Cell Cycle Significance

Introduction

The cell cycle is the essential process of the human body, it produces cells in the body simultaneously throughout our life, and the cell cycle can be termed as cell division also. The Cell cycle’s whole process is to divide and produce new cells to sustain life. Cell cycle holds an important chunk in the syllabus of XI-XII standard students and it is also included in the syllabus of NEET biology.

Cell cycles have different phases and interphases during the cell cycle. We’ll discuss that all in the article. The cell cycle has many related topics and there are many terms and processes of cell cycles used in other lessons also, which makes the cell cycle more necessary to understand. So here unacademy has curated the best study material for you in this article to help XI-XII students. Learn it with focus and have the edge for your exams.

About Cell Cycle

Cells are the essentials of our body, they perform a cycle called the cell cycle in which they kind of reproduce another cell in our body by cell division. The cell cycle has occurred in the cell itself, Cells get halved into two daughter cells and these daughter cells are DNA replication of the mom cell. To get divided, cells divide their cytoplasm and other organelles into two parts and hence come into existence.

During the cell cycle or cell division, there are various phases and interphases of this process. Generally, after the division of cells that have nuclei present, they land into two phases in which they land, phases are interphase and mitotic, which further have some more processes to complete the cycle, and cells without nuclei fall into B periods, C periods, etc., which are part of DNA replication process.

History

Professor of Institute of anatomy Walther Fleming proposed cell cycle theory during the 19th century. He mapped that the nucleus always got halved before the cell, he researched towards the cell cycle and found the process of mitosis and meiosis, other scientists also contributed in the presentation of the cell cycle.

Phases of Cell Cycle

There are different cell cycle phases, they differ by organelles present in cells, as discussed cells with nuclei land into two phases: 1.) Interphase and 2.) M phase. Which further has some process to complete the cell cycle. It takes about 24 hours generally for a cell to perform cell division or cell cycle.

At rest

When a cell completes its cycle, it gets into the resting stage for some time before starting another cell division. This is the starting phase of the cell cycle

Interphases

Interphase is the phase after the M phase that a cell has performed during its previous cell division. Interphase has three phases of cell division in itself, G1, S, G2 are the three phases, In interphase, the changes start taking place in the cell, its size and organelles increase in size and prepare for DNA replication in other stage and finally proceed to mitosis or cytokinesis after the last stage.

Gap1 (G1) phase

G1 or gap 1 is the start of interphases, cells start growing and organelles also grow with cells. As G1 is the phase after the successful M phase of the previous cycle, the metabolic activities of the cell get slowed down during the M phase of cell division, which in the G1 phase again reach to high rate, G1 phase is also called the growth phase of the process. After the G1 phase, Cell has three options to proceed next, the cell enters the synthesis phase and continues cell division, to stop division and enter the G0 stage again to perform differentiation, or to start the cell division cycle again. Restrict point is the point which performs transitions and it is the point that decides the next proceeding of the cell.

Synthesis (S) phase

The synthesis phase starts Replicating DNA in itself and initiating itself to enter the G2 phase. In the S phase the cell partitions chromosomes and other organelles to get divided. When the DNA in the cell gets doubled and organelles like centrioles are also halved, then the cell is ready to enter the Gap 2 (G2) phase.

G2 phase

Cells continue to grow in the G2 phase, cells start forming spindles in them. all macromolecules, proteins, organelles get replicated and multiplied in this phase before entering the mitotic phase and cytokinesis phase.

M (mitotic) phase

This phase is the chromosome division process, in this phase, a cell multiplies and aligns its chromosome to get separated into two cells. Cell partitions its nuclei in two halves. This process is divided into four stages. 1.) Prophase 2.) Meta phase 3.) Anaphase 4.) Telophase.

Prophase: The nucleolus starts vanishing and the spindle fibers start developing. Chromosomes start condensation.

Metaphase: Centromeres reach the layers of cells from inside. Spindle gets fully evolved and the force to separate the cell from the spindle starts. Both nuclei move towards opposite poles inside a cell.

Anaphase: The sister chromatids get separated and attach to opposite poles with chromosomes.

Telophase: spindle gets separated in this phase.

Cytokinesis

Cytokinesis instantly occurs after the M phase. Cytokinesis divides all cellular components or organelles of a cell into almost two halves and starts giving birth to two daughter cells and lastly, cell division takes place and the cell gets divided into two daughter cells.

Types of cell division

As cells divide to complete the cell cycle. There are two ways the cell can get divided and start another cell cycle 1.) Mitosis and 2.) Meiosis.

Mitosis: the exact copies of cells that came into existence at the end of cell division occurred during the cell cycle. Mitosis is found in almost every organ of the body where there is the occurrence of the cell cycle.

Meiosis: Rather than replicas of the same cells. The division products we get during the meiosis process are sperm or either egg cells.

Some organisms which have single cells present in them, perform binary fission to reproduce and cause cell division.

Conclusion

Above from here, we came through the cell cycle. We learned its importance, process, phases and its various general facts also. Cells are the essentials of our body, they perform a cycle called the cell cycle in which they kind of reproduce another cell in our body by cell division. The cell cycle has occurred in the cell itself, Cells get halved into two daughter cells and these daughter cells are DNA replication of the mom cell. To get divided, cells divide their cytoplasm and other organelles into two parts and hence come into existence.