1.3 Limitations to Cell Size (SA:V ratio)

SA:V

SA- Total area of outer layer

V- Space occupied

Volume increases faster than surface area

How it works

The smaller the cell, the higher the SA:V ratio

Benefits

Higher SA:V ratio allows faster material exchange across the plasma membrane. Required substances come in, waste is removed

Limitations

Decrease in SA:V ratio (increase in cell size) can slow material exchange, giving cells a size limit, as they must divide or die if the transfer cannot occur faster enough to sustain the cell.

Compensation

Some cells compensate for the increased size by highly folding the SA