Cell cycle and cell division
The cell cycle, also known as the cell-division cycle, refers to the series of events
occurring within a cell that result in its division into two daughter cells.
This process encompasses the cell's growth, duplication of its DNA and
organelles, followed by the division of its cytoplasm, chromosomes, and other
components into two daughter cells, a procedure known as cell division.
In eukaryotic cells, which possess a cell nucleus and encompass animal, plant,
fungal, and protist organisms, the cell cycle consists of two primary phases:
interphase and the M phase, which comprises mitosis and cytokinesis.
During interphase, the cell increases in size, gathers necessary nutrients for
mitosis, and duplicates its DNA and certain organelles.
Its successive stages differ in specialized biochemical processes that prepare the
cell for division, yet are typically not morphologically distinguishable.
During the M phase, replicated chromosomes, organelles, and cytoplasm separate
into two new daughter cells.
To ensure the proper replication of cellular components and division, cell cycle
checkpoints are established after each major stage of the cycle to regulate whether
the cell proceeds to the next phase.
In prokaryotic cells lacking a nucleus, the cell cycle is divided into the B, C, and
D phases. The B phase spans from the conclusion of cell division to the initiation
of DNA replication. DNA replication takes place during the C phase.
The D period represents the interval following DNA replication and preceding the
division of the bacterial cell into two daughter cells.
In single-celled organisms, a single cell-division cycle serves as the method by
which the organism reproduces. In multicellular organisms like plants and animals,
a series of cell-division cycles is the process by which an organism develops from
a single-celled fertilized egg into a mature form.
