Cell Cycle and Cell Division

BIG PICTURE

Mitosis 2n 2n 2n One (Diploid) Cell becomes Two (Diploid) Cells Example : Cats Somatic Cells have 38 (2n) chromosomes Sex cells have 19 (n) chromosomes

Chromosomes Contain the genetic information How this information is transmitted from one cell to another 2 sister chromatids DNA Replication Centromere Arm Genes/DNA Chromosome (unduplicated) Chromosome (duplicated)

A Chromosome

Number of Chromosomes Types of Chromosomes (Humans) Body (Autosomes) – 44 chromosomes (22 pairs) Sex – 2 chromosomes (1 pair) (females XX, males XY) Total Number of Chromosomes = 46

Cell Cycle Two main phases: Interphase 3 stages G1 – rapid growth S – DNA replication G2 – prepare for mitosis 2. Mitosis (M) = cell division 4 stages Prophase Metaphase Anaphase Telophase

Mitosis Interphase Cytokinesis Telophase Prophase Anaphase Metaphase

Interphase DNA replication All chromosome have two sister chromatids

Prophase Chromosome formation DNA condenses Nuclear membrane dissolves Centrioles move to opposite poles of cell

Metaphase Centromere of chromosomes joins to spindle fiber Chromosomes line up in the middle of the cell

Anaphase Centromere doubles Chromatids separate and are pulled to opposite poles by the spindle fibers

Telophase Cytokinesis – separation of cytoplasm; Nuclear membrane reappears in the two daughter cells Cytokinesis – separation of cytoplasm; final stage of cell division

Mitosis under the microscope PROPHASE TELOPHASE METAPHASE ANAPHASE

Mitosis Lab –Root Tip Telophase Prophase Anaphase Metaphase Interphase

Vocabulary The Cell Cycle Chromosomes Interphase Mitosis Prophase Metaphase Anaphase Telophase Cytokinesis

Homework Page 44 Questions #1 - 7

Mitosis On the Table Using pipe cleaners and your text, recreate the stages of mitosis on your desk with a partner 1 partner tries each phase, and the other partner checks to make sure it’s done correctly Raise your hand for teacher to check Then switch roles