13020512
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Karteikarten von J yadonknow, aktualisiert more than 1 year ago
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Erstellt von J yadonknow
vor fast 7 Jahre
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| Frage | Antworten |
| LUCA components (6) | Cells Membranes Basic metabolism Nucleic Acids Genetic Code ATP |
| Why RNA world hypothesis feasible? | as RNA can perform both catalysis and replication |
| Why not DNA? | No DNA-catalysed protein activity Bacteria + Archaea have dif. rep. EZ, so DNA replication evolved after these groups split, must have something occurred before DNA. |
| What is the correlation btw. 1st base of codon and Biosynth pathway of the AA they encode? CAU | C = AA from a-ketoglutarate A = AA from oxaloacetate U = AA from pyruvate |
| What is the correlation btw. 2nd base of codon and nature of AA they encode? | A = hydrophilic AA U = hydrophobic AA |
| How did these single AA bind? | AA transfer to a larger strand which is more stable so E favourable. |
| What proof exists that implies this process could've occurred in Early Earth? | RNA Pol' occurs spontaneously in vents |
| How is RNA pol' generated in vents? | Convection and thermal currents silt-up vents w/ molecules inc. RNA Thermal gradients act like PCR |
| What does RNA in conc. do? | Get faster at replicating so RNA strand gets longer |
| Evolution of riboproteins | RNA strand becomes structural AND catalytic Structural elements eventually become protein Riboproteins evolve. |
| Why is it possible that DNA evolved from RNA? | Can derive deoxyribose from ribose Thymine from Uracil |
| Met processes are possible in vents due to these conditions: (5) | Acid-Alkali (proton) gradients Conc. Space heat H, H+ and redox precursors Storable energy |
| AA and proteins can form because: | Vent chambers contain precursor of AAs Energy and redox ' support AA synthesis |
| AA can react w/ and be catalysed by DNA because: | Vent chambers contain precursor of AAs Energy and redox ' support AA synthesis |
| RNA can be complex and converted into DNA, which is: | A stable heritable molecule for replicating processes. |
| How are carbon compounds synthesised from scratch? | By running TCA cycle in reverse |
| Where does this process occur? | In Archaea in Deep Sea Vents |
| What conditions must be met? | Given enough [compound] and a supply of ATP, cycle will run on its own. |
| What is the Martin-Russell Theory? | Acetyl thioesters e.g. AcCoA -> pyruvic acid -> acetyl phosphate |
| How did they do this? | By producing an ETC to harness internal proton gradient |
| Why is ATP an improvement of this? | Much better at harnessing the redox ' of Alkali vents |
| What did IM proteins allow? | Lose of dependency on having an external alkaline environment |
| Why are mineral cells suitable wombs for the creation of protocells? (6) | Concentration "Stable" environment Redox pt. Catalysts (Fe-S) Concentration of nucleic acids A sub-structure for chemical reactants |
| How are early membranes thought to have arisen? | proteinaceous membrane from a froth of Fe-S bubbles around alkali vents Could have been internal linings that then developed into external coverings |
| What is therefore required of free-living status? | Ability to generate chemical gradient + store energy Membranes to contain it all. |
| How do you derive this chemical gradient and store of energy? | ETC and ATP. |
| Why is this thought to have arisen late within development? | dif. in membrane structure <-> bacteria / archaea suggest this happened quite late. |
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