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Biology Unit 4
Origin of Life
| Question | Answer |
|---|---|
| cosmologist (origin of matter) | began with a large bang. big bang. lightest elements(h,he,li) product of it. atomic nuclei became attracted to each other. hot enough=formed into stars. stardust is basic building block of everything else including life |
| red giant | late evolutionary stage of a star. 1-5 solar masses (1-5x larger than our sun). burn H& d a nuclear fusion reaction->He. lots of heat given off. energy trying to get out, gravity trying to get in.(why it looks like burning) |
| paleoenvironment | earth formed 4.6 billion years ago. thought earth was formed on its own way |
| nebular hypothesis | solar system formation from a great rotating cloud of dust |
| theory of accretion-otto schmitt | particulates coming together to form particulates (stick together) and then from dust clouds, attracking clouds, ect to planets. |
| earths atomosphere formed by outgassing | source of hear inside the earth heat up because of radioactive decay. primitive atmosphere was a reducing atmosphere of water vapour, N, CO2. small amounts of H, CO, CH4, H2S. come together to form complete molecules. |
| 3 possibilities of life | god induced.panspermia: theory by francis crick first discovered&described dna) states that life developed on earth, simply by aliens coming&population it. chemical evolution: life originated on earth&evolved on earthevolved under conditions can stimulate |
| unity of life=common chemical evolution aa-amino acid. protiens are all made from the same 20 amino acids all are left handed | a living organism is a system of chemicals with the capacity to maintain itself &catalyse its own reproduction. all living organisms has: 4 bases make up dna, atp is most common energy sourse, 3n nucleotide codon is consistently interpreteted into aa sequ |
| stage 1 of chemical evolution. | organic molecules. simple building blocks. nucleotides and amino acids were produced prior to the existence of cells |
| stage 2 chemical evolution | macromolecules. nucleotides&amino acids polymerized to form dna, rna & proteins |
| stage 3 chemical evolution | plasma membrane. polymers become enclosed in membranes |
| stage 4 chemical evolution | metabolism and chemical evolution. membrane bound polymers evolved cellular properties. |
| stage 1 organic molecules | conditions on earth may have been conducive to spontaneous formation of organic molecules. organic molecules may have been derived from outside planet. darwin said life probably started in a tidal pool. oparin&haldane nrg source such as light |
| stage 1 reducing atmosphere aa-amino acids | miller and urey. 1953. life formed in a reducing atomosphere type of climate. simulated early life atmosphere (CH4, NH3, H2O, H2). used heat & electrical sparks as nrg source. afer 1 week, 10% of carbon was converted to organic compounds including aa |
| stage 1 extra terrestrial hypthesis | organic molecules are found in space in association with meteorites& the vapor trail of comets. jason dworkn-cooled chamber, injected genes (H2O, CO2, NH3) & bombards with UV simulated interstellar pre cometary ices. WILD2 |
| stage 1 deep sea vents | wachtershauser & huber proposed that key organic molecules may have originated in deep sea vents: conditions appropriate for different molecular reactions |
| stage 2 macromolecules | three primary hypothes concerning development of organic macromolecules. |
| stage 2 RNA first most popular, favoured. | easier to envision RNA evolving into DNA than other way around. ribonucleotides display 3 functions: 1.can store info, 2.rna has capacity to self replicae bc of base pairing, 3.RNA displays enzymatic properties.most likely suspect to act as a ribozyome. |
| stage 2 protein first hypthesis | sydney fox discovered that amino acids could polymerize abiotically when exposed to dry heat. there proteniods had catalyic properties=enzymes. when submersed in water, formed microspheres=might have acted as early cell membranes |
| stage 2 protein first hypothesis polymerization of proteins and nucleic acids Wacherhauer&Huber formed peptides using FeNi sulfides as inorganic catalysts under vent like conditions | catalyzed by inorganic materials contained in clay. originally proposed by Graham Carins Smith. beleived clay could act as a catalyst for polypeptide formations. polypeptides could have facilitated rna formation. |
| Stage 3 plasma membernaes | protobion-first non living structures that evolved into living cells. coacevates: small membrane like structures make of protein that has a small skin of water on outside of them. droplets that form spontaneously from the association of charged polymers. |
| 4 characteristics of protobionts | possessed a boundary to separate inside from outside world. polymers inside contain information. polymers inside possessed enzymatic function. protobionts were cabable of self reprodcution |
| microspheres vs liposomes | m: small water filled vesivles surrouned by macromolecular boundary(work with proteins). l: vesicles surrounded by a lipid layer, clay. can catalyze formation of liposomes that grow and divide. can enclose rna |
| david deamer | maintains that plasma membranes have to come first. experimented with liposomes. was able to simulate the capture of macromolecules by plasma membranes. was able to make liposomes leaky. able to produces an enzyme carrying bubble that draw nutrients in |
| protease | breaks down proteins. able to synthesisze dna enzymatically |
| stage 4 metabolism & chemical selection | evolution of metabolism: stuart & kaufmann devised a mathematical model that helps explain metabolic systems. follows that any improvement or short cut in the metabolic pathway would be selected for,bc protocell exhibiting improvement has advantage |
Created by:
bdinney22
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