Mitosis and the Physiology of Cell Division

Publisher Summary The reproduction of biological systems may be referred to the reproduction of cells. Subcellular entities such as viruses cannot maintain themselves indefinitely without parallel reproduction of the cells in which they live. The asexual reproduction of organisms such as flatworms is limited by the production of new cells, and all cases of sexual reproduction imply the generation of new cells after the mixing of genetic material from the parent cells. An evolutionary consequence of cellularity is implicit in the designation of multicellular organisms as higher organisms. Single cells can develop a high level of variety and complexity of structure and function. In the development of a multicellular organism, cell division, beginning with the egg, is the essential step toward differentiation. If mitosis is a device for the distribution of sister genes to sister cells, the chromosomes may be viewed as a system in which the numerous genes are packaged into a small number of units. Mitosis is accompanied by some changes in the physical state or texture of the cytoplasm, which have been assessed as viscosity changes.