When is dna copied in mitosis

What is a genome? What is DNA? What is a cell? How helpful was this page? What's the main reason for your rating? Which of these best describes your occupation? What is the first part of your school's postcode? How has the site influenced you or others? Most cells grow, perform the activities needed to survive, and divide to create new cells. These basic processes, known collectively as the cell cycle , are repeated throughout the life of a cell. Of the various parts of the cell cycle, the division portion is particularly important, because this is the point at which a cell passes its genetic information to its offspring cells.

In many situations, division also ensures that new cells are available to replace the older cells within an organism whenever those cells die. Prokaryotic cells, which include bacteria, undergo a type of cell division known as binary fission. This process involves replication of the cell's chromosomes, segregation of the copied DNA, and splitting of the parent cell's cytoplasm.

The outcome of binary fission is two new cells that are identical to the original cell. In contrast to prokaryotic cells, eukaryotic cells may divide via either mitosis or meiosis. Of these two processes, mitosis is more common. In fact, whereas only sexually reproducing eukaryotes can engage in meiosis, all eukaryotes — regardless of size or number of cells — can engage in mitosis. But how does this process proceed, and what sorts of cells does it produce?

During mitosis, a eukaryotic cell undergoes a carefully coordinated nuclear division that results in the formation of two genetically identical daughter cells. Mitosis itself consists of five active steps, or phases: prophase, prometaphase, metaphase, anaphase, and telophase. Before a cell can enter the active phases of mitosis, however, it must go through a period known as interphase , during which it grows and produces the various proteins necessary for division.

Then, at a critical point during interphase called the S phase , the cell duplicates its chromosomes and ensures its systems are ready for cell division. If all conditions are ideal, the cell is now ready to move into the first phase of mitosis. This page appears in the following eBook.

Aa Aa Aa. Walther Flemming's drawing of chromosomes. What happens during mitosis? Figure 1: During prophase, the chromosomes in a cell's nucleus condense to the point that they can be viewed using a light microscope. Prophase is the first phase of mitosis. During this phase, the chromosomes inside the cell's nucleus condense and form tight structures.

In fact, the chromosomes become so dense that they appear as curvy, dark lines when viewed under a microscope Figure 1. Because each chromosome was duplicated during S phase, it now consists of two identical copies called sister chromatids that are attached at a common center point called the centromere.

Figure 2: The mitotic spindle white begins to form outside the cell's nucleus. Important changes also take place outside of the nucleus during prophase. For more information about mitosis, check the answer to the following question on this website: What is mitosis?

In what phase of mitosis does the DNA replication occur? Jun 15, Explanation: Mitosis is the process of nuclear division of cells and is part of the cell cycle.

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