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The centrally constricted region that forms across the central axis of a cell during cytokinesis, constricted by the closing of the contractile ring until the daughter cells are finally separated, [2] but occasionally persisting as a tether between the two cells for as long as a complete cell cycle. [8] middle lamella
The eukaryotic cell cycle consists of four distinct phases: G 1 phase, S phase (synthesis), G 2 phase (collectively known as interphase) and M phase (mitosis and cytokinesis). M phase is itself composed of two tightly coupled processes: mitosis, in which the cell's nucleus divides, and cytokinesis, in which the cell's cytoplasm and cell membrane divides forming two daughter cells.
Three types of cell division: binary fission (taking place in prokaryotes), mitosis and meiosis (taking place in eukaryotes).. When cells are ready to divide, because cell size is big enough or because they receive the appropriate stimulus, [20] they activate the mechanism to enter into the cell cycle, and they duplicate most organelles during S (synthesis) phase, including their centrosome.
In eukaryotes, the cell cycle consists of four main stages: G 1, during which a cell is metabolically active and continuously grows; S phase, during which DNA replication takes place; G 2, during which cell growth continues and the cell synthesizes various proteins in preparation for division; and the M phase, during which the duplicated ...
The physical role of the centromere is to act as the site of assembly of the kinetochores – a highly complex multiprotein structure that is responsible for the actual events of chromosome segregation – i.e. binding microtubules and signaling to the cell cycle machinery when all chromosomes have adopted correct attachments to the spindle, so ...
A cell during anaphase. Microtubules are visible in green. Stages of late M phase in a vertebrate cell. Anaphase (from Ancient Greek ἀνα-() 'back, backward' and φάσις (phásis) 'appearance') is the stage of mitosis after the process of metaphase, when replicated chromosomes are split and the newly-copied chromosomes (daughter chromatids) are moved to opposite poles of the cell.
Light micrograph of a moss's leaf cells at 400X magnification. The following outline is provided as an overview of and topical guide to cell biology: . Cell biology – A branch of biology that includes study of cells regarding their physiological properties, structure, and function; the organelles they contain; interactions with their environment; and their life cycle, division, and death.
The cell on the left is going through mitosis and its chromosomes have condensed. Cell nucleus: A cell's information center, the cell nucleus is the most conspicuous organelle found in a eukaryotic cell. It houses the cell's chromosomes, and is the place where almost all DNA replication and RNA synthesis (transcription) occur.