8-28-09_origin_life_eukaryotesA

8-28-09_origin_life_eukaryotesA - What were the original...

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What were the original lifeforms and how did eukaryotic cells develop? “The mystery of the history” aka The answer is 42
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The first quiz will become available on Blackboard today In Blackboard, click on Assessments in left column, then on Bio 230 Fall 2009 Quiz 1 Multiple choice questions, 30 minutes Available beginning noon today. Needs to be completed by noon on Wednesday, 9/2/09. Includes material through the first three lectures.
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General classes of cells Bacteria -Prokaryotic Plant- Eukaryotic Animal- Eukaryotic Virus? NOT a cell
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Why are viruses not cells? 1) Genetic program for limited operations only. No intrinsic means to use it 2) Reproduction only through interaction with host 3) Limited responses to stimuli 4) Limited self-regulation 5) No energy acquisition or utilization except through host 6) However, viruses can evolve their genetic program (through mutation) Whether or not viruses are considered alive is not a settled question. Paper available in “Articles of Interest – viruses_alive.pdf” in Blackboard.
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What shared traits exist in prokaryotes and eukaryotes? Sensing environment Self-regulation Self-reproduction Mutate and evolve through natural selection
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What do eukaryotes have that prokaryotes don’t?
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So where did prokaryotes and eukaryotes come from? Why is the origin of life important now? The ultimate origin of life on Earth is generally fascinating. Astrobiology: there may be many Earths in different stages of development Synthetic biology: can we create or re-create early lifeforms or other ones?
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Evolutionary history of prokaryotes and eukaryotes Photosynthetic mechanisms became refined. Cyanobacteria possess photosynthetic mechanisms that are very similar to green plants
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Prokaryotic cells came first, about 3.5 billion years ago (within 500 million years or so) The above point can be verified indirectly from the fossil record – prokaryotic cells seem to be present in rocks that are ~3.5 billion years old; 1 – 2 billion years before any evidence is seen of eukaryotes Gave rise to eukaryotic cells - the 2 types of cells are extremely likely to be related to one another because they share many complex traits Very similar genetic codes, enzymes, metabolic pathways & plasma membranes strongly implying common evolutionary history A question of major scientific interest is that there are no known clear intermediates between prokaryotes and eukaryotes, so how did eukaryotes arise?
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Carbon date rock
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8-28-09_origin_life_eukaryotesA - What were the original...

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