Question

Can there be mitosis without DNA replication in the ‘S’ phase?

Answer 1

Hint: Mitosis is a type of cell division in which the replicated chromosomes are separated into two new nuclei. This type of cell division gives rise to genetically similar cells in which the number of chromosomes is maintained.

Complete answer:
Mitotic division takes place with the DNA replication in the S phase which gives two new nuclei of genetically similar cells. There are two events that are associated with the S phase, one is the synthesis or replication of duplicate DNA and other one is duplication of the centriole. DNA duplication is very necessary as it helps to keep the number of chromosomes in the daughter cells the same. Hence, it can be said that mitosis is an equational division. Due to this duplication of the DNA the number of chromosomes is maintained and without which no mitosis can take place.

The S phase is followed by the cytokinesis which helps in dividing the cytoplasm, cell membranes and organelles into new cells which contain equal numbers of these cellular components. Mitosis and cytokinesis together define the mitotic phase of an animal cell which gives birth to two daughter cells which are genetically identical to the mother cell. There are various stages involved in mitosis division which are prophase, prometaphase, metaphase, anaphase, and telophase.

Note: During the mitosis cell division, the chromosomes which have already duplicated, condense and attach to spindle fibers that take away one copy of each chromosome to opposite sides of the cell.