Lecture15.pdf - Lecture 15 The Origin of Life on Earth Last...

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Lecture 15: The Origin of Life on Earth
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Last time Deoxyribonucleic Acid Ribonucleic Acid RNA Determines a cell’s function and manufactures proteins & enzymes. DNA Stores information to copy itself to make proteins and RNA. Proteins Molecules involved in a range of cell functions: movement, structural support, defense against germs, catalysts, transporters that move molecules from cell to cell, etc.
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https://www.youtube.com/watch?v=VYQQD0KNOis
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Hadean: 3.85 – 4.57 Gyr ago. Before life. Archean: 2.5 – 3.85 Gyr ago. First life. Proterozoic: 540 Myr – 2.5 Gyr ago. First multi-celled life. Phanerozoic: < 540 Myr ago. First animal life. Four eons - major divisions of geological time.
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Prokaryotes = single-celled organism that lacks a membrane-bound nucleus, mitochondria, or any other membrane-bound organelles. Eukaryotes = any organism with cells that contain a nucleus. Can be multicellular or single cellular (e.g., animals are eukaryotes). Two types of life
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3 domains of life
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Derived via RNA data. Some caveats: - Exact relationships of the three domains & root of the tree are still being debated. - Tree may not be the best representation of the genetic relationships of all organisms. - Some genetic evidence suggests that eukaryotes evolved from the union of some bacteria and archaea (one becoming an organelle and the other the main cell). https://en.wikipedia.org/wiki/Phylogenetic_tree
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Tree of life: approximate dates
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A phylogenetic tree of life, showing the relationship between species whose genomes had been sequenced as of 2006. The very center represents the last universal ancestor of all life on earth. homo sapiens pink represents eukaryota blue represents bacteria green represents archaea
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Lipids = molecules, make cell membranes among many other functions. Metabolism = sum of chemical reactions that provide energy for life
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Lipids = molecules, make cell membranes among many other functions. Metabolism = sum of chemical reactions that provide energy for life Eukarya - in some ways a mix of bacteria and archaea properties
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Chloroplasts absorb sunlight and use it in conjunction with water and carbon dioxide gas to produce food for the plant.
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