Bell Ringer: No paper needed Why do cells divide?

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Cell Division: It’s Mitosis…..not Your Tosis….

 Cell Division: (Mitosis) the process by which a cell divides into two new daughter cells.  Why do cells divide?  They divide before they become too large!  Nucleus has a hard time managing a cell that is too large.

Cancer: Uncontrolled Cell Growth  Cells lose control over their cell cycle and they start dividing uncontrollably and end up with a huge number of cells.

Chromosomes  Contains Genetic Material (DNA).  Each living thing has a specific number  Fruit Flies have 8  Carrots have 18  Humans have 46

Chromatin  Granular material visible within the nucleus  During cell division, Chromatin condenses to formed Chromosomes Chromatin Chromosome

Chromosomes and Cell Division  Before cell division, each chromosome is replicated or copied.  Each chromosome is made up of 2 identical sister chromatids attached at an area called the centromere.

Cell Cycle Definition:A series of events that cells go through as they grow and divide. M phase G 2 phase S phase G 1 phase M phase (Mitosis)

Events of the Cell Cycle  Interphase: Longest phase of the cell’s life. Divided into the G1, S1, and G2 phases  Cell Division: (M phase: Mitosis) Is relatively fast M phase (Mitosis) G2 phase S phase G1 phase

2 Stages of Cell Division (the M phase)  Mitosis: Cell nucleus divides  Cytokinesis: Cytoplasm divides M phase (Mitosis)

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

Interphase  Longest phase of the cell’s life  G1: Phase when cells do most of their growing.  S1: DNA is replicated  G2: Organelles are produced in order to prepare for Mitosis

Cell Membrane (Membrane)

Interphase Animal Cell Plant Cell Photographs from:

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

Prophase 1. Chromatin condenses into Chromosomes. 2. Centrioles separate and take position on opposite sides of the nucleus 3. Spindle fibers begin to form between the centrioles.

Prophase Animal Cell Plant Cell Photographs from:

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

Metaphase  Chromosomes line up across the center of the cell.

Fibers

Metaphase Animal Cell Plant Cell Photographs from:

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

Anaphase  The sister chromatids separate into individual chromosomes and are pulled apart by the Spindle Fibers!

Anaphase Animal Cell Plant Cell Photographs from:

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

Telophase  Chromosomes gather at opposite sides of the cell.  Chromosome break apart into Chromatin

Centrioles Chromatin Interphase Nuclear envelope Cytokinesis Nuclear envelope reforming Telophase Anaphase Individual chromosomes Metaphase Centriole Spindle Centriole Chromosomes (paired chromatids) Prophase Centromere Spindle forming Section 10-2

Cytokinesis  The cytoplasm pinches in half (organelles).  Each new daughter cell has an identical set of duplicate chromosomes.  Example: 4 Chromosomes 4 Chromosomes

Twilight Mitosis

Cytokinesis End of Cell Division

Telophase & Cytokinesis Animal Cell Plant Cell Photographs from:

Animal Mitosis -- Review Interphase Prophase Metaphase Anaphase Telophase Cytokinesis

Plant Mitosis -- Review Interphase Prophase Metaphase Anaphase Telophase Cytokinesis

Bell Ringer : Identify the following stages of the Cell Cycle Determine the proper order 1 st – 6th Metaphase Interphase Cytokinesis Telophase Prophase Anaphase 1st 4th 3rd 5th 6th 2nd