Question

Most cells are quite small. What chemical or physical property keeps them from being huge?

Answer 1

Cells are dependent on external environment for survival because it attains nutrition, gases and excrete waste in external environment. They obtain these substance by means of cell membrane (using various modes of transport), then these substance are transported within the cell. As cell size increases, the rate at which cell volume increases is much larger than the increase in surface area, so the relative amount of surface area available to pass materials to a unit volume of the cell steadily decreases. This limits the size of cell.

Surface area of sphere = 4πr^{2. - proportional to square of radius}

Volume of sphere = (4πr³)/3 - proportional to cube of radius

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