Gap 2 Phase The last part of interphase is called the G2 phase. The cell has grown, DNA has been replicated, and now the cell is almost ready to divide. This last stage is all about prepping the cell for mitosis or meiosis. During G2, the cell has to grow some more and produce any molecules it still needs to divide. The stages of interphase are: G1 Gap 1 , in which the cell grows and functions normally. During this time, a high amount of protein synthesis occurs and the cell grows to about double its original size — more organelles are produced and the volume of the cytoplasm increases.
In this section, we will discuss the breakdown of the durations of mitosis, G1, S phase, and G2 for the general 24 hour cell cycle found in most cells. As we discussed in the previous section, the lengths of G1 and G2 vary in cells based on the individual cell's level of preparedness for proceeding in the cell cycle. Remember, cells can enter G0 for extensive amounts of time during G1 before continuing on to S phase.
If a cell has quickly undergone sufficient cell growth or DNA replication, the time spent in G1 and G2 will be decreased. G1 is typically the longest phase of the cell cycle. This can be explained by the fact that G1 follows cell division in mitosis; G1 represents the first chance for new cells have to grow. Cells usually remain in G1 for about 10 hours of the 24 total hours of the cell cycle.
The length of S phase varies according to the total DNA that the particular cell contains; the rate of synthesis of DNA is fairly constant between cells and species. Microtubules that will form the mitotic spindle extend between the centrosomes, pushing them farther apart as the microtubule fibers lengthen.
The sister chromatids begin to coil more tightly and become visible under a light microscope. Each sister chromatid develops a protein structure called a kinetochore in the centromeric region Figure 3. The proteins of the kinetochore attract and bind mitotic spindle microtubules.
During 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.
Figure 3. Once a mitotic fiber attaches to a chromosome, the chromosome will be oriented until the kinetochores of sister chromatids face the opposite poles. Eventually, all the sister chromatids will be attached via their kinetochores to microtubules from opposing poles.
During 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. At this time, the chromosomes are maximally condensed. During anaphase , the sister chromatids separate at the centromere. Each chromatid, now called a chromosome, is pulled rapidly toward the centrosome to which its microtubule is attached. The cell becomes visibly elongated oval shaped as the polar microtubules slide against each other at the metaphase plate where they overlap.
During telophase , the chromosomes reach the opposite poles and begin to decondense unravel , relaxing into a chromatin configuration. Nuclear envelopes form around the chromosomes, and nucleosomes appear within the nuclear area. 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.
Click here for a text-only version of the activity. Cytokinesis 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. Division is not complete until the cell components have been apportioned and completely separated into the two daughter cells.
Simply so, what is the longest phase of the cell cycle? Answer and Explanation: The interphase is the longest phase of the cell cycle because it is the stage during which all the preparation for cell division takes place.
Mitosis is a process where a single cell divides into two identical daughter cells cell division. During mitosis one cell? The major purpose of mitosis is for growth and to replace worn out cells. Interphase is the longest phase of the cell cycle. During this phase the cell grows to its maximum size, performs its normal cellular functions, replicates its DNA, and prepares for cell division. Which stage of mitosis takes the longest?
Cell division does not take a long time. Prophase is the longest phase of mitosis, but it occurs faster than interphase. Anaphase is the shortest phase of mitosis. In anaphase, the sister chromatids are pulled apart to opposite ends of the cell.
What phase of the cell cycle is the shortest? The mitotic phase includes both mitosis and cytokinesis which is usually the shortest part of the cell cycle.
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