Mitosis
Interphase
G1 Phase
During the G1 Phase, or the Growth 1 Phase, the cell takes in nutrients in order to support its rapid growth. The cell expands and the centrioles, made of microtubules, replicate in the microtubule organizing center (MOTC). S Phase
The S Phase is the DNA replication phase. Before this phase, the cell goes through the G1/S Phase checkpoint to ensure the cell is ready for DNA replication. Next the chromosomes, in the form of chromatin, replicate along with their proteins. Identical to the parental chromosome, the individual strands of chromosomes connect in pairs in a region called the centromere. This pair of connected chromosomes is called a sister chromatid. G2 Phase
The G2 Phase, or Growth 2 Phase, occurs after the S/G2 checkpoint. It is a this checkpoint that proteins repair mistakes made during DNA replication. Once this is complete, the remaining organelles and membranes duplicate. |
M-Phase (Mitosis Phase)
Prophase (early)
After the G2/M checkpoint which monitors DNA replication, Prophase takes place. During this phase the nucleolus of the cell disintegrates while the chromosomes in the form of chromatin condense to chromatids. Asters, or pairs of centrioles begin to move to opposite poles while the formation of the mitotic spindle occurs. Prometaphase
During this phase, the nuclear envelope itself disappears. The microtubials of the spindle fibers attach to the chromosomes in a region called the kinetochore. Metaphase
After the formation of the mitotic spindle occurs, the centromeres (kinetochores) will align on the metaphase plate, or equator, of the cell. Anaphase
Once the centromeres align, they are pulled apart by the mitotic spindle. This separates the sister chromatids into single stranded chromosomes. Telophase
During Telophase, two nuclei form around the separated sets of daughter chromosomes while the nucleoli reappear inside. Once inside the nucleus, the chromosomes de-condense back to chromatin form. |
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Cytokinesis
The cytoplasm of the cell will form a cleavage furrow as the membrane of the cell furrows inward, dividing the larger cell into two identical daughter cells.