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.
This same mechanism is responsible for the regeneration and healing of hair, skin,
blood cells, and certain internal organs.
, State Phase Abbreviation Description
Resting Gap 0 G0 In this phase the cell has left the cycle and
does not divide further
Interphase Gap 1 G1 Cell growth. Here everything is prepared
for dna synthesis
Synthesis S Here DNA replication takes place
Gap 2 G2 It is the Growth and preparation for
mitosis. This phase ensures that
everything is ready to enter the M
(mitosis) phase and divide.
Cell Mitosis M Here Cell division occurs. This phase
division ensures that cell is ready to complete its
cell division .
G0 Phase
G0 is a resting phase where the cell has exited the cell cycle and ceased dividing.
The cell cycle begins with this phase. In multicellular eukaryotes, non-proliferative
cells typically transition from the G1 phase into the quiescent G0 state and can
remain in this state for extended periods, sometimes indefinitely, as frequently
observed in neurons.
This is typical for fully differentiated cells. Certain cells enter the G0 phase in a
semi-permanent state and are classified as post-mitotic, such as certain liver,
kidney, and stomach cells. Many cells do not enter G0 and continue to divide
throughout an organism's life, such as epithelial cells. The term "post-mitotic" is
sometimes used to describe both quiescent and senescent cells. Cellular senescence
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.
This same mechanism is responsible for the regeneration and healing of hair, skin,
blood cells, and certain internal organs.
, State Phase Abbreviation Description
Resting Gap 0 G0 In this phase the cell has left the cycle and
does not divide further
Interphase Gap 1 G1 Cell growth. Here everything is prepared
for dna synthesis
Synthesis S Here DNA replication takes place
Gap 2 G2 It is the Growth and preparation for
mitosis. This phase ensures that
everything is ready to enter the M
(mitosis) phase and divide.
Cell Mitosis M Here Cell division occurs. This phase
division ensures that cell is ready to complete its
cell division .
G0 Phase
G0 is a resting phase where the cell has exited the cell cycle and ceased dividing.
The cell cycle begins with this phase. In multicellular eukaryotes, non-proliferative
cells typically transition from the G1 phase into the quiescent G0 state and can
remain in this state for extended periods, sometimes indefinitely, as frequently
observed in neurons.
This is typical for fully differentiated cells. Certain cells enter the G0 phase in a
semi-permanent state and are classified as post-mitotic, such as certain liver,
kidney, and stomach cells. Many cells do not enter G0 and continue to divide
throughout an organism's life, such as epithelial cells. The term "post-mitotic" is
sometimes used to describe both quiescent and senescent cells. Cellular senescence
