CELL DIVISION 2016 Paul Billiet ODWS Mesenchymal precursor
CELL DIVISION © 2016 Paul Billiet ODWS Mesenchymal precursor cells http: //www. mesoblast. com/
Cell division is a fundamental process n n n All cells come from pre-existing cells It is necessary to replace worn out cells in multicellular organisms It is required for growth in multicellular organisms q q n An increase in size will require an increase in surface area to volume ration Cell division subdivides the cytoplasm into small units (cells) surrounded by plasma membranes It is necessary for production of differentiated cells in multicellular organisms © 2016 Paul Billiet ODWS
Cell division and reproduction n It is necessary for reproduction in unicellular or multicellular organisms microbus http: //www. microscope-microscope. org © 2016 Paul Billiet ODWS
Prokaryotes n n n Prokaryotes have no nucleus They have a single circular chromosome Prokaryotes simply divide their cells in two by binary fission © 2016 Paul Billiet ODWS http: //instruct 1. cit. cornell. edu/
Eukaryotes n n Eukaryotes must divide their nucleus (and other organelles such as mitochondria) in preparation for cell division (mitosis or meiosis) Before the nucleus divides the genetic material replicates (duplicates) © 2016 Paul Billiet ODWS
Mitosis (From the Greek mitos a thread) n n Mitotic division results in genetically identical eukaryotic cells (a clone) Mitosis is the basis of asexual reproduction © 2016 Paul Billiet ODWS http: //science. tjc. edu/
Meiosis n n Meiosis results in a halving of the chromosome number in preparation for fertilisation Meiosis shuffles genes in new combinations Meiosis results in genetically different cells Meiosis and fertilisation are the basis of sexual reproduction © 2016 Paul Billiet ODWS
COMPARING MITOSIS AND MEIOSIS © 2016 Paul Billiet ODWS
COMPARING MITOSIS AND MEIOSIS © 2016 Paul Billiet ODWS
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