Meiosisis a form of cell division that to reduce the variety of chromosomes in the parentcell by half and produces 4 gamete cells. This procedure is compelled toproduce egg and also sperm cell for sex-related reproduction. During reproduction, when sperm and also egg hold together to kind a single cell, the variety of chromosomes isrestored in the offspring.
Meiosisbegins with a parental cell that is diploid, an interpretation it has two copies of eachchromosome. The parent cell undergoes one round of DNA replication complied with bytwo separate cycles of nuclear division. The procedure results in 4 daughtercells that are haploid, which way they contain fifty percent the number of chromosomesof the diploid parental cell.
Meiosishas both similarity to and differences from mitosis, which is a cabinet divisionprocess in i beg your pardon a parental cell produces two similar daughter cells. Meiosisbegins complying with one round of DNA replication in cell in the male or femalesex organs. The procedure is break-up into meiosis I and also meiosis II, and also bothmeiotic divisions have many phases. Meiosis i is a type of cabinet divisionunique come germ cells, when meiosis II is comparable to mitosis.
MeiosisI, the an initial meiotic division, begins with prophase I. Throughout prophase I, thecomplex of DNA and also protein known as chromatin condenses to type chromosomes.The bag of replicated chromosomes are well-known as sisters chromatids, and theyremain join at a central point called the centromere. A large structurecalled the meiotic spindle additionally forms from long proteins referred to as microtubules oneach side, or pole, that the cell. In between prophase I and metaphase I, the pairsof homologous chromosome type tetrads. In ~ the tetrad, any kind of pair of chromatidarms deserve to overlap and also fuse in a procedure called crossing-over or recombination.Recombination is a process that breaks, recombines and rejoins part of DNAto produce brand-new combinations the genes. In metaphase I, the homologous bag ofchromosomes align top top either side of the equatorial plate. Then, in anaphase I,the spindle fibers contract and also pull the homologous pairs, each through twochromatids, far from each other and toward every pole that the cell. Duringtelophase I, the chromosomes are enclosed in nuclei. The cell currently undergoes aprocess referred to as cytokinesis the divides the cytoplasm that the initial cell intotwo daughter cells. Every daughter cell is haploid and also has just one collection ofchromosomes, or half the total variety of chromosomes of the original cell.
MeiosisII is a mitotic division of every of the haploid cells produced in meiosis I.During prophase II, the chromosomes condense, and a new set that spindle fibersforms. The chromosomes begin moving towards the equator of the cell. Duringmetaphase II, the centromeres of the combine chromatids align along theequatorial plate in both cells. Climate in anaphase II, the chromosomes separateat the centromeres. The spindle fibers pull the separated chromosomes towardeach pole of the cell. Finally, throughout telophase II, the chromosomes areenclosed in nuclear membranes.
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Cytokinesis follows, dividing the cytoplasm ofthe 2 cells. At the conclusion the meiosis, there are four haploid daughtercells the go top top to build into either sperm or egg cells.