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Metaphase (from Ancient Greek μετα- beyond, above, transcending and from Ancient Greek φάσις (phásis) 'appearance') is a stage of mitosis in the eukaryotic cell cycle in which chromosomes are at their second-most condensed and coiled stage (they are at their most condensed in anaphase). [1]
Chromosomes at various stages of mitosis.Karyograms are generally made by chromosomes in prometaphase or metaphase. During these phases, the two copies of each chromosome (connected at the centromere) will look as one unless the image resolution is high enough to distinguish the two.
The following are a few of the diseases that can occur and be present during the process. Polyspermy results from multiple sperm fertilizing an egg, leading to an offset number of chromosomes within the embryo. [35] Polyspermy, while physiologically possible in some species of vertebrates and invertebrates, is a lethal condition for the human ...
[1] [2] These eukaryotic chromosomes display a complex three-dimensional structure that has a significant role in transcriptional regulation. [3] Normally, chromosomes are visible under a light microscope only during the metaphase of cell division, where all chromosomes are aligned in the center of the cell in their condensed form. [4]
The normal period of gestation (pregnancy) is about nine months or 40 weeks. The germinal stage refers to the time from fertilization through the development of the early embryo until implantation is completed in the uterus. The germinal stage takes around 10 days. [1] During this stage, the zygote divides in a process called cleavage.
These chromosomes have already been replicated and have two sister chromatids which are then separated during the second division of meiosis. [4] Both of these cell division cycles are used in the process of sexual reproduction at some point in their life cycle. Both are believed to be present in the last eukaryotic common ancestor.
ploidy/chromosomes chromatids Process Time of completion Oogonium: diploid/46(2N) 2C: Oocytogenesis : Third trimester: primary oocyte: diploid/46(2N) 4C: Ootidogenesis (meiosis I) (Folliculogenesis) Dictyate in prophase I for up to 50 years secondary oocyte: haploid/23(1N) 2C: Ootidogenesis (meiosis II) Halted in metaphase II until ...
The eukaryotic cell cycle consists of four distinct phases: G 1 phase, S phase (synthesis), G 2 phase (collectively known as interphase) and M phase (mitosis and cytokinesis). M phase is itself composed of two tightly coupled processes: mitosis, in which the cell's nucleus divides, and cytokinesis, in which the cell's cytoplasm and cell membrane divides forming two daughter cells.