To put that another way, meiosis in humans is a division process that takes us from a diploid cell—one with two sets of chromosomes—to haploid cells—ones. The cell cycle. Actively dividing eukaryote cells pass through a series of stages known collectively as the cell cycle: two gap phases (G1 and G2); an S (for. Meiosis is the special type of reductive cell division occurring only in the generation of the gametes or germ cells (oocyte and spermatozoa).Introduction · Some Recent Findings · Meiosis I and II · Female Gametogenesis.
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What is meiosis? | Facts |
Ploidy is a term referring to the number of sets of chromosomes. Organisms with more than two sets of chromosomes meiotic cell division termed polyploid. Chromosomes that carry the same genes are termed homologous chromosomes. The alleles on homologous chromosomes may differ, as in the case of heterozygous individuals.
Organisms normally receive one set of homologous chromosomes from each parent. Meiosis is a special type of nuclear division meiotic cell division segregates one copy of each homologous chromosome into each new "gamete".
CELL DIVISION: Meiosis
Mitosis maintains the cell's original ploidy level for example, one diploid 2n cell producing two diploid 2n cells; one haploid n cell producing two haploid n cells; etc. Meiosis, on the other hand, reduces the number of sets of chromosomes by half, so that when gametic recombination fertilization occurs the ploidy of the parents will be reestablished.
meiotic cell division
Most cells in the human body are produced by mitosis. These are the somatic or vegetative line cells.
Cells that become gametes are referred to as germ line cells. The chromosomes continue to condense.
Metaphase The chromosomes align themselves along the metaphase plate of the spindle apparatus. Anaphase The shortest stage of mitosis.
The Cell Cycle, Mitosis and Meiosis
The centromeres divide, and the sister chromatids of each chromosome are pulled apart - or 'disjoin' - and move to the opposite ends of the cell, pulled by spindle fibres attached to the kinetochore regions.
The separated sister chromatids are now referred to as daughter chromosomes. It meiotic cell division the alignment and separation in metaphase and anaphase that is important in ensuring that each daughter cell receives a copy of every chromosome.
Telophase The final stage of mitosis, and a reversal of many of the processes observed during prophase. The nuclear membrane reforms around meiotic cell division chromosomes grouped at either pole of the cell, the chromosomes uncoil and become diffuse, and the spindle fibres disappear.
Cytokinesis The final cellular division to form meiotic cell division new cells.
meiotic cell division In plants a cell plate forms along the line of the metaphase plate; in animals there is a constriction of the cytoplasm. The cell then enters interphase - the interval between mitotic divisions.
Meiosis: Meiotic cell division, stages and significance
Meiosis Meiosis is the form of eukaryotic cell division that produces haploid sex cells or gametes which contain a single copy of each chromosome from diploid cells which contain two copies of each chromosome. As in mitosis, meiosis is preceded by a process of DNA replication that converts each chromosome into two sister chromatids.
The membrane around the nucleus in each daughter cell dissolves away meiotic cell division the meiotic cell division. The meiotic spindle forms again. In each of the two daughter cells meiotic cell division chromosomes pair of sister chromatids line up end-to-end along the equator of the cell.
The centrioles are now at opposites poles in each of the daughter cells.