Cell growth
... mitosis or a more complex process called
meiosis . Mitosis and
meiosis are sometimes called the two " nuclear division" ... same number of chromosomes as the parental cell.
meiosis is used for a special cell reproduction process ...
Meiosis
... For the article on the figure of speech , see
meiosis (figure of speech) .
Overview of the major events in
meiosis
meiosis (a Greek word meaning "decrease") is a ...
Nondisjunction
... of a chromosome to split correctly during
meiosis .
This results in the production of gametes ... or monosomy .
Nondisjunction can occur in the
meiosis I or
meiosis II phases of cellular reproduction.
This is a ...
Cell division
... of the cell, called cytokinesis . A diploid cell may also undergo
meiosis to produce haploid cells, usually four. Haploid cells serve as ...
Cell growth
External link
How Cells Divide: Mitosis vs.
meiosis
...
Mitosis
... for instance among the fungi . There is another process called
meiosis , which is similar to mitosis in many ways, in which the daughter nuclei ... and the cells as endoploid.
See also
Genetics
meiosis
Cell cycle
Daughter cell
...
Mitosis
... for instance among the fungi . There is another process called
meiosis , which is similar to mitosis in many ways, in which the daughter nuclei ... and the cells as endoploid.
See also
Genetics
meiosis
Cell cycle
Daughter cell
...
Anaphase
... Anaphase ( Greek : ανά = up and φάσις = stage) is the stage of
meiosis or mitosis when chromosomes separate. Each chromatid moves to opposite poles of the cell (opposite ends of the nuclear spindle ).
Anaphase ...
Chromatid
... A chromatid forms one part of a chromosome after it has coalesced for the process of mitosis or
meiosis . Each chromosome consists of two exactly identical (" sister ") chromatids. After they have been pulled apart by the mitotic spindle , chromatids ...
Chromosome
... sets of chromosomes), and gametes (reproductive cells) which are haploid [n] (they have only one set of chromosomes). Gametes are produced by
meiosis of a diploid germ line cell. During meiosis, the matching chromosomes of father and mother can exchange small parts of themselves ( crossover ), ...
Classical genetics
... . A key discovery of classical genetics in eukaryotes , was genetic linkage . The observation that some genes do not segregate independently at
meiosis , broke the laws of Mendelian inheritance , and provided science with a way to map characteristics to a location on the chromosomes . Linkage maps ...
Chromosomal crossover
... Chromosomal crossover is the process by which two chromosomes , paired up during Prophase I of
meiosis , exchange some distal portion of their DNA . Crossover occurs when two chromosomes , normally two homologous instances of the same chromosome, ...
Ploidy
... haploid sex cells that can combine to form a diploid zygote , for example animals are primarily diploid but produce haploid gametes . During
meiosis , germ cell precursors have their number of chromosomes halved by randomly "choosing" one homologue, resulting in haploid germ cells ( sperm and ...
Evolution
... cell division and by exposure to radiation , chemicals, or viruses , or can occur deliberately under cellular control during processes such as
meiosis or hypermutation . In multicellular organisms, mutations can be subdivided into germline mutations, which can be passed on to progeny and ...
Eukaryote
... where only one copy of each chromosome is present, and diploid generations, where two are present, occurring through nuclear fusion (syngamy) and
meiosis . There is considerable variation in this pattern, however.
Origin and evolution
The origin of the eukaryotic cell was a milestone in the ...
Gamete
... into a mature individual capable of producing gametes. Gametes from a mature diploid individual will be produced in the gonadal tissue through
meiosis —a process of cellular division that reduces the number of sets of chromosomes from two to one (i.e., produces haploid gametes).
The ...
Genetic recombination
... 3 See also
4 References
Crossing over
Main article: Chromosomal crossover
Crossing over of two chromosomes occurs during
meiosis . After chromosomal replication , the four available chromatids are in tight formation with one another. During this time, homologous sites on ...
Ploidy
... haploid sex cells that can combine to form a diploid zygote , for example animals are primarily diploid but produce haploid gametes . During
meiosis , germ cell precursors have their number of chromosomes halved by randomly "choosing" one homologue, resulting in haploid germ cells ( sperm and ...
Mitotic spindle
... The mitotic spindle is a structure of the eukaryotic cytoskeleton involved in mitosis and
meiosis . It consists of a bundle of microtubules joined at the ends but spread out in the middle, vaguely resembling an American football in shape. The ...
Molecular evolution
... division and by exposure to radiation , chemicals, or viruses , or can occur deliberately under cellular control during the processes such as
meiosis or hypermutation . Mutations are considered the driving force of evolution , where less favorable (or deleterious ) mutations are removed from ...
Modern evolutionary synthesis
... mutation (this is now known to be due to mistakes in DNA replication ) and recombination (crossing over of homologous chromosomes during
meiosis ). Evolution consists primarily of changes in the frequencies of alleles between one generation and another as a result of genetic drift , gene ...
Recombination
... (or change of phase ).
Other possible implication of the term are as follows:
In biology , the process of Genetic recombination and
meiosis , as summarized above.
In chemistry and electrical engineering , it is the state in which the hydrogen and oxygen gases form within the ...
Species
... clear, the two populations are regarded as separate species.
See also microspecies under apomixis , for species that reproduce without
meiosis or mitosis so that each generation is genetically identical to the previous generation.
In practice, these definitions often coincide, and the ...
Spermatid
... The term spermatid refers to the haploid male germ cell that results from secondary spermatocyte division. As a result of
meiosis , each spermatid contains only half of the genetic material present in the original primary spermatocyte.
When formed, early round spermatids ...
Spermatogenesis
... Sperm cells develop initially from germ stem cells known as spermatogonia . As these differentiate they become spermatocytes , spermatids (after
meiosis ) and then finally the fully mature spermatozoa.
The female counterpart to spermatogenesis is oogenesis .
The process of spermatogenesis is ...