biology 251 chapter 1

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ribosomes are composed of?
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Terms in this set (30)
covalent bonds consist ofelectronsprimordial soup experiment of 1953 - replicated? - had? - organic compounds? - has been modified over last 60 years and yielded?- replicated environmental conditions of prebiotic times - atmosphere - H2O, H2, CH4, NH3 - has been modified last 60 years and yielded all amino acids and simple organic moleculesMurchison Meteorite 1969 - analysis identified? - what did he find in cells?- amino acids and organic compounds - organic compounds were found in cells and can form under the appropriate forms in natureastrobiology -study of? -what do mars orbiters and rovers look for? - what type of molecules are being looked at?- origin, evolution, distribution and future of life in the universe - the mars orbiters and rovers look for chemical signatures consistent with organic molecules associated with cells - biologically relevant moleculesstromatolites - what are they? - where are they found? - how old are they? - what are they not? - banded domes of? - community of?- microbial fossils in layered sedimentary rock - west Australia - 3.8b BYA - they are fossils, not living organisms - banded domes of sedimentary rock reminiscent of modern layered microbial mats - community of physiologically integrated organismsSIMS - meaning? - analysis of? - measures the ratio of? - cells have more? - isotopic ratio is consistent with? - how old?- secondary ion mass spectometry - analysis of the oldest microfossils that documents their carbon isotope compositions - measures the ratio of 13C to 12C in microfossils - cells have more 12C - isotopic ratio is consistent with life - Australian microfossils dated to 3.77 to 4.29 BYAwhat is the best evidence that life first appeared 3.8 BYA A- presence of iron oxides B-rapid accumulation of atmospheric O2 (oxygen gas) C-fossils with bilateral symmetry D-stromatolite microfossils E-sterol droplets within quartzD - stromatolite microfossilsAtmospheric oxygen O2 - accumulation produced by? - ancient earth had very little? - the first cells were? and what do they not use - what type of organisms were present at the time? - where are the two types of alternate forms of photosynthesis?- produced by photosynthetic bacteria - very little free O2 - the first cells were anaerobes and they did not use O2 as an electron acceptor - anoxygenic photosynthetic organisms were present -oxygenic and anoxygenic photosynthesiswhat is the formula for oxygenic photosynthesis? what is the formula for anoxygenic photosynthesis?oxygenic, (carbon dioxide + water + light energy --> glucose, oxygen and water) 6CO2 + 12H2O + Light Energy --> C6H12O6 + 6H2O anoxygenic, (carbon dioxide + electron donor + light energy --> carbohydrate + water) CO2 + 2 H2A + light energy --> [CH2O] + 2A + H2O types of electron donors: H2S, H2, S0oxygenic photosynthesis 2.3 BYA - which molecules are similar? - what is photosystem 2 about? - what does h2o serve as? - what does oxygenic photosynthesis release? - this led to? - what evolutionized?- H2S and H2O - evolution of H2O splitting enzyme - h2o serves as a source of electrons -oxygenic photosynthesis releases O2 atmospheric ozone (O3) layer and blocks harmful UV radiation - led to aerobic respiration that produces 20x more ATP -the evolution of eukaryotesoxygen accumulation - photosynthetic bacteria started producing? - after O2 accumulated, what occurred after? - no iron oxides occurred before?- 2.3 BYA - iron oxidation occurred, reddish iron oxide; iron III or ferric oxide - no iron oxides before 2.3 BYAclassify each domain group A spirochetes chlamydiae cyanobacteria gram positive bacteria B crenarchaeota euryarchaeota korarchaeota C mastigophora sarcodina animals fungi plants ciliphora apicomplexa D common ancestor of all living thingsA - domain bacteria B - domain archaea C - domain eukarua D- LUCADomain - largest? - how is the tree built? - all cells have?- largest taxonomic group - from comparing DNA sequences for ribosomal RNA (rRNA) genes - all cells have ribosomes ribosomes are made up of RNA **rRNA genes mutate slowly/constant predictable rate ** closely related species have similar rRNA sequences ** distantly related species have more differencesribosomes are composed of?protein and rnaprokaryotic - what is the small subunit? eukaryotic - what is the small subunit?prokaryotic --> the small subunit 30S of the prokaryotic ribosome composed of 16S RNA eukaryotic --> the small subunit of 40S of the eukaryotic ribosome is composed of 18S RNAwhat is the Svedberg unit?(s) is a unit describing sedimentation rate in centrifuge tubeLUCA - stands for? -what is used as a model for LUCA? and why - comparison of?-last universal common ancestor - bacteria and archaea near the main trunk ** bc the tree of life is complicated by horizontal gene transfer, endosymbiosis, and fusion ** the tree gets messy - comparison of complete genomes from all three domains shows substantial transfer of geneshorizontal gene transfer -transfer of? classify the following a-physical contact between cells b-uptake of DNA from the environment c-DNA is moved by viruses d-DNA is transferred from the endosymbiont to nucleus e-two organisms become one- transfer of genes across species barrier a- conjugation b- transformation c- transduction d- endosymbiosis e- fusion of organismsclassify the following A - conjugation, transformation, transduction - transposable elements, topics for future lecture B - DNA transferred from the endosymbiont to nucleus C - two organisms become oneA- horizontal gene transfer B- endosymbiosis C- fusion of organismsexam question *** identify the type of prokaryotic rRNA (ribosomal RNA) used in the three domain tree of life16S RNA