Test Three

Test Three - Test Three Sections 7.14-7.17 Protein...

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Test Three Sections 7.14-7.17 Protein synthesis Translation o Protein synthesis o mRNA is translated into protein o Key players: mRNA, tRNAs, and ribosomes REMEMBER Codons o mRNA sequence of three nucleotides o Start codon (AUG) - sequence at which translation starts AUG codes for N-formylmethionine in Prokaryotes AUG codes for Methionine in Eukaryotes o Stop codon (nonsense such as UAA, UAG, UGA - don’t have to know these examples) - sequence at which translation stops o Open reading frame - from start codon to stop codon, is the location of protein-encoding genes Genetic code o Expressed in terms of mRNA codons o Many codons can code for a single amino acid o Table 7-5 Aminoacyl transfer RNA (tRNA) o Has anticodon sequence that temporarily base pairs with codon during translation o Is attached to the amino acid corresponding to the codon o Figure 7-36 o The ribosome brings together mRNA and aminoacyl tRNAs for protein synthesis Table 7-6 know details from this table Ribosome o Goes from start codon to stop codon o Moves along the mRNA one codon at a time linking the correct amino acids together o Figure 7-38 o Figure 7-2 In prokaryotes, there is no separation of transcription and translation in the cell (they occur within the same space) In eukaryotes, transcription occurs in the nucleus The mRNA has to be exported out of the nucleus and into the cytoplasm for translation to occur o Polysome - several ribosomes can translate a single mRNA molecule simultaneously Figure 7-39 Section 11.1-11.3 Early earth, the origin of life, and microbial diversification Planet earth is at least 4 billion years old First evidence for microbial life can be found in rocks about 3.86 billion years old Stromatolites - fossilized microbial mats consisting of layers of filamentous prokaryotes and trapped sediment o Phototrophic green nonsulfur bacterium Choloflexus Early earth o Anoxic o Much hotter than the present Earth o Abiotic synthesis of first biochemical molecules Figure 11-5
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Primitive metabolism o Anaerobic o Chemolithotrophic (FeS and H2S) o Autotrophic Shift from anoxic to oxic environment o Oxygenic photosynthesis in cyanobacteria appeared ~2.8 billion years ago o Banded iron formations - layers of ferric (Fe3+) iron oxides formed by ferrous (Fe2+) iron reacting with oxygen produced by the cyanobacteria o Oxygen accumulated after all ferrous iron was oxidized o Ozone (O3) layer formed Figure 11-8 Sections 11.5-11.6 Methods for determining evolutionary relationships Phylogeny - evolutionary relationships of microorganisms Evolutionary chronometers o Measures of evolutionary change o Genes (and other macromolecules) essential for cellular life Ribosomal RNAs ATPase proteins and others o Sequence comparison of these can be used to determine the evolutionary distance between microorganisms SSU (small subunit) RNA sequencing o
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This note was uploaded on 03/30/2008 for the course BIOL 2051 taught by Professor Brininstool during the Fall '07 term at LSU.

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Test Three - Test Three Sections 7.14-7.17 Protein...

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