Cell division, cell diversity and cell organisation GapFill

The  genetic sequencecell structurecell cycleDNA circle is used to determine when eukaryotic cells divide and when they grow. It has three main stages:

Mitosis has several distinct stages which can be recognised by studying the behaviour of the genetic material.

 MagnificationMeiosisMitosisPolymerisation consists of two rounds of mitotic division, and contributes to increasing genetic diversity. In  chromophase 1interphasetelophase 1prophase 1, chromosomes condense, the  cytoplasmcell-surface membranemitochondrionnuclear envelope breaks down and spindle fibres form. During  anaphase 1centrophase 1interphasemetaphase 1, spindle fibres align the homologous chromosomes along the centre of the cell, and one chromosome from each pair is pulled to opposite poles of the cell in  anaphase 1telophase 1metaphase 1cytokinesis. This is known as independent assortment of homologous chromosomes, and means that daughter cells contain different combinations of maternal and paternal genes.  Crossing overCo-transversionFacilitated diffusionSwitching sides can also result in recombination of alleles to produce non-identical daughter cells. In  anaphase 2telophase 2prophase 2interphase after the second division and separation, chromatids disperse into  geneschromatinglycolipidsalleles, spindle fibres disintegrate and the nuclear envelope reforms.

Although every body cell arises from a single zygote and contains the same genetic information, differentiation can occur in multicellular organisms, which often have specialised cells, such as ciliated epithelia, to overcome their low  water potentialsurface-area-to-volume ratiopHintracellular pressure. Similar cells with a common function (such as palisade meosphyll cells) work together as  nervesglandstissuesvessels, several of which can form an organ (such as a leaf). Organs which work together are called organ systems. Some  hormonesgenesimpulseschromatids are not expressed in some cell types, as not all the DNA is translated in every cell. Other cells retain the ability to divide, self-renew and produce more than one cell type throughout their life. These are known as  plural cellspolypotent cellsstem cellsphagocytic cells and are important tools in medicine as they can be used to regrow tissues or repair damage resulting from injury or disease.