Anaphase – The stage preceding telophase, in which the chromosomes are segregated.Telomere – The repeating ends of DNA strands, which help protect the DNA when it is moved around.Cytokinesis – The final process that concludes cell division, separate from telophase.Between the four cells produced at the end of meiosis, the two alleles for each gene can be segregated in many different ways, in combination with alleles for many other genes. Although the two cells created during telophase II come from the same chromosome that has been duplicated, variation can be introduced in the process of recombination, in which parts of homologous chromosomes were exchanged in prophase I. During telophase II, the sister chromosomes are surrounded by new nuclear membranes. Telophase IIĭuring the subsequent cell division, the sister chromatids of each chromosome are separated.
The cells then enter a short resting stage, known as interkinesis. Although another division must take place for meiosis to be complete, the cells must still reform the nuclear envelopes, disassemble the spindle fiber microtubules, and go through cytokinesis. During telophase I, the homologous chromosomes get segregated into separate nuclei. Meiosis contains two divisions, both of which contain a telophase stage. Meiosis, on the other hand, produces cells that differ in the genetics they carry. These cells will function in the same way, and can be used to build entire organisms from a single zygote, or replace cells which have been damaged. Thus, during telophase two identical nuclei are created. The remainder of the microtubules will function in cytokinesis, which will fully separate the two cells.ĭuring mitosis, each duplicated chromosome is evenly divided. The tubulin dimers fall apart, and much of the microtubule network is disassembled. The mitotic spindle is no longer necessary because the chromosomes completed their journey. The sister chromosomes, once sister chromatids, have now been segregated to the far poles of the cell. Other microtubules, which will function during cytokinesis, stay intact. The dimers break apart, and the entire structure falls to pieces. During telophase, cellular signals are given out which tell certain spindle microtubules to disassociate from each other. The dimers combine together to form much larger tubes, which form the structure of most cellular forms. These monomers combine together to create tubulin dimers. Microtubules are formed from two different subunits, α-tubulin and β-tubulin, as seen in the picture below. The final step in telophase is for the complex array of microtubules to degrade. Once this complex is reformed in the new nuclei during telophase, the cells (still attached) can begin producing proteins from the newly synthesized genetic code. Ribosomes are the small protein structures that create many types of protein. The nucleolus is a dense complex of enzymes, RNA, and DNA, which creates ribosomes. Once this nuclear envelope is reformed, the chromosomes in the nucleus can begin to unwind back into chromatin and the nucleolus can reform. Either way, the nuclear envelope is reformed around each nucleus. The other theory suggests that the endoplasmic reticulum, with the old nuclear membrane processed within it, fold around the bundled chromosomes. In this theory, each vesicle of broken down nuclear membrane receives a signal to connect to the other vesicles. One theory suggests that the pieces of the nuclear envelope reform like monomers of a larger polymer that must be activated to form. The process for how this happens is still in theory. In order to allow the new cells to begin producing the necessary proteins and to protect the DNA, a nucleus must reform in each cell. When the chromosomes reach the pole for which they are intended, telophase can begin. During anaphase, the chromosomes or chromatids on the metaphase plate are separated, and dragged towards opposite poles. Telophase is ended by a process known as cytokinesis, which cleaves the cell into two new cells. As telophase moves towards completion, the chromosomes release from their tightly bound structure back into loose chromatin. As the cell has finished moving the chromosomes, the main parts of the spindle apparatus fall depolymerize, or fall apart. The nucleolus, or ribosome producing portions of the nucleus return. During telophase, the nuclear envelopes reform around the new nuclei in each half of the dividing cell. Telophase is the final stage in cell division.
0 kommentar(er)
