In rapidly dividing human cells with a 24-hour cell cycle, the G1 phase lasts approximately 11 hours. The length of the cell cycle is highly variable even within the cells of an individual organism. a. prophase b. prometaphase c. metaphase d. anaphase e. telophase, In what phase of meiosis does an independent assortment of homologous chromosomes occur? compact than they were during interphase. A precise estimate of the difference is not possible, but during interphase, chromatin may be hundreds or even thousands of times less condensed than it is during mitosis. Cohesin is retained, however, at the most constricted part of the chromosome, the centromere (Figure 9). Select one: a. prophase II b. metaphase II c. anaphase I d. metaphase I e. prophase I. For the most part, only cells that have successfully copied their DNA will proceed into mitosis. Polar fibers (microtubules that make up the spindle fibers) continue to extend from the poles to the center of the cell. The daughter cells that result from this process have identical genetic compositions. Boveri observed that the spindle fibers radiate from structures at each pole that we now recognize as centrosomes, and he also noted that each centrosome contains two small, rodlike bodies, which are now known as centrioles. The cleavage furrow forms because of the action of a contractile ring of overlapping actin and myosin filaments. The kinetochore becomes attached to metaphase plate. Since cell division occurs twice during meiosis, one starting cell can produce four gametes (eggs or sperm). Bailey, Regina. a. metaphase II b. anaphase II c. anaphase I d. metaphase I e. prophase, When the chromosomes line up in mitosis, this is known as which phase? Our experts can answer your tough homework and study questions. Telophase I: Newly forming cells are haploid, n = 2. The G1 checkpoint, also called the restriction point, is the point at which the cell irreversibly commits to the cell-division process. Prophase Mitosis = duplication of the cell's chromosomes, after which two identical cells are formed, so not whole individuals. This may seem familiar from mitosis, but there is a twist. During which stage do Homologous chromosomes separate and move towards opposite poles? The kinetochore fibers "interact" with the spindle polar fibers connecting the kinetochores to the polar fibers. Direct link to Julia Nilsson's post In plant cells, the first, Posted 8 years ago. The spindle forms. Mitosis is the process in which a eukaryotic cell nucleus splits in two, followed by division of the parent cell into two daughter cells.