In the process of binary fission, an organism duplicates its genetic material, or deoxyribonucleic acid (DNA), and then divides into two parts (cytokinesis), with each new organism receiving one copy of DNA.
In eukaryotic organisms, development involves cellular events such as mitosis, meiosis, and syngamy (fertilization), which variously proceed by nuclear division (karyokinesis), cytoplasmic division (cytokinesis), cytoplasmic fusion without the union of nuclei (plasmogamy), or nuclear fusion (karyogamy).
The classes are distinguished by the structure of flagellate cells (e.g., scales, angle of flagellar insertion, microtubular roots, and striated roots), the nuclear division process (mitosis), the cytoplasmic division process (cytokinesis), and the cell covering.
For a full treatment, see growth: In cells; cell: Mitosis and cytokinesis.
Prokaryotes reproduce principally by binary fission, in which the mother cell enlarges until it divides into two identical daughter cells, with cytokinesis representing the physical division into the two daughter cells.
Mitotic replications of the nuclear material presumably accompany or precede all divisions of the cytoplasm (cytokinesis) in protists.
The division of the cytoplasm (cytokinesis) is preceded by the division of the nucleus or nuclei.
After mitosis comes cytokinesis, the division of the cytoplasm.
In animal cells cytokinesis is achieved through the constriction of the cell by a ring of contractile microfilaments consisting of actin and myosin, the proteins involved in muscle contraction and other forms of cell movement.
In animal cells this is a pinching off (cytokinesis) of the cell membrane; in plant cells a new cellulose wall forms between the new cells.
Cytokinesis represents the major reproductive procedure of unicellular organisms, but it also occurs in the process of embryonic development and tissue growth and repair of higher plants and animals.
