Mitosis

Mitosis is a process of cell division that occurs in all eukaryotic organisms. It involves the duplication of a cell's genetic material and the subsequent division of that material into two identical daughter cells. Mitosis is essential for the growth, development, and repair of organisms, and it occurs in several distinct stages. I will provide a detailed step-by-step guide to mitosis, along with image to help you understand the process.

Step 1: Interphase

Before mitosis can begin, the cell must first go through a period of growth and preparation known as interphase. During interphase, the cell duplicates its genetic material and prepares for cell division. The DNA is in the form of chromatin, a diffuse network of DNA and proteins that can be seen in the nucleus of the cell.

Step 2: Prophase

Once interphase is complete, the cell enters prophase. During this stage, the chromatin condenses and becomes visible as individual chromosomes. Each chromosome consists of two identical sister chromatids, held together by a centromere. The spindle apparatus, which is responsible for separating the chromosomes, begins to form. The spindle fibers extend from two centrosomes located at opposite ends of the cell.

Step 3: Metaphase

During metaphase, the chromosomes align along the equator of the cell, known as the metaphase plate. The spindle fibers attach to the centromeres of the chromosomes, allowing them to be pulled apart later in the process.

Step 4: Anaphase

In anaphase, the spindle fibers begin to contract, pulling the sister chromatids apart at the centromeres. The separated chromatids are pulled towards opposite ends of the cell.

Step 5: Telophase

During telophase, the chromosomes arrive at the opposite ends of the cell, and a new nuclear envelope forms around each set of chromosomes, forming two nuclei. The spindle fibers disassemble, and the cell prepares for division.

Step 6: Cytokinesis

The final stage of mitosis is cytokinesis, during which the cell's cytoplasm divides in half, forming two daughter cells. In animal cells, a contractile ring of actin and myosin filaments forms around the cell, pinching it in two. In plant cells, a new cell wall forms between the two nuclei, dividing the cell in two.

And that completes the process of mitosis. The two daughter cells that are formed are identical to each other and to the parent cell. This process is essential for the growth, development, and repair of organisms, and it occurs continuously throughout our lives.