biology

Organisms grow and maintain themselves (or , in the case of single celled organisms , multiply ) through the reproduction of their individual cells . the cell cycle is the recurring chain of events that involves the whole process of cell reproduction , from a stationary phase , duplication of its genetic material (mainly DNA bound up as chromosomes , to cell division (mitosis

Cell division is an essential part of normal cell life . But when mutations (genetic damage ) occur , particularly damage sustained by both oncogenes and tumor suppressor genes , the life-sustaining process of cell replication can become

a vehicle for a potentially fatal disease cancer

Up till now , some aspects of cancer development among multicellular organisms have yet to be fully understood . A thorough understanding of all the biological aspects of cancer will bring us further into the goal of removing cancer from the list of dreaded diseases

The cell cycle

The cell cycle consists of two phases : interphase and mitosis . The interphase further consists of the G1 (gap 1 , S phase (synthesis , and G2 (gap 2 ) phases . G0 , a sub-phase of G1 . Cells in G1 that are not ready to progress in the cell cycle enter G0 for extended periods of time until they are ready to proceed . G0 can vary in length from minutes to years

It is during the G1 phase that a cell increases its volume in preparation for subsequent division . during this time the cell is also receptive to signals from other cells . G0 , a sub-phase of G1 , occurs when the cell is not yet ready to proceed with the cell cycle , because of insufficient soluble growth factors in surrounding fluid , for example . G0 varies in duration from minutes to years , depending on conditions , species , and cell type . The end of this subphase is the Restriction Point , at which the remaining cell cycle will progress regardless of the presence or absence of soluble growth factors . DNA is replicated in the S phase , which comes before cell division

after which comes the G2 phase . After the S phase come the G2 phase which is a "checkpoint " phase , where a cell "checks " to see if it is ready for mitosis

After the S phase comes mitosis , at which the cell starts to divide into two daughter cells . to be able to divide the membrane of the cell 's nucleus dissolves . The chromosomes then separate into two sides of the cell so that each side gets one copy of each chromosome , after mitosis comes cytokinesis , at which the cell actually splits into two halves the cell splits , and the nuclear membrane reforms

Passage through the cell cycle in mitotic division is controlled by MPF and APC . MPF is called maturation-promoting factor for its role in developing oocytes , and the APC (also called the cyclosome , is the anaphase-promoting complex

Carcinogenesis

The maintenance of the population of cells (in multicellular organisms involves the proper balance between cell proliferation and programmed cell death . However , DNA damage (which are essentially mutations ) can disrupt normal cell cycle processes and...