CELL DIVISION
CHAPTER 3
Biological Essence and Importance of the Cell Division
Section 3.1. Cell division is a unique biological mechanism, through which the
reproduction of living organisms is realized. Its biological essence and
importance find expression in redistribution of the genetic material in the
daughter cells and preservation of the hereditary information in the
following generations.
In unicellular organisms the cell division is a process of reproduction, since
from one mother cell two or more daughter cells are formed and each of them
participates independently in the following life cycle. In multicellular organisms,
through multiple divisions of the cells in particular tissues and organs the growth
and development of individuals is realized, that form specialized regenerative
cells — spores, gametes, eggs, spermatozoa, etc. The following generations are
reproduced from single regenerative cells or through their fusion and zygote
formation.
In the course of evolution different modes and types of cell division are
created, in which the basic predestination as a mechanism of reproduction
of the living organisms has been preserved. This question will be
considered once more further.
Discovery and Insight into the Essence of Cell Division
Section 3.2. The discovery of cell division and penetrating its essence is not a single act,
but a long process of researchs. A detailed study of the history on this
problem is given in the monographs by Katznelson (1939, 1963) and “History
of Biology” (1972, 1975). According to these literary sources, first of all cell
division in filamentous algae is observed in 1832 by the Belgian naturalist
Charles Dumortier. In 1835 Hugo von Mohl has described dividing cells in
algae of Conferva genus (Fig. 3–1), but he has not noticed cell nucleus and
has not known anything about it. Only several years after K. Nägeli (1842 b)
also has described division of cells during pollen grain formation (Fig. 3–2),
some of them with nuclear structures. In the second part of his publications
under the common title “Cell Nucleus, Cell Division and Growth of the Cells in
Plants” Nägeli (1844—46) arrives at the extremely important idea, that “the
mother cell gives rise to two or more daughter cells through the process of
division, observed for the first time by von Mohl”. At that time Remak (1858)
has also observed division of cells in tissues of animal organisms and
erythrocytes of chicken embryos (Fig. 3–3).