Problem set 4key - Problem set 4 Key Chapters 12 and 13 1....

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Problem set 4 Key – Chapters 12 and 13 1. What is the consensus of the following sequences from a hypothetical regulatory region of different genes? In general why is it useful to look at a consensus sequence and in this example, which base positions do you expect to have the most functional significance? Be specific. CCAATTCATAAT CCATAACATTAT CCATATCATAAT ACATATCATCAT ACATATCATTAT CCAATTAATGAT CCATATCATNAT -63 -52 The consensus sequence is shown in bold (the numbers were added to make referring to a particular base easier- your answer need not have any numbers). The N indicates a base position (-54) at which there is no real consensus. The base positions which are identical in sequence for different genes in this hypothetical regulatory region are those that are most likely to have functional significance. For example, those at -52, - 53, -55, etc. In general, bases that are conserved have some functional significance, otherwise random mutations would result in sequence differences. 2. Please describe the three modifications that are made to eukaryotic pre-mRNA before it is mature and ready to be translated. What is the significance of each modification with regard to translation of that mature mRNA? a) The 5’ cap (7- methyl guanosine) is added soon after transcription begins. It is necessary for the initiation of translation. b) as transcription occurs the introns are spliced out and the exons are joined. This is important in generating a mature mRNA that is an open reading frame and that contains the desired amino acids. c)
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This note was uploaded on 04/27/2009 for the course BIO 340 taught by Professor Steele during the Spring '09 term at University of Arizona- Tucson.

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Problem set 4key - Problem set 4 Key Chapters 12 and 13 1....

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