Why is interphase important

The synthesis phase of interphase takes the longest because of the complexity of the genetic material being duplicated. Throughout interphase, nuclear DNA remains in a semi-condensed chromatin configuration. In the S phase, DNA replication results in the formation of identical pairs of DNA molecules, sister chromatids, that are firmly attached to the centromeric region. The centrosome is duplicated during the S phase.

The two centrosomes will give rise to the mitotic spindle, the apparatus that orchestrates the movement of chromosomes during mitosis. At the center of each animal cell, the centrosomes of animal cells are associated with a pair of rod-like objects, the centrioles, which are at right angles to each other. Centrioles help organize cell division. Centrioles are not present in the centrosomes of other eukaryotic species, such as plants and most fungi. In the G 2 phase, the cell replenishes its energy stores and synthesizes proteins necessary for chromosome manipulation.

Some cell organelles are duplicated, and the cytoskeleton is dismantled to provide resources for the mitotic phase. There may be additional cell growth during G 2. The final preparations for the mitotic phase must be completed before the cell is able to enter the first stage of mitosis. Learning Objectives Describe the events that occur during Interphase.

Cells spend most of their lives in interphase, specifically in the S phase where genetic material must be copied. The cell grows and carries out biochemical functions, such as protein synthesis, in the G 1 phase. During the S phase, DNA is duplicated into two sister chromatids, and centrosomes, which give rise to the mitotic spindle, are also replicated.

Figure 3: a Metaphase and b Anaphase. In metaphase a , the microtubules of the spindle white have attached and the chromosomes have lined up on the metaphase plate.

During anaphase b , the sister chromatids are pulled apart and move toward opposite poles of the cell. Figure Detail. After metaphase is complete, the cell enters anaphase. During anaphase, the microtubules attached to the kinetochores contract, which pulls the sister chromatids apart and toward opposite poles of the cell Figure 3c. At this point, each chromatid is considered a separate chromosome.

Figure 4: During telophase, two nuclear membranes form around the chromosomes, and the cytoplasm divides. Finally, once anaphase is complete, the cell enters the last stage of the division process — telophase. During telophase, the newly separated chromosomes reach the mitotic spindle and a nuclear membrane forms around each set of chromosomes, thus creating two separate nuclei inside the same cell. As Figure 4 illustrates, the cytoplasm then divides to produce two identical cells.

Why is mitosis important? As previously mentioned, most eukaryotic cells that are not involved in the production of gametes undergo mitosis.

These cells, known as somatic cells , are important to the survival of eukaryotic organisms, and it is essential that somatic parent and daughter cells do not vary from one another. With few exceptions, the mitotic process ensures that this is the case. Therefore, mitosis ensures that each successive cellular generation has the same genetic composition as the previous generation, as well as an identical chromosome set.

Watch this historic video from to see mitosis in action. Key Questions How do centromeres work? Key Concepts chromosomes replication meiosis. Topic rooms within Genetics Close. No topic rooms are there. Browse Visually. Other Topic Rooms Genetics. Student Voices. Creature Cast.

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