Mitosis is the type of cell division occurring in the somatic cells of the body. Here, the number of chromosomes and the DNA content remains same, that is, unlike that of meiosis it do not get halved.
Mitosis consists of four different phases or stages – prophase, metaphase, anaphase and telophase.
Coming to your question –
Prophase Is the first phase of mitosis. As observed under an electron microscope, following are the changes seen during the prophase of mitosis –
· The chromatin fibers have shortened and turned into chromosomes
· The centrioles have duplicated and have started moving towards the opposite poles
· The nucleolus has degenerated
· The nucleus has also disappeared
· Other cell organelles are not visible
These are the changes observed in a cell undergoing the prophase stage of mitosis. I hope this helps.