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The Importance of Mitosis. The need to heal!. The need to grow!. DNA. Made of nucleotides Phosphate sugar Nitrogen base Adenine Guanine Cytosine thymine. Coiling. Uncoiled DNA called chromatin- between cell divisions Happens during cell division
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DNA • Made of nucleotides • Phosphate • sugar • Nitrogen base • Adenine • Guanine • Cytosine • thymine
Coiling • Uncoiled DNA called chromatin- between cell divisions • Happens during cell division • DNA wraps tightly around proteins called histones
Chromosomes • Chromosome- consists of two identical halves connected together by a cnetromere • Chromatid- a half of one chromosome. • Contains one complete set of information • Copies itself to make the other chromatid
How many chromosomes?? • Each human diploid cell is 2N and contains 46 total • 23 identical pairs ( 23 x 2 = 46 ) “homologous chromosomes” carry the same traits
How many chromosomes?? • Egg and sperm cells only carry one set of 23 • Each human haploid cell is “N” • Egg and sperm combine to form 2N or 46 • All other chromosomes are called autosomes • Each human or animal cell has sex chromosomes XX or XY • Define the sex of the organism
Cell Cycle • G1 = cell grows • S = DNA replication • G2= Prepare to divide • M= Mitosis INTERPHASE
2-4-8-16, etc… Quicktime video
Stages of Mitosis • Prophase • Metaphase • Anaphase • Telophase • Cytokinesis
Birth of a Brain Cell • Quicktime movie
YOUR QUIZ ON MITOSIS IS TOM. • Here’s what you need to be able to do…