Size is an important phenotypic characteristic of any cell with consequences for tissue and organ architecture. In proliferating cells, size is the result of cell growth and cell division, which roughly halves the cell size each generation. Cells proliferating in unchanged conditions maintain a particular size distribution, suggesting that these two processes are coordinated . For most measurements size refers to geometric size or cell volume. Light microscopy and impedanceUbased tools (Coulter principle) for volume measurements have long been employed. An alternative approach is to consider growth as the creation of new biomass, mainly proteins, carbohydrates and lipids.