DNA replication occurs only during a specific stage of the cell cycle. But the replication of each eukaryotic DNA molecule is similar to replication in prokaryotes, in that it is achieved by threading the long strands through replication complexes (see Concept 9.2). Unlike prokaryotes, eukaryotes have more than one chromosome. We will discuss the signals that control eukaryotic cell division in Concept 7.3. In a eukaryotic organism, the signals for cell division are usually not related to the environment of a single cell, but to the function of the entire organism. In fact, most cells in a multicellular organism are specialized and do not divide. Unlike prokaryotes, eukaryotic cells do not constantly divide whenever environmental conditions are adequate. Some of the details, however, are quite different: Let’s see how these events occur during the processes of binary fission in prokaryotes and mitosis in eukaryotes.Įukaryotic cells divide by mitosis followed by cytokinesisĪs in prokaryotes, cell division in eukaryotes entails reproductive signals, DNA replication, DNA segregation, and cytokinesis. The cytoplasm must divide to form the two new cells, each surrounded by a cell membrane and a cell wall in organisms that have one.The cell must distribute the replicated DNA to each of the two new cells.DNA replication (i.e., replication of the genetic material) must occur so that each of the two new cells will have a full complement of genes to complete cell functions.These signals initiate cell division and may originate from either inside or outside the cell. There must be one or more reproductive signals.In order for any cell to divide, the following events must occur: In multicellular organisms, mitosis is a way to build tissues and organs during development and to repair damaged tissues once development is complete. This is the basis of asexual reproduction in single-celled organisms: prokaryotes reproduce by binary fission, and single-celled eukaryotes reproduce by mitosis. Concept 7.2: Both Binary Fission and Mitosis Produce Genetically Identical CellsĬell division by either binary fission or mitosis produces two genetically identical cells.
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