Cell Life Cycle:  Cells have two major periods

Interphase:  Cell grows and carries on metabolic processes

Cell division:  Cell replicates itself, function is to produce more cells for growth and repair processes

DNA Replication

Occurs toward the end of interphase.

DNA uncoils and each side serves as a template for duplication into mRNA.         DNA doesn’t leave the nucleus.

 Events of Cell Division

Mitosis—division of the nucleus

Results in the formation of two daughter nuclei

Cytokinesis—division of the cytoplasm 

Begins when mitosis is near completion

Results in the formation of two daughter cells

Stages of Mitosis

Prophase

First part of cell division

Nuclear envelope breaks down; DNA condenses into chromosomes (sister chromatids)

Centrioles migrate to the poles to direct assembly of mitotic spindle fibers

Metaphase

Chromosomes are aligned in the center of the cell on the metaphase plate

Anaphase

Chromosomes are pulled apart and toward the opposite ends of the cell

Telophase

Chromosomes uncoil to become chromatin and nuclear envelope forms around them

Spindles break down and disappear

Cytokinesis

Begins during late anaphase and completes during telophase.

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