Cell Division

Cell Division Mitosis – Occurs in BODY cells only!! Every cell must first copy its genetic information before cell division begins. ***Each daughter cell then gets an exact, complete copy of that information from the parent cell***

The Cell Cycle Series of events that cells go through as they grow and divide The “parent” cell grows, divides, and forms two “daughter” cells that each begin the cycle again G1 phase S phase G2 phase

The Cell Cycle Cell Cycle includes M phase (Mitosis) Interphase is divided into is divided into G1 phase S phase Prophase G2 phase Metaphase Telophase Anaphase

Events of the Cell Cycle Interphase – time when cell isn’t dividing – can be long. Made up of 3 phases: G1 – cells grow and create new proteins and organelles S – chromosomes replicated and make DNA G2 – shortest of the three phases and organelles required for cell division made (Interphase is NOT part of Mitosis!)

Interphase

M-Phase: Mitosis Takes place quicker than Interphase, Occurs in somatic (body) cells only. Mitosis has four phases: Prophase Metaphase Anaphase Telophase

Prophase 1st and longest phase – chromosomes become visible. The centrioles separate and send spindles (tube-like structures) out to attach to chromosomes. Nuclear membrane breaks down.

Prophase

Metaphase 2nd and pretty short phase – chromosomes line up at center of cell

Metaphase

Anaphase 3rd phase – chromosomes separate and become individual chromosomes. They move to the poles of the spindle.

Anaphase

Telophase 4th phase – chromosomes begin to disperse into a tangle of dense material. Nuclear membrane re-forms around chromosomes and spindle breaks down.

Telophase

Cytokinesis At the end of Telophase, two nuclei are within cytoplasm of one cell. Cytokinesis divides the cytoplasm and occurs at the same time as Telophase Cytoplasm pinched in two to create ***two daughter cells genetically identical to one another***

Mitosis and Cytokinesis Spindle forming Centrioles Nuclear envelope Chromatin Centromere Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming

Mitosis and Cytokinesis Spindle forming Centrioles Nuclear envelope Chromatin Centromere Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming

Mitosis and Cytokinesis Spindle forming Centrioles Nuclear envelope Chromatin Centromere Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming

Mitosis and Cytokinesis Spindle forming Centrioles Nuclear envelope Chromatin Centromere Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming

Mitosis and Cytokinesis Spindle forming Centrioles Nuclear envelope Chromatin Centromere Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming

Mitosis and Cytokinesis Spindle forming Centrioles Nuclear envelope Chromatin Centromere Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming

Summary of Mitosis Occurs in body cells Makes 2 genetically identical cells with the same amount of chromosomes as parent cells PMAT – four stages of mitosis