Final answer:
Telomerase is necessary for the immortal cell division seen in cancer cells because it extends the otherwise shortened telomeres after each cell division, allowing for indefinite growth and division.
Step-by-step explanation:
Cancer cells are characterized by their ability to divide repeatedly and uncontrollably. One key factor enabling this constant division is the presence of the enzyme telomerase. In normal somatic cells, each time a cell divides, the telomeres at the end of chromosomes get shorter. This shortening process eventually leads to cellular ageing and death. However, in cancer cells, telomerase becomes active, especially once the telomeres have already shortened significantly. The activation of telomerase extends these shortened telomeres, essentially giving the cell the potential for unlimited growth and division, which is a hallmark of cancer. Scientists have found that if the action of telomerase in these cells can be inhibited, it could bring a halt to the cancerous cells' proliferation. This has significant implications for cancer therapy, providing a potential target for drug development. The inhibition of telomerase could lead to the inability of cancer cells to maintain their telomeres, which in turn would prevent them from dividing indefinitely.