Telomerase, an eukaryotic ribonucleoprotein (RNP) complex, consists of an essential RNA template and a reverse transcriptase termed as human telomerase reverse transcriptase (hTERT). By using this reverse transcriptase enzyme, telomerase RNP maintains its telomeric length in all cancer cells and in few stem cells. As cells age, telomerase level decreases and telomere get shorten, leading to senescence. Presence of telomerase helps delay the senescence due to active production of telomere, leading to cell turning malignant and eventually cancerous. In this experiment, we would investigate the telomerase activity tested using q PCR and telomerase level using western blot in three different cell lines, HEK-293, HeLa and A549. Hypothesis: - Where HEK-293 cells have longer telomeres and higher telomerase activity, HeLa and A549 cell lines will have varied length of telomere but higher telomerase activity.