MYSTERY OF THE CELL : How Does Cell Know Their Actual Size?

                How does knows their actual size ? 

Researchers have finally begun to identify potential size-sensing mechanisms within cells, but they admit there's still a lot to learn.

From short and heavy to tall and thin, people come in various sizes—and so do their cells. An egg cell dwarfs a sperm, for example, and both are dainty compared with some of our neurons that stretch to more than a meter in length. But within specific cell types, cells actually stick to “a fairly narrow range of sizes,” says cell biologist Marc Kirschner of Harvard Medical School in Boston.

Biologists have puzzled over how cells know when they've reached the right size. “The question has been there for a long time. The answers haven't,” Kirschner says. Researchers have finally begun to identify potential size-sensing mechanisms within cells, but they admit there's still a lot to learn.

When a cell does deviate from the norm, it may signal a malfunction: Skewed cell size is a hallmark of some diseases. Take small-cell carcinoma, a type of cancer that usually sprouts in the lungs, in which tumor cells are so puny that they barely have room for any cytoplasm.