Search results
Results from the WOW.Com Content Network
The spindle checkpoint, also known as the metaphase-to-anaphase transition, the spindle assembly checkpoint (SAC), the metaphase checkpoint, or the mitotic checkpoint, is a cell cycle checkpoint during metaphase of mitosis or meiosis that prevents the separation of the duplicated chromosomes until each chromosome is properly attached to the ...
These chromosomes, carrying genetic information, align in the equator of the cell between the spindle poles at the metaphase plate, before being separated into each of the two daughter nuclei. This alignment marks the beginning of metaphase. [2] Metaphase accounts for approximately 4% of the cell cycle's duration. [citation needed]
Micrograph showing condensed chromosomes in blue, kinetochores in pink, and microtubules in green during metaphase of mitosis. In cell biology, the spindle apparatus is the cytoskeletal structure of eukaryotic cells that forms during cell division to separate sister chromatids between daughter cells.
Metaphase: The centrosomes have moved to the poles of the cell and have established the mitotic spindle. The chromosomes have congressed at the metaphase plate. The chromosomes have congressed at the metaphase plate.
Astral microtubules anchor the spindle poles to the cell membrane. Microtubule polymerization is nucleated at the microtubule organizing center . An aster is a cellular structure shaped like a star , consisting of a centrosome and its associated microtubules during the early stages of mitosis in an animal cell.
As metaphase begins, the spindle checkpoint inhibits the APC/C until all sister-kinetochores are attached to opposite poles of the mitotic spindle, a process known as chromosome biorientation. When all kinetochores are properly attached, the spindle checkpoint is silenced and the APC/C can become active.
The spindle checkpoint, or SAC (for spindle assembly checkpoint), also known as the mitotic checkpoint, is a cellular mechanism responsible for detection of: correct assembly of the mitotic spindle; attachment of all chromosomes to the mitotic spindle in a bipolar manner; congression of all chromosomes at the metaphase plate.
Researchers have detached grasshopper spermatocytes from spindle fibers and moved them away from the metaphase plate via micromanipulation. Several chromosomes instantly bioriented, as deduced from the observation that, upon reattachment, the chromosomes moved to the metaphase plate without moving to the poles. [4]