Explain the process of mitosis in animal cells.

Mitosis in animal cells is a process of cell division that results in two genetically identical daughter cells.

Mitosis is a fundamental process for life, allowing cells to reproduce in a controlled manner. It is a part of the cell cycle and is preceded by the S phase, where DNA is replicated, and followed by cytokinesis, which divides the cytoplasm and separates the two new cells. Mitosis itself is divided into four main stages: prophase, metaphase, anaphase, and telophase.

During prophase, the first stage of mitosis, the chromatin condenses into chromosomes, and the nuclear envelope breaks down. Each chromosome is composed of two sister chromatids, which are identical copies of the original chromosome. The centrosomes, which were duplicated during the S phase, move to opposite poles of the cell and begin to form the mitotic spindle, a structure that will help separate the sister chromatids.

Metaphase, the second stage, is characterised by the alignment of the chromosomes along the metaphase plate, an imaginary line equidistant from the two centrosomes. The spindle fibres attach to the centromeres of the chromosomes, preparing them for separation.

Anaphase follows metaphase. During this stage, the sister chromatids are pulled apart by the spindle fibres and move towards the opposite poles of the cell. This ensures that each new cell will receive one copy of each chromosome.

The final stage of mitosis is telophase. Here, the chromosomes reach the poles and begin to decondense back into chromatin. The nuclear envelope reforms around each set of chromosomes, creating two separate nuclei within the cell.

Following mitosis, the cell enters cytokinesis. This is not a part of mitosis, but it is a crucial step in cell division. During cytokinesis, the cytoplasm is divided, and two new cells are formed. Each new cell has an identical set of chromosomes and is genetically identical to the original cell.

In summary, mitosis is a complex and highly regulated process that ensures the accurate duplication and distribution of a cell's genetic material. It is essential for growth, repair, and reproduction in animal cells.