Cells and cell components Elements of the Cell Theory Schleiden and Schwann 1839 all organisms are composed of one or more cells cells are alive the basic living functional organizational units of all organisms all cells come from other cells Two main types of cell Prokaryotic no nucleus simple cells Eukaryotic with nucleus complex cells Other Important Differences Prokaryotes single celled no nucleus small many anaerobic no oxygen Eukaryotes multi celled do have a nucleus big mostly aerobic oxygen present Prokaryotes no compartments Eukaryotes compartmentalized Eukaryotic cells have internal membranes and compartments to help with a sub division of labor 1 Homeostastis maintenance of a constant internal environment 2 Organisms can lose and replace individual cells cells can live and die independent of organism 3 Cell specialization different cells perform different tasks Organelles Nucleus Where DNA resides DNA always stays in nucleus protein synthesis occurs outside nucleus Cytoplasm jelly substance that all the organelles float in water and protein Endoplasmic Reticulum ER rough ER is site of protein synthesis is rough because of presence of ribosomes smooth ER is site of lipid synthesis lumen where proteins take on tertiary structure Ribosome composed of RNA and protein site of protein synthesis where protein is made are attached to ER Golgi Complex or Golgi Apparatus proteins are further processed modified like the post office of the cell Lysosome breaks down old organelles digestion of food Garbage man of the cell Cytoskeleton internal cell structure a series of protein strands Anchor structure gives cells their shape and guides particles around Mitochondria cell powerhouse this is the organelle where glucose is broken down and ATP is produced site of ATP synthesis requires oxygen Plant cell has chloroplast site of photosynthesis Cell wall mostly cellulose Central vacuole 90 water Chloroplast The Endosymbiotic Theory symbiosis living together sometimes lives in mutual beneficial endosymbiosis a mutually beneficial interdependence between two species one of which resides permanently inside the other s body long term symbiosis can lead to new organs tissues behaviors The mitochondria and chloroplasts are now recognized to be descendents of ancient bacteria now incorporated into cells Evidence each divide independently of host cell under their own genetic control have DNA similar to bacterial DNA i e occurs as small loops simple DNA have small unique ribosomes similar to bacteria protein synthesis is inhibited by antibiotics specific for bacteria
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