4 Phases of a Cell Cycle

WHAT IS CELL CYCLE?

In layman’s terms, the cell cycle is a series of events that occur intravenously in a cell, culminating in the generation of two daughter cells via DNA duplication and cytokinesis, as well as the division of cell organelles. 

The Cell Cycle’s Phases

The cell division cycle, often known as the cell cycle, is a four-stage process in which a somatic cell undergoes two major molecular processes: parent chromosomal duplication (which occurs in S phase) and equal chromosome detachment from daughter cells (occurring during M phase)

The cell cycle in eukaryotic cells is divided into two distinct phases: interphase and mitotic phase. While the cell grows and duplicates a DNA copy during interphase, the cell separates its DNA into two sets during the mitotic phase, resulting in the division of the cytoplasm into two daughter cells.

The following are the four major phases:

Phase 1 (Gap 1)

• This is the first stage of the interphase, also known as the G1 or first gap phase, in which little alterations are noticed due to the cell’s metabolic hyperactivity
• Changes in chromosomes from condensed to expanded states, as well as a variety of metabolic activities leading to the start of DNA replication, characterise this period
• In this phase, the chromatin fibers are less coiled and slender, fully stretched, and ready for transcription. Transcription results in the synthesis of RNAs as well as a sequence of protein molecules that are required for DNA replication to begin
• The G1 phase lasts longer than the other three and differs from cell to cell
• As the cell matures and assembles the building blocks of chromosomal DNA and related proteins, this is an important phase. Furthermore, it saves enough energy to complete chromosome replication
• In this phase, DNA synthesis begins at a certain checkpoint. Once all of the biochemical activities at this point have occurred, the cell moves on to division

Phase of Synthesis (S)

• The interphase is in the midst of vigorous DNA and histone synthesis
• Here, related proteins and DNA replication help the chromosomes replicate. The majority of histone protein synthesis takes place during this phase, however some occurs during the G1 phase
• Because DNA replication is discontinuous and semi-conservative, an identical pair of DNA molecules is created
• The sister chromatids are suitably connected to the centromeric region even after the chromosomes have doubled. The cell’s chromosomal count remains constant
• Animal cells have centrosomes in the center that are connected by centrioles that are perpendicular to each other. The centrioles play an important role in the cell division process
• The centrosome is replicated during this phase, resulting in the mitotic spindle, the machinery that coordinates chromosomal movement during mitosis

Phase G2 (Gap 2)

• The S phase comes after this phase. Because the chromosomes are divided into two chromatids, the cell possesses twice the amount of DNA
• The cell regenerates its energy by generating proteins required for chromosomal manipulation
• Only a small percentage of cell organelles are reproduced. The cytoskeleton dismantles to make room for mitosis
• It’s possible that the cell will continue to expand. The final mitotic preparations must be completed before the cell starts the first phase of mitosis

Phase M (Mitotic)

• The G2 phase takes its place after this one. The cell divides into two daughter cells with an equal number of chromosomes distributed between them. When the M phase transitions to the G1 phase, the next cell cycle begins to repeat itself. However, some cells do not enter the G1 phase. G0 cells are what they’re called
• It is divided into the following sub-phases
• The nucleus dissolves, spindle fibers develop, and DNA condenses into sister chromatids during prophase
• By attaching their centromeres to the spindle fibers, the sister chromatids orient alongside the cell equator during metaphase
• Anaphase is the separation of sister chromatids at the centromere, with the mitotic spindle pulling them to opposing poles of the cell
• Telophase – The chromosomes arrive at opposite poles to unwind into tiny DNA strands. The fibers in the spindle disappear. The nuclear membrane reappears
• Cytokinesis is a process in which the cell membrane separates and animal cells drift out. Plant cells develop a cell plate that eventually becomes a new cell wall
• When cells finish the cell cycle and are not actively preparing to divide, they enter the G0 phase, which is the inactive phase. Only a few of these cells seem to survive in this stage permanently

CONCLUSION

Our body’s cells are extremely sophisticated. They know when to replicate themselves, when to relax, and when to stop splitting entirely. Duplication happens for a variety of reasons, the most common of which is to replace aged cells. This duplication takes place at several phases, with checkpoints along the route to ensure that the cell is replicating correctly.If the cell successfully completes each phase and checkpoint, the parent cell replicates, and the young cells begin their first cell cycle.