What limits the size to which a cell can grow?

Answer 1

Three main limits to cell size:
1. Diffusion is too slow to move materials into the interior and out of the interior of a large cell.
2. DNA can't be copied quickly enough to handle all the protein synthesis needs of a large cell.
3. The larger the cell gets, the smaller the surface area to volume ratio becomes. This means that the cell has too much material inside to be served by the amount of plasma membrane that surrounds it. The plasma membrane has to handle all the materials coming in and going out. If the cell is too big, it's like having too many people in a gymnasium with too few doors. It's not going to work.

Answer 2

surface area:volume ratio. The bigger cells grow, the smaller this ratio gets. Think of a sphere, try calculating the surface area and volume of 2 different size spheres, the bigger one will have a smaller SA:V ratio. With less SA for the V, cells cannot have enough space to interact with the environment and get enough energy to support its size.