Search results
Results from the WOW.Com Content Network
A cell during anaphase. Microtubules are visible in green. Stages of late M phase in a vertebrate cell. Anaphase (from Ancient Greek ἀνα-() 'back, backward' and φάσις (phásis) 'appearance') is the stage of mitosis after the process of metaphase, when replicated chromosomes are split and the newly-copied chromosomes (daughter chromatids) are moved to opposite poles of the cell.
Progression from metaphase to anaphase is marked by sister chromatid separation. The cell cycle surveillance mechanism that prevents sister-chromatid separation and transition into anaphase is called the spindle checkpoint. As a safeguard against chromosome segregation errors, the spindle assembly checkpoint (SAC) delays anaphase until all ...
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.
Anaphase is a very short stage of the cell cycle and it occurs after the chromosomes align at the mitotic plate. Kinetochores emit anaphase-inhibition signals until their attachment to the mitotic spindle. Once the final chromosome is properly aligned and attached the final signal dissipates and triggers the abrupt shift to anaphase. [26]
The rapid surge in cyclin B-Cdk1 activity is necessary, as M phase initiation is an all-or-nothing event engaging in hysteresis. Hysteresis of Cdk1 activity via cyclin B drives M phase entry by establishing a minimum threshold of cyclin B concentration.
During anaphase A, the cohesins that bind sister chromatids together are cleaved, forming two identical daughter chromosomes. [52] Shortening of the kinetochore microtubules pulls the newly formed daughter chromosomes to opposite ends of the cell. During anaphase B, polar microtubules push against each other, causing the cell to elongate. [53]
The breaking of the mitotic spindle, common to the completion of mitosis in all eukaryotes, is the event most often used to define the anaphase-B to telophase transition, [2] [6] although the initiation of nuclear reassembly tends to precede that of spindle disassembly. [11]
In some experiments, a researcher may want to control and synchronize the time when a group of cells progress to the next phase of the cell cycle. [5] The cells can be induced to arrest as they arrive (at different time points) at a certain phase, so that when the arrest is lifted (for instance, rescuing cell cycle progression by introducing another chemical) all the cells resume cell cycle ...