CELL GROWTH & REPRODUCTION Chapter 8, Section 2 pg. 201

Cell Size pg  Small cells are more efficient (work better)  Easier to bring nutrients in and get waste out  Small cells have a greater Surface Area-to- Volume Ratio so that exchange of materials across the plasma membrane is more efficient

Cell Reproduction pg. 203  Chromatin = uncondensed DNA, prior to cell division.  Chromosomes = condensed DNA, form when cell is ready to divide  Made up of 2 halves held together in the center by the centromere pg. 205

Cell Cycle (Interphase & Mitosis) pgs  Cell Cycle = sequence of growth & division of a cell, 2 parts  1. Interphase  2. Cell Division  Mitosis  Cytokinesis  1. Interphase = growth period, majority of a cell’s life – 3 parts  Cells grow (G1)  Chromosomes duplicate (S)  Prep for division (G2)

 2. Mitosis = period of division, 2 daughter cells get formed, each w/ a complete set of chromosomes  Divided into 4 Phases

Phases of Mitosis pg. 207  1. Prophase  Chromatin coils into chromosomes  Sister Chromatids = two halves of the chromosome, chromatids are genetically identical  Nuclear Envelope & Nucleolus break down  Centrioles start sending out Spindle Fibers

 2. Metaphase  Chromosomes line up in the center of the cell  Spindle Fibers attach the chromatids

 3. Anaphase  Separation of Sister Chromatids

 4. Telophase  Chromatids pulled to opposite ends of the cell  Nuclear Envelope & Nucleolus re-form

 Cytokinesis pg. 209= division of the cytoplasm  Cleavage Furrow in animals  Cell Plate in plants

 cellsalive.com/cell_cycle.htm

Cancer (Ch. 8, Sec. 3)  Results from uncontrolled cell division, over 200 different types  Cell division is controlled by enzymes. What controls enzyme production?  If the DNA of a cell is damaged/altered, regulation of cell division can be affected  What environmental factors can damage cells?  Ultraviolet rays, exposure to toxic materials, tobacco, obesity  Other factors include genetics, lack of exercise, obesity, unhealthy diet

Practice  Lung cancer is the leading cause of death by cancer for males and females. Explain how this statistic can be easily reduced.