Adult human contains an estimated 100 trillion cells and yet We start life as a single cell to grow develop and repair tissue damage. We rely on cell division in Eukaryotic cells [this] process is accomplished by a series of well orchestrated steps called mitosis Every day our bodies must produce millions of skin cells to replace those loss through normal activity Each of these cells must have a complete complement of the genetic material Prior to cell division where the cell divides into two identical cells the DNa needs to be replicated So that each daughter cell receives an exact copy Following DNa replication the chromosomes condense in the nucleus of the cell Dna condenses by wrapping around cores of histone proteins forming nucleosomes This beads on a string structure is called Chromatin as a cell prepares to divide Chromatin coils up further Shortening and condensing the chromosome the replicated chromosomes are called sister [chromatids] The replication of DnA and the formation of sister chromatids is one part of the entire cell cycle To prepare for cell division [the] cell goes through interphase which can be divided into 3 distinct phases During G1 or Gap one phase all the organelles and cytoplasmic components including the centrioles in animal cells replicate Then during s or synthesis phase the DNa replicates Finally during G2 or gap to phase all the enzymes needed to aid in the process of cell division are produced most eukaryotic cells spend a great deal of time [in] interphase and a very short period of time actually dividing a process called mitosis The cell is now ready to go through mitosis Which consists of prophase metaphase anaphase? and telophase During prophase the chromosomes condense and become visible appearing as two sister chromatids held together at the centromere The Cytoskeleton disassembles as the spindle begins to form in animal cells centrioles play an important role in the distribution of the chromosomes in the dividing cell the centrioles migrate to opposite poles Establishing a bridge of microtubules called the spindle apparatus and the nuclear envelope breaks down Towards the end of prophase Chromosomes attached by proteins in their centromeres called kinetochores to microtubules from each pole Moving the chromosomes toward the equator of the cell During metaphase [all] chromosomes are aligned at the equator of the cell called the metaphase plate Anaphase begins with the degradation of proteins that hold sister chromatids together freeing individual chromosomes the free chromosomes are then pulled by their kinetic cores to opposite poles at Telophase a cleavage furrow forms in the center of the cell This indentation is made from a constricting belt of actin filaments surrounding the inside of the cell’s circumference chromosomes cluster at opposite poles and begin D condensing as the nuclear envelope Reforms around them the spindle apparatus Disassembles as the Microtubules are broken down into tubulin monomers that can be used to form the cytoskeleton of the daughter cells in animal cells Cytokinesis completes cell division by extending the cleavage furrow to completely separate [the] newly formed daughter cells since plant cell Walls cannot be constricted by actin Fibers vesicles form an expanding Membrane partition called the cell plate like animal cells plant cells use Cytokinesis to finish the division of the contents of the cytoplasm between the two identical daughter cells During the cell cycle certain checkpoints are encountered to make sure the process is occurring accurately and if it is not the cell cycle will stop at the checkpoint and correct or Possibly inhibit that cell from dividing the first checkpoint [is] the G1/s checkpoint And is considered the primary point at which the cell cycle continues or stops External signals and growth factors can influence the cell cycle and affect the progress at or before this critical checkpoint The G2m Checkpoint allows cells that have successfully completed all three phases of interphase to begin mitosis The last Checkpoint is the spindle checkpoint? Ensuring that all chromosomes have attached to the spindle in preparation for anaphase Growth Factors the size of the cell and the nutritional state of the cell are all contributing factors in cell cycle regulation ensuring that only certain cells divide at appropriate times Once all the checkpoints in interphase are cleared mitosis can occur from interphase – Cytokinesis the entire process of cell division Can take on average 10 to 20 hours [in] a typical plant or animal cell? Depending on the nature and use of the cell the process can happen at different frequencies as well In humans our skin cells have a high turnover rate due to wear [and] tear and go through mitosis very frequently Whereas other cells such as adult neurons and muscle cells rarely divide the accuracy [of] Mitosis as well as the consistency of the checkpoints during interphase ensure that most cells in a eukaryotic Organism can Produce identical copies of themselves This process allows for growth and repair to prolong overall Physiology as well as life itself