Cell Culture Synchronization - Cells in suspension cultures vary greatly in size, shape, DNA, and nuclear content. Moreover, the cell cycle time varies considerably within individual cells. Therefore cell cultures are mostly asynchronous.

It is essential to manipulate the growth conditions of an asynchronous culture in order to achieve a higher degree of synchronization.

A synchronous culture is one in which the majority of cells proceed through each cell cycle phase (G₁, S, G₂ and M) simultaneously. Synchronization is expressed as percentage synchrony of cells in suspension cultures. Synchronization can be achieved by physical or chemical methods.