Normally which cells if any are immortal?

Answer 1

Cells exhibit an effect known as the Hayflick limit, which states that all cells can divide and reproduce only a limited amount of times. There are a few exceptions to that rule, as some cells known as immortal cells display no signs of aging and can be terminated only by outside factors, such as starvation or if their host dies.

Human germ cells (ovum and sperm) have no Hayflick limit. Many species of bacteria are considered immortal as they continue dividing until an outside force terminates them. Similarly, diseases of the cell cycle (such as cancer) are able to produce immortal cells as they grow and reproduce without limitations.

Answer 2

Stem cells are generally considered to be immortal as they have the ability to continuously divide and differentiate into other cell types. Germ cells, which are involved in reproduction and pass on genetic material to the next generation, also exhibit immortality through meiosis and gametogenesis processes.