CELL DIVISION Cell Cycle Chromosome Binary Fission Homologous

CELL DIVISION

Cell Cycle: Chromosome Binary Fission: Homologous Chromosome: Chromatids Centromere Centriole Mitosis Cytokinesis

VOCABULARY Cell Cycle: life cycle of a cell Chromosome: Organized structures of DNA during the cell cycle- Humans have 46 chromosomes Binary Fission: Process of cell division in which 1 cell simply splits into 2 (bacteria) Homologous Chromosome: Chromosomes of matching information (pairs of chromosomes)- Humans have 23 homologous chromosomes Chromatids: Identical copies of chromosomes Centromere: Center that holds the chromatids together Centrioles: Structure that assists in cell division Mitosis: Process of nuclear division (2 nd part of cell cycle) Cytokinesis: Process of the cytoplasm dividing (3 rd part of cell cycle)

Why do cells divide? • Reproduction • Growth • Repair How does the cell know how to divide? The DNA has the instructions for all of the cell’s activities.

CELL DIVISION PROKARYOTIC CELLS Bacteria Binary Fission make copies Cell splits in two EUKARYOTIC CELLS Animal, Plant, Protists, Fungi DNA Cell Cycle Three stage, multistep process to duplicate a cell

CELL CYCLE Process in which new eukaryotic cells are formed from old cells Life cycle of a cell

CELL CYCLE Consists of three stages 1. Interphase 2. Mitosis 3. Cytokinesis Results in cells identical to parent cells

The sequence of development and division of a cell 3 Parts 1. Interphase - Preparation 2. Mitosis – Cell division 3. Cytokinesis – Splitting How long does it take? • Adult human cell: ~24 hrs • 18 -20 hours in interphase • 2 hours in mitosis • Embryonic cells: 30 min.

1. INTERPHASE � Cells grow and copy organelles and chromosomes � In-between phase

What happens • Cell doubles in size • DNA replicates • Organelles double in number

2. MITOSIS Process of nuclear division in cells Occurs in eukaryotic cells Four phases (PMAT) Prophase Metaphase Anaphase Telophase

PROPHASE (PAIR) Nuclear membrane disappears Chromatids form and pair up Chromosomes are a pair of chromatids held together at the center with a centromere

What happens • DNA forms chromosomes • Spindle forms • Centrioles move toward opposite poles • Nuclear membrane begins to disappear

METAPHASE (MIDDLE) Chromosomes the cell line up in the middle of

What happens • Nucleus has disappeared completely • Chromosomes line up in the middle of the cell “equator”

ANAPHASE (APART) Chromatids pull apart

What happens • Centromeres divide • Chromatids separate and move to opposite poles

TELOPHASE (TWO) Form two nuclei Nuclear membrane reforms

What happens • Nuclear membrane forms around each group of chromosomes • Chromosomes unwind • Cytokinesis begins

3. CYTOKINESIS Cytoplasm cells In divides and forms two new plants… Cell plate forms to split into two Cell plate becomes the new membrane/wall In Animals… Pinch apart to make two cells

What happens • Cytoplasm divides • One cell becomes 2 cells

MITOSIS SONG <iframe title="You. Tube video player" class="youtube-player" type="text/html" width="480" height="390" src="http: //www. youtube. com/embed/1 FYF DFDrym. Q" frameborder="0" allow. Full. Screen></iframe>

MITOSIS CLIPS http: //www. cellsalive. com/mitosis. htm http: //www. youtube. com/watch? v=VGV 3 fv-u. ZYI http: //www. youtube. com/watch? v=m 73 i 1 Zk 8 EA 0 http: //www. cellsalive. com/meiosis. htm