#Cell cycle mitosis flip book series#

Enzymes use the glucose that has accumulated between the membrane layers to build a new cell wall. As more vesicles fuse, the cell plate enlarges until it merges with the cell walls at the periphery of the cell. There, the vesicles fuse and coalesce from the center toward the cell walls this structure is called a cell plate. During telophase, these Golgi vesicles are transported on microtubules to form a phragmoplast (a vesicular structure) at the metaphase plate. During interphase, the Golgi apparatus accumulates enzymes, structural proteins, and glucose molecules prior to breaking into vesicles and dispersing throughout the dividing cell. In plant cells, a new cell wall must form between the daughter cells.

A cell plate formed by the fusion of the vesicles of the phragmoplast grows from the center toward the cell walls, and the membranes of the vesicles fuse to form a plasma membrane that divides the cell in two. In plant cells, Golgi vesicles coalesce at the former metaphase plate, forming a phragmoplast. The ring contracts, forming a cleavage furrow, which divides the cell in two. During cytokinesis in animal cells, a ring of actin filaments forms at the metaphase plate. The furrow deepens as the actin ring contracts, and eventually the membrane is cleaved in two (Figure 4). This fissure, or “crack,” is called the cleavage furrow. The actin filaments pull the equator of the cell inward, forming a fissure. A contractile ring composed of actin filaments forms just inside the plasma membrane at the former metaphase plate. In cells such as animal cells that lack cell walls, cytokinesis follows the onset of anaphase. Although the stages of mitosis are similar for most eukaryotes, the process of cytokinesis is quite different for eukaryotes that have cell walls, such as plant cells. Division is not complete until the cell components have been apportioned and completely separated into the two daughter cells. The activity below will walk you through mitosis-providing you with the chance to review the different steps of the process and how they work together.Ĭytokinesis is the second main stage of the mitotic phase during which cell division is completed via the physical separation of the cytoplasmic components into two daughter cells. Nuclear envelopes form around the chromosomes, and nucleosomes appear within the nuclear area. The cell becomes visibly elongated (oval shaped) as the polar microtubules slide against each other at the metaphase plate where they overlap.ĭuring telophase, the chromosomes reach the opposite poles and begin to decondense (unravel), relaxing into a chromatin configuration. Each chromatid, now called a chromosome, is pulled rapidly toward the centrosome to which its microtubule is attached. At this time, the chromosomes are maximally condensed.ĭuring anaphase, the sister chromatids separate at the centromere. Eventually, all the sister chromatids will be attached via their kinetochores to microtubules from opposing poles.ĭuring metaphase, all the chromosomes are aligned in a plane called the metaphase plate, or the equatorial plane, midway between the two poles of the cell. Once a mitotic fiber attaches to a chromosome, the chromosome will be oriented until the kinetochores of sister chromatids face the opposite poles. The proteins of the kinetochore attract and bind mitotic spindle microtubules.ĭuring prometaphase, the nuclear envelope is fully broken down and chromosomes are attached to microtubules from both poles of the mitotic spindle, which begin to move them toward the middle of the cell. Each sister chromatid develops a protein structure called a kinetochore in the centromeric region (Figure 3). The sister chromatids begin to coil more tightly and become visible under a light microscope. Microtubules that will form the mitotic spindle extend between the centrosomes, pushing them farther apart as the microtubule fibers lengthen.

The centrosomes begin to move to opposite poles of the cell. Stages of mitosisĭuring prophase, the “first phase,” the nuclear envelope starts to dissociate into small vesicles, and the membranous organelles fragment and disperse toward the periphery of the cell.

#Cell cycle mitosis flip book series#

Karyokinesis, also known as mitosis, is divided into a series of phases-prophase, metaphase, anaphase, and telophase-that result in the division of the cell (Figure 2).