Do you know what a cell is? A cell is the basic structural and functional—and also the smallest—unit of all living organisms. Then, why do you think most cells are so small? It’s because the size of the cells influences their functions. If the cell size increases, the cytoskeleton, communication, cell diffusion, and transportation of nutrients become less efficient. Cells are divided and reproduced by a process called the cell cycle. It includes interphase, mitosis, and cytokinesis.
The first stage of the cell cycle, interphase, is composed of three stages: G1, S, and G2. During the G1 stage, a cell increases in size and carries out some normal functions such as making proteins and getting ready to duplicate DNA. During the S stage, the cell starts to copy DNA to prepare for cell division. Last but not least, the stage in interphase that follows the S stage is the G2 stage. Also, the proteins that make microtubules are created here. It’s the final stage to get ready to start cell division.
The second stage is called mitosis. Before we begin, we should know the differences between chromosomes and chromatin. Chromosomes are the structures that contain genetic material and are compressed versions of DNA. Chromatin is found in the nucleus and is the relaxed structure of DNA.
To begin with mitosis—it’s similar to interphase—it includes four stages: prophase, metaphase, anaphase, and telophase. First of all, prophase is the first and the longest phase in mitosis. The nucleolus disappears, the nuclear membrane is broken down, and chromatin condenses into chromosomes. As prophase ends, a spindle apparatus is created and it attaches to the sister chromatids, which have exact copies of DNA. Mitosis is the shortest phase; sister chromatids are pulled and lined up at the center of the cell to form a metaphase plate. During
anaphase, sister chromatids are pulled apart and separated due to the shortening of the microtubules in the spindle apparatus. The segregated sister chromatids are now called chromosomes, and they move to the poles of the cell. During the last stage of mitosis,
telophase, the chromosomes and spindle apparatus are decondensed, and two nuclear membranes and nucleoli are formed.
Lastly, cells go through cytokinesis. There are big differences between animal and plant cells. In animal cells, cleavage furrows and microfilaments are formed. The microfilaments follow the cleavage furrow to cut the cytoplasm, and eventually two cells are created. On the other hand, in plant cells, since there is a cell wall, instead of cutting, the cell creates a cell plate between the two daughter nuclei.
In conclusion, the cell cycle is important for cells to grow, divide, develop, and eventually die. It includes interphase (G1, S, G2), mitosis (prophase, metaphase, anaphase, telophase), and cytokinesis. Unhealthy cells might affect our bodies negatively, such as causing cancer. It’s essential to stay healthy to keep our cells healthy and prevent sickness.
By. James Yoon