Continuous cell lines are characterized by which property?

• A. Die after a few divisions
• B. Transform and divide indefinitely
• C. Do not adhere to surfaces
• D. Require constant growth factors

Answer: (B)

Continuous cell lines proliferate indefinitely in culture because they have acquired changes that bypass normal cellular aging and crisis limits. This immortality often comes from mechanisms like maintaining telomeres, often via telomerase activation, and disabling key tumor-suppressor pathways (such as p53 and Rb), allowing cells to keep dividing beyond the finite lifespan of normal somatic cells. Because of this unlimited division potential, they can be propagated for many passages, which is the defining feature distinguishing them from finite primary cells that die after only a few divisions. Some continuous lines may require certain growth factors or adhere to surfaces, but those aspects describe culture conditions rather than the essential property; the hallmark is their ability to divide indefinitely.