生物化学与生理学：开放获取

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Cell Biology Biochemicals for Cell Growth

Mark Storey Smith

Cell cycle is a highly ordered process that results in the duplication and transmission of genetic information from one generation to the next.

The cell cycle is divided into various phases

G1 2. S phase 3. G2 4. M phase.

Interrupting every two mitotic phases, an interphase exists comprising of G1, S and G2 phases. Both extracellular and intracellular signals are responsible for governing the cells to progress through different stages of cell cycle. The G1 phase is associated with the cell growth. It is the preparatory phase for DNA synthesis. The S phase is devoted to DNA synthesis while G2 is another growth phase. The M phase comprises of the following stages sequentially:

1. Prophase: The replicated chromosomes condense and the mitotic spindle begins to assemble outside the nucleus. 2. Prometaphase: The membrane surrounding the nucleus (nuclear envelope) breaks down and allows the mitotic spindle to contact the chromosomes. 3. Metaphase: All the chromosomes are gathered at the center of the cell i.e. equatorial plate 4. Anaphase: The chromosomes are split apart and pulled towards opposite sides of the cell. 5. Telophase: The nuclear envelope reassembles around the two new sets of separated chromosomes to form two nuclei. 6. Cytokinesis: The last phase in which the other components of the cell, membranes, cytoskeleton, organelles, and soluble proteins, are distributed to the two daughter cells through a process called cytokinesis