What are the most common phase(s) in mitosis?

Question

What does the difference in numbers of cells might mean in each phase?

Answer 1

Prophase - nucleus is dissolved, chromatin condenses into chromasomes - mitotic spindle forms
Metaphase - chromasomes align in the center of the cell
Anaphase - chromasomes separate at the centromere and move to opposite poles of the cell
Telophase - new nuclear envelope forms around chromasomes
Cytokinesis - division of the cytoplasm (can sometimes be considered part of telophase)

Answer 2

There isnt really a difference between teh numbers of cells in each phase. The end phase, telophase, will always ahve one more cell than the start phase, G1 phase or whatever. In meiosis its three more than the start. YOu need to respecify your question a little bit. The number of cells in each phase has to do with when they are truly "born"

Answer 3

Mitotic Stage

Answer 4

You will enjoy reading this very informative article with pictures and diagrams.


[Observing Mitosis with Fluorescence Microscopy]

Answer 5

Interphase is the stage that a cell will remain until either it is required to divide or if it is required to divide, if the cell has the right components to divide. So each cell spends most of its time in interphase.

Answer 6

Phases of mitosis
The mitotic phase is a relatively short action-packed period of the cell cycle. It alternates with the much longer interphase, where the cell prepares itself for division. Interphase is divided into three phases, G1 (first gap), S (synthesis), and G2 (second gap). During all three phases, the cell grows by producing proteins and cytoplasmic organelles. However, chromosomes are replicated only during the S phase. Thus, a cell grows (G1), continues to grow as it duplicates its chromosomes (S), grows more and prepares for mitosis (G2), and divides (M).

Mitosis is a continual and dynamic process. For purposes of description, however, mitosis is conventionally broken down into five subphases: prophase, prometaphase, metaphase, anaphase, and telophase.

Prophase
Normally, the genetic material in the nucleus is in a loosely bundled coil called chromatin. At the onset of prophase, chromatin condenses together into a highly ordered structure called a chromosome. Since the genetic material has already been duplicated earlier in S phase, the chromosomes have two sister chromatids, bound together at the centromere by the protein cohesin. Chromosomes are visible at high magnification through a light microscope.

Just outside the nucleus are two centrosomes. Each centrosome, which was replicated earlier independent of mitosis, acts as a coordinating center for the cell's microtubules. The two centrosomes sprout microtubules (which may be thought of as cellular ropes or poles) by polymerizing free-floating tubulin protein. By repulsive interaction of these microtubules with each other, the centrosomes push themselves to opposite ends of the cell (although new research has shown that there might be a mechanism inside the centromeres that also grab the microtubules and pull the chromatids apart). The network of microtubules is the beginning of the mitotic spindle.

Some centrosomes contain a pair of centrioles that may help organize microtubule assembly, but they are not essential to formation of the mitotic spindle. Plant cells that lack centrioles have no trouble undergoing mitosis.

Prometaphase
The nuclear envelope dissolves and microtubules invade the nuclear space. This is called open mitosis, and it occurs in most multicellular organisms. Some protists, such as algae, undergo a variation called closed mitosis where the microtubules are able to penetrate an intact nuclear envelope.

Each chromosome forms two kinetochores at the centromere, one attached at each chromatid. A kinetochore is a complex protein structure that is analogous to a ring for the microtubule hook; it is the point where microtubules attach themselves to the chromosome. Although the kinetochore is not fully understood, it is known that it contains a molecular motor. When a microtubule connects with the kinetochore, the motor activates, using energy from ATP to "crawl" up the tube toward the originating centrosome. The kinetochore provides the pulling force necessary to later separate the chromosome's two chromatids.

When the spindle grows to sufficient length, kinetochore microtubules begin searching for kinetochores to attach to. A number of nonkinetochore microtubules find and interact with corresponding nonkinetochore microtubules from the opposite centrosome to form the mitotic spindle. Prometaphase is sometimes considered part of prophase.

Metaphase
As microtubules find and attach to kinetochores in prometaphase, the centromeres of the chromosomes convene along the metaphase plate or equatorial plane, an imaginary line that is equidistant from the two centrosome poles. This even alignment is due to the counterbalance of the pulling powers generated by the opposing kinetochores, analogous to a tug of war between equally strong people. In certain types of cells, chromosomes do not line up at the metaphase plate and instead move back and forth between the poles randomly, only roughly lining up along the midline.

Because proper chromosome separation requires that every kinetochore be attached to a bundle of microtubules, it is thought that unattached kinetochores generate a signal to prevent premature progression to anaphase without all chromosomes being aligned. The signal creates the mitotic spindle checkpoint.

Anaphase
When every kinetochore is attached to a cluster of microtubules and the chromosomes have lined up along the metaphase plate, the cell proceeds to anaphase. Two events occur in order:
1. The proteins that bind sister chromatids together are cleaved, allowing them to separate. These sister chromatids turned sister chromosomes are pulled apart by shortening kinetochore microtubules and toward the respective centrosomes to which they are attached.
2. The nonkinetochore microtubules elongate, pushing the centrosomes (and the set of chromosomes to which they are attached) apart to opposite ends of the cell.

These two stages are sometimes called early and late anaphase. At the end of anaphase, the cell has succeeded in separating identical copies of the genetic material into two distinct populations.

Telophase
Telophase is a reversal of prophase and prometaphase events. It "cleans up" the aftereffects of mitosis. At telophase, the nonkinetochore microtubules continue to lengthen, elongating the cell even more. Corresponding sister chromosomes attach at opposite ends of the cell. A new nuclear envelope, using fragments of the parent cell's nuclear membrane, forms around each set of separated sister chromosomes. Both sets of chromosomes, now surrounded by new nuclei, unfold back into chromatin.

Cytokinesis
Often (mistakenly) thought to be the same process as telophase, cytokinesis, if slated to occur, is usually well under way by this time. In animal cells, a cleavage furrow develops where the metaphase plate used to be, pinching off the separated nuclei. In plant cells, vesicles derived from the Golgi apparatus move along microtubules to the middle of the cell, coalescing into a cell plate that develops into a cell wall, separating the two nuclei. Each daughter cell has a complete copy of the genome of its parent cell. Mitosis is complete.

Errors in mitosis
Although errors in mitosis are rare, the process may go wrong, especially during early cellular divisions in the zygote. Mitotic errors can be especially dangerous to the organism because future offspring from this parent cell will carry the same disorder.

In non-disjunction, a chromosome may fail to separate during anaphase. One daughter cell will receive both sister chromosomes and the other will receive none. This results in the former cell having three chromosomes coding for the same thing (two sisters and a homologous), a condition known as trisomy, and the latter cell having only one chromosome (the homologous chromosome), a condition known as monosomy. These cells are considered aneuploidic cells. Aneuploidy can cause cancer.

Mitosis is a traumatic process. The cell goes through dramatic changes in ultrastructure, its organelles disintegrate and reform in a matter of hours, and chromosomes are jostled constantly by probing microtubules. Occasionally, chromosomes may become damaged. An arm of the chromosome may be broken and the fragment lost, causing deletion. The fragment may incorrectly reattach to another, non-homologous chromosome, causing translocation. It may reattach to the original chromosome, but in reverse orientation, causing inversion. Or, it may be treated erroneously as a separate chromosome, causing chromosomal duplication. The effect of these genetic abnormalities depend on the specific nature of the error. It may range from no noticeable effect at all to organism death.

You could get more information from the link below...

Answer 7

telophase