Final answer:
The life of a human cell has been extended by injecting it with the enzyme telomerase, which lengthens telomeres and can potentially reverse age-related degeneration.
Step-by-step explanation:
Researchers have extended the life of a human cell by injecting it with telomerase. Telomerase is an enzyme that adds repetitive nucleotide sequences to the ends of eukaryotic chromosomes, known as telomeres, which help protect the chromosome from deterioration during cell division. This process is particularly important as it is associated with the aging of cells and has potential for applications in regenerative medicine. In experiments with telomerase-deficient mice, the reactivation of telomerase led to the extension of telomeres, reversed age-related degeneration, and improved organ functions, underscoring the potential benefits for age-related human diseases.