What are the major stages of the cell cycle and what major events take place during each stage?
The cell cycle is sometimes referred to as the life story of the cell and involves the stages that is passes through during the division process. This process is extremely important from the standpoint of genetics, because the cycle results in genetic instructions for all characteristics being passed down from a parent cell to a daughter cell. The cycle occurs in two majors phases known as interphase and M-phase.
Interphase is the period of time between cell divisions, and involves cell growth, development, and preparation for division. DNA, RNA, and proteins are synthesized during interphase and chromosomes are duplicated to form what are called sister chromatids.
M-phase is the next component of the cell cycle and involves six sub-stages: prophase, prometaphase, metaphase, anaphase, telophase, and cytokenesis. During prophase, chromosomes condense and the mitotic spindle, a combination of microtubules that propel the chromosomes during mitosis, forms. Prometaphase involves the disintegration of the nuclear membrane, and spindle microtubules make attach to chromosomes to begin movement towards the center of the cell. During metaphase, the chromosomes line up in the middle of the cell before being separated. During anaphase, sister chromatids separate and begin to move towards opposite poles of the cell. During telophase, the last phase of mitosis, the chromosomes arrive at the poles, the nuclear membrane reforms, and the chromosomes are able to relax. The final stage of M-phase is called cytokenesis. This involves the division of the cytoplasm to form two separate cells.