can replicate their DNA accurately and maintain their function over time. One of these crucial functions is to protect DNA from being shortened during replication due to the end replication problem, which could lead to the loss of important genetic information. This shortening occurs because DNA polymerases, the enzymes responsible for DNA replication, cannot replicate the very end of linear chromosomes, which are structures that protect DNA. However, structures called telomeres and the enzyme telomerase help to extend the life of cells by adding repetitive nucleotide sequences to the ends of chromosomes, thus preventing vital genetic information from being lost during cell division.
Over time, with each cell division, telomeres may become shorter, leading to a limit on the number of times a cell can divide, known as the Hayflick limit. When telomeres become too short, this can trigger cell senescence or apoptosis, which are processes that prevent the further division of cells with potentially unstable genomes. However, in some cells, such as stem cells and cancer cells, telomerase activity is higher, which allows these cells to divide many more times, or even indefinitely, which can contribute to tissue regeneration or cancer progression, respectively.
Therefore, the correct answer is 2) Because they protect DNA from being shortened during replication. This protective role ensures the integrity of genetic information during the cell division process, thereby extending the lifespan of cells and maintaining the health of the organism.