Why cells stay small: surface area against volume
Lengths in arbitrary units · cube: SA = 6L², V = L³, SA:V = 6/L · dye soaks a fixed 0.5 units in from every face in the same time
Size and shape of the cell
Surface area
Volume
SA:V ratio
Volume reached by dye
Cut face after soaking in dye
SA:V against side length
Change the side length or the shape to begin.
- Doubling the side halves SA:V
- A large cell has a low SA:V
- Flattening raises SA:V at the same volume