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All living organisms start their life journey from a single cell. A single cell grows to form multiple cells, thereby including all microorganisms. Initially, the cells reproduce into two cells. The process continues when parent cells give rise to daughter cells every time they divide. The two new daughter cells can grow by themselves, divide further, and develop more cells, increasing the cell population.
Cell Division
During cell division, DNA replication and cell growth happen in cells. The entire process of cell division, involving DNA replication, cell growth, correct division, results in progeny cells that contain intact genomes. The sequential event where the cell divides into daughter cells to constitute millions of cells is called the cell cycle. Hence Cell Cycle and Cell Division are essential processes in all living organisms.
Phases Of Cell Cycle & Cell Division
The duration of the cell cycle varies based on organisms and cell types. There are two primary phases of the cell cycle.
- Interphase
- Mitosis phase
Interphase
The phase between two successive Mitosis phases is called Interphase. It takes only one hour in the 24-hour average duration of a human cell cycle. Interphase accounts for almost 95 percent of the cell cycle’s duration. The cell prepares itself for dell division, cell expansion, and DNA replication in a sequential manner during interphase, which is also known as the resting phase.
There are three sub-phases of the Interphase. They are the G1 phase (Gap 1), S phase (Synthesis), G2 phase (Gap 2). During these phases, the cell grows, DNA replicates in the nucleus, centriole duplicates in the cytoplasm, and proteins get synthesized and remain metabolically active.
Mitosis phase
Mitosis or actual cell division occurs in this phase. Nuclear division happens in this phase, where daughter chromosomes are separated. In mitotic cell division, the nuclei of duplicated chromosomes are split into two new nuclei. This is called karyokinesis and eventually results in cytoplasm division called cytokinesis. The components of the cells get reorganized in this phase. This phase involves four stages of nuclear division – Prophase, Metaphase, Anaphase, Telophase.
- Prophase: This first stage of karyokinesis of mitosis occurs after the S and G2 phases of interphase. New DNA molecules formed are condensed with chromosomal material in this phase. Compact mitotic chromosomes are formed. Chromosomes are composed of two chromatids at the centromere, which undergoes duplication.
- Metaphase: In this phase, the centromere holds two sister chromatids. Kinetochores, small disc-shaped structures, are formed at the surface of the centromeres. They are attached to the chromosomes through the spindle fibers. Later, the chromosomes get aligned through spindle fibers to both poles of the spindle equator.
- Anaphase: Chromosome split simultaneously to two daughter chromatids or daughter nuclei. In this phase, the centromeres split and the chromatids separate. Chromatids start migrating towards the two opposite poles.
- Telophase: In this period, chromosomes start losing their uniqueness. Individual chromosomes are no longer visible, and they are clumped together at opposite spindle poles. They form discrete elements. Chromosome clusters are covered by a nuclear envelope, where two daughter nuclei are formed at each pole. Golgi complexes, endoplasmic reticulum, nucleolus develop at this stage.
Cytoplasm Division – Cytokinesis
- Cell Cycle and Cell Division are completed in human cells as the cell divides into two daughter cells by the division of cytoplasm called cytokinesis.
- A furrow emerges in the plasma membrane of animal cells, which deepens, separating the cell cytoplasm in two and later reuniting the center.
- Wall development in plant cells begins in the cell’s center. This later grows outwards, which meets the lateral walls. New cell walls form, and in between the new walls, two adjacent cells are formed. The cytoplasmic division occurs where mitochondria and plastids are distributed to the divided two daughter cells.
MEIOSIS
In Meiosis, cell cycle and cell division happen when a single cell divides twice. It produces four cells containing half the amount of genetic information that was originally contained. Hence, one meiosis cell divides twice, resulting in four daughter cells. These are the sex cells in humans – sperm in males and eggs in females.
Conclusion
You now can understand the difference between a cell cycle and cell division. A cell has a series of phases that it has to undergo in a cell cycle and cell division. The series of phases helps the cell split and increase in number. Cell cycle and cell division study material will enhance your knowledge and develop your learning towards cell division related to the cell cycle and the time taken by cells to replicate. Mitotic cell division is a type of nuclear division in which a parent cell splits into two identical daughter cells.
