Endosymbiosis & Specialized Cells 9 Biology

Endosymbiosis Endosymbiotic Theory: Evidence: Mitochondria and chloroplasts were thought to have been free- living prokaryotic cells These structures were taken in by a eukaryotic cell, became useful to the cell metabolism and were retained as organelles Evidence: Both mitochondria and chloroplasts have: 70s ribosomes Own DNA Ability to reproduce independently from the cell Double membrane on outside Same size as prokaryotic cells

Specialized Cells: Animal cell examples: Plant Cell Examples: Blood cells: anucleate, more room for hemoglobin thus more room for O2 molecules Muscle cells: multinucleate, more mitochondria to produce more ATP needed for movement, have contractile fibers Epithelial cells: skin cells modified to be a waterproof barrier for organisms Plant Cell Examples: Root cells: modified for absorbtion of water Stem cells: modified to include vascular tissue to distribute water and glucose Leaf cells: Extra chloroplasts for photosynthesis and storage areas for gas exchange with environment

Specialized Cell Examples