It is a two-step process that reduces the chromosome number by half—from 46 to 23—to form sperm and egg cells. When the sperm and egg cells unite at conception, each contributes 23 chromosomes so the resulting embryo will have the usual Meiosis also allows genetic variation through a process of gene shuffling while the cells are dividing.
Other chapters in Help Me Understand Genetics. Genetics Home Reference has merged with MedlinePlus. Learn more. The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health. This page has been archived and is no longer updated. Mitosis is a process of nuclear division in eukaryotic cells that occurs when a parent cell divides to produce two identical daughter cells.
During cell division, mitosis refers specifically to the separation of the duplicated genetic material carried in the nucleus. Mitosis is conventionally divided into five stages known as prophase, prometaphase, metaphase, anaphase, and telophase. While mitosis is taking place, there is no cell growth and all of the cellular energy is focused on cell division. During prophase, the replicated pairs of chromosomes condense and compact themselves. The pairs of chromosomes that have been replicated are called sister chromatids, and they remain joined at a central point called the centromere.
A large structure called the mitotic spindle also forms from long proteins called microtubules on each side, or pole, of the cell. It only occurs in somatic cells and helps the growth of organisms. Mitosis occurs via four phases: prophase, metaphase , anaphase, and telophase.
Prior to mitosis, DNA replication should happen in order to double the number of chromosomes. During prophase, the nuclear membrane and nucleolus disappear while chromosomes condense and become visible. In metaphase, chromosomes arrange themselves at the cell equator as the spindle formation is completed. The chromosomes split from the centromeres and separate into sister chromatids.
Then the sister chromatids start to separate during the anaphase. Finally, when chromosomes reach the poles of the cell, nuclear membranes start to reform and surround each set of chromosomes. Cell division is the process of self-replication of cells that results in new cells from parent cells. Whereas, mitosis is the division of the cell nucleus resulting in two genetically identical daughter nuclei. So, this is the key difference between cell division and mitosis. Furthermore, cell division includes nuclear division and cytokinesis while mitosis consists of four phases: prophase, metaphase, anaphase, and telophase.
Moreover, a further difference between cell division and mitosis is that both somatic and germ cells undergo cell division while only somatic cells undergo mitosis. Also, cell division takes more time to complete than mitosis. Hence, we can consider this too as a difference between cell division and mitosis.
0コメント