The rate at which materials enter or leave depends on the surface area of the cell.
The rate at which materials are used or produced depends on the volume.
Smaller cells have short diffusion distance ( more efficient - molecules dont have to travel so far to get in and out of the cell, so it takes less time) while bigger cells have longer diffusion distance (less efficient).
As the cell grows, volume increases faster than the surface area (leading to decreased SA : VA ratio.
The larger the SA : V ratio, means that the cell can act more efficiently; for every unit of volume that requires nutrients or produces waste, there is more membrane to serve it
If the rate at which materials enter or leave is greater than the rate at which materials are used or produced (low SA : V ratio), the cell will eventually die. Cells tend to divide and remain small in order to maintain a high SA : V ratio suitable for survival.
Cells and tissues that are specialised for gas or material exchanges will increase their surface area to optimise material transfer