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Organization and Function within the Cell AP Big Ideas: #1—Evolution of Eukaryotic Cells #2—Cellular Organization and Structure Before there were cells… Early Cells • Evidence for heterotrophic hypothesis: – We have a single method of fermentation: glycolysis – Enzymes in glycoloysis are highly conserved; suggests the ancestral organism needed to break down materials it got from its environment: Protobionts • http://www.youtube.com/watch?v=GOTke2eJ 5K8 • Rock record shows CO2 concentration in the atomosphere from early fermentation. Once there was CO2… • Cells use the CO2 and sun’s energy to produce organic compounds (photosynthesis) • This produced O2: – First oxygen produced: iron + oxygen = iron oxides – About 500 m.y. l. free O2 existed. • Aerobic bacteria evolved to use O2 for respiration=more efficient. Once there was oxygen… • Eukaroytic cells formed… • Multicellularity evolved… • Sexual reproduction evolved… • “Explosion” of multicellular life in the last 1000 million years!(CalledPrecambrian) 3 Main Eras in Multicellular Time • Paleozoic: Diversity in the ocean (500-250 mya) • Mesozoic: Diversity on Land: Large reptiles; mammals small (250-65 mya) • Cenozoic: Age of flowering plants and mammals (65 mya – present) • Each era ended with a Mass Extinction Endosymbiosis—Describe the theory in words A theory needs evidence… • mtDNA and cpDNA • Ribosomes and protein synthesis • Size/Structure • Double membranes • Binary Fission Why is the prevailing hypothesis that photosynthesis evolved once? • Look at the principle of parsimony within the protist kingdom. Endomembrane System Exocytosis • Production and Secretion of an “exogeneous” protein – Identify and sequence the organelles involved in protein synthesis and secretion What about an “endogenous” protein? Examples • Cell cycle proteins…endogenous • Hormones…exogenous What are steriod hormones? Where are they produced? Endocytosis • What organelles are involved? • Lysosome, vacuole, cell membrane, microfilaments What types of cells do this? • Amoeba, etc. for food • Phagocytic white blood cells