Meiosis is the type of cell division that produces gametes, the reproductive cells of a sexually reproducing organism. During meiosis, the genetic material replicates and is divided between daughter cells so that each gamete contains a single copy of each chromosome instead of two copies.Continue Reading
Meiosis only occurs in primordial germ cells in the reproductive organs and not in somatic cells, which make up the majority of the cells in the body. In males, meiosis is called spermatogenesis because it produces sperm cells. In females, the process is called oogenesis because it produces egg cells, also known as ova. In spermatogenesis, four fully functioning sperm are produced at the end of meiosis. In each round of oogenesis, only one fully functioning egg is formed, and the other three cells produced are non-viable polar bodies.
In some cases, errors occur during the process of meiosis. When the chromosomes do not segregate properly during meiosis, the resulting gamete ends up with too many or too few chromosomes. In most cases, the gamete or the resulting fertilized egg does not survive. Down syndrome is an example of a genetic disorder caused by an error in meiosis. Maternal age and environmental factors may contribute to meiosis errors, although in some cases errors occur simply as a result of natural inefficiencies in the process of cell division.Learn more about Molecular Biology & DNA
Meiosis is a type of cell division that reduces the number of chromosomes in the parent cell. Meiosis produces four gamete cells. Meiosis is required to produce egg and sperm cells for sexual reproduction.Full Answer >
The German doctor Rudolf Virchow proposed that all cells result from the division of previously existing cells, and this idea became a key piece of modern cell theory. Virchow also founded the discipline of cellular pathology based on the idea that diseases do not affect an entire organism but are instead localized to certain groups of cells. This made it easier to diagnose and treat diseases.Full Answer >
Cell division has three purposes for an organism: reproduction, growth and maintenance. For single-celled organisms, this is their direct and only method of reproduction, and it serves no other purpose. For multicellular organisms, cell division is a step in reproduction and is necessary for growth and maintenance.Full Answer >
The type of molecules that pass most readily through a cell membrane are nonpolar molecules, such as water, oxygen, carbon dioxide and fatty substrates. The process by which these molecules are transported across cell membranes is known as simple diffusion.Full Answer >