Lab 4 Cell Cycle and Mitosis THE CELL

Lab # 4 Cell Cycle and Mitosis

THE CELL CYCLE I N T E R P H A S E 1 - C E L L G R O W I N G 2 - DNA REPLICATING Gap 1 or G 1 I N T E R P H A S E 3 - CELL PREPARING TO DIVIDE S phase MITOTIC PHASE 4 - C E L L D I V I D I N G MITOSIS Gap 2 or G 2 CYTOKINESIS M phase

Cy to k ine sis pha Telo Anaphase e as ph o Pr aph Met se Copyright © The Mc. Graw-Hill Companies, Inc. Permission required for reproduction or display. G 2 Second gap phase Growth and preparation for mitosis G 1 First gap phase Growth and normal metabolic roles S Synthesis phase DNA replication Interphase

Sister chromatids Supercoiled chromatin Centromere Cell prepared Visible for division chromosome Kinetochore After DNA replication Chromosome Nondividing cell Chromatin DNA double helix Before DNA replication Histones Nucleosome Chromosome

One chromosome with one chromatid. Before DNA replication. Non-dividing cell DNA replication One chromosome with two sister chromatids. After DNA replication. Mother cell ready to divide MITOSIS Daughter Cell Two new chromosomes It is the process by which the duplicated chromosomes are separated into two identical parts before the cytokinesis. Daughter Cell

Overview of the Cell Cycle Cytokinesis It is the division of the cytoplasm to form two new cells DNA replication MITOSIS Mitosis is the process by which the duplicated chromosomes are separated into two identical parts before the cytokinesis.

MITOSIS is the process by which the duplicated chromosomes are separated into two identical parts before the cytokinesis. MITOSIS is one smooth continuous process, but it is described in stages. INTERPHASE ANAPHASE PROPHASE TELOPHASE METAPHASE

INTERPHASE PROPHASE 1 - Chromosomes condense and nuclear envelope disappears. 2 - Centrioles migrate to opposite poles of the cells. 3 - Spindle fibers grow from the centrioles and the mitotic spindle begins to form. 4 - The nucleoli desappear.

METAPHASE 1 - The chromosomes align in the equator of the cell (metaphase plate). ANAPHASE 1 - The centromere of each chromosome splits and the chromatids are separated. 2 - Each chromatid is pulled apart toward opposite poles of the cells and each one becomes a daughter chromosome. TELOPHASE 1 - The nuclear membrane re -forms. 2 - The chromosomes gradually uncoil. 3 - The nucleoli reappear.

1 Prophase Chromosomes condense and nuclear envelope 1 breaks down. Spindle fibers grow from centrioles. Centrioles migrate to opposite poles of cell. Aster 2 2 Metaphase Chromosomes lie along midline of cell. Some spindle fibers attach to kinetochores. Fibers of aster attach to plasma membrane. 3 Spindle fibers Centriole 3 Anaphase Centromeres divide in two. Spindle fibers pull sister chromatids to opposite poles of cell. Each pole (future daughter cell) now has an identical set of genes. Chromatids Kinetochore © Ed Reschke

Copyright © The Mc. Graw-Hill Companies, Inc. Permission required for reproduction or display. 4 Telophase 4 Chromosomes gather at each pole of cell. Chromatin decondenses. New nuclear envelope appears at each pole. New nucleoli appear in each nucleus Mitotic spindle vanishes Cleavage furrow Nuclear envelope re-forming Cytokinesis Chromatin Nucleolus © Ed Reschke Daughter cells in interphase

Prophase Anaphase Telophase Metaphase Cytokinesis

Early Late Metaphase

Anaphase Telophase Early Late