What is occurring during the mitosis phase?

Answer 1

Mitosis can be divided into four main stages. These are prophase, metaphase, anaphase and telophase.

During prophase, the chromosomes condense and become shorter and thicker, making them easily seen under a light microscope. The centrioles divide and move to opposite poles of the cell. The spindle develops from the centrioles. Towards the end of prophase, the nuclear membrane and nucleoli disappear.

During metaphase, the chromosomes line up at the equator of the cell and become attached to the spindle fibres at their centromeres. One sister chromatid is attached to a spindle fibre from one pole, whereas the other sister chromatid is attached to a spindle fibre from the opposite pole.

Anaphase is a very rapid stage. The centromere splits, the spindle fibres contract and separate the sister chromatids by pulling them to opposite poles of the cell, centromere first. As they are now separated, they are referred to as chromosomes in their own right.

Telophase begins when two distinct new groups of chromosomes have formed at opposite poles of the cell. The chromosomes uncoil and lengthen and become less visible under a microscope. The nuclear membrane and nucleoli reform. Cytokinesis occurs where the cytoplasm itself divides. In animal cells, this occurs by the constriction of the centre of the parent cell from the outside inwards. In plant cells, a new cell plate forms across the equator of the parent cell from the centre outwards and a new cell wall is laid down. These processes produce two new distinct daughter cells.

Answer 2

during which the cell is replicating itself.