Cell Growth and Reproduction Ch. 8.2 Mitosis & Cytokinesis Cell Growth and Reproduction Ch. 8.2

Why do cells divide by Mitosis? Growth &Repair Reproduction of single celled organisms under? conditions constant environment Amobea Reproducing

Cells dividing by Mitosis……. Skin Identical to original cell Same chromosome # Identical chromosome makeup

Cell Cycle “G” or Growth 1 phase “S” or DNA Synthesis 24 hours “M” or Mitosis phase / Growth 2

Where is DNA located? 1. Nucleus 2. Chromosomes DNA I

Duplicated Chromosome (Late Interphase): X Sister Chromatids Centromere

Spindle & spindle fibers: Pull apart the sister chromatids

Cytokinesis:cell’s cytoplasm divides & splits apart

Stages of Mitotic Cell Division Prophase Metaphase Anaphase Telophase “1st” “middle” “apart” “far” or separate

Interphase “Intermission” Normal metabolic activities Major state DNA= chromatin

Late Interphase Prepares for mitosis DNA doubles= Sister chromatids Centrioles double in animals X X X X X X

Prophase Nuclear membrane disappears Doubled DNA = condensed “chromosomes” Spindle fibers Prophase

Metaphase Chromosomes line up mid- cell Facing inward

Anaphase Chromosomes move to opposite poles at Centrioles in animals Spindle apparatus in plants

Telophase Cells divide Cell plate or membranes form Nucleus reappears

Returns to Interphase “Intermission” Normal metabolic activities Major state DNA=chromatin

Plant versus Animal Mitosis Cell wall from cell plate in telophase Sindles Animal: No cell wall membrane cytokinesis Centrioles

Animal Telophase Interphase

Plant Anaphase Interphase

Cancerous cells……... 1.Divide too many times 2.Divide into more than two cells! Masses of cells = “tumors” benign malignant