Radius(mm) 0.5 1.0 1.5 3.0 3.5 Surface area(SA) 3.4 12.6 28.6 113.4 153.6 Volume(V) 0.6 4.7 14.4 112.5 179.5 Ratio of SA to V 6:1 3:1 2:1 1:1 0.8:1 As the radius of the cell increases what difference do you observe in surface area and volume of the cell.

As the cell increases in size so does it's volume and surface area. But the surface area to volume ratio decreases as the cell grows. The volume of the cell is cubed as compared to cell size and surface area is squared. More the radius of the cell smaller is the surface area to volume ratio leading to less exchange between the cell and its surroundings. As the radius of the cell increases its demand for resources also increases. If the cell grows beyond a particular size not enough materials are able to cross the cell membrane to meet the energy requirements of the large cell because of the smaller surface area to volume ratio. So to accommodate the increasing demand for nutrients the cell must either stop growing or divide into smaller cells.

Radius(mm) 0.5 1.0 1.5 3.0 3.5 Surface area 3.4 12.6 28.6 113.4 153.6 Volume (V) 0.6 4.7 14.4 112.5 179.5 Ratio of SA to V 6:1 3:1 2:1 1:1 0.8:1 How does the radius affect the ratio of surface area and volume of the cell?

As the cell grows in size its radius increases and also its demand for more resources. As we have seen in the table, that as the radius increases surface area of the cell also increases. But the surface area to volume ratio decreases as the radius increase. Thus, if a cell grows beyond a limit then enough materials won't be able to pass through the plasma membrane fast enough to accommodate the increasing volume.