L> exam 3 Answer crucial Chemistry 332 - Winter 1997Exam 3: Chapters 15, 16 - price Key1. (15 points) Write finish structures for the following:a) the dipeptide ValGln as it would show up at pH 7b) ATP (adenosine 5"-triphosphate)c) glyceryl triacetate2. (15 points) a) If a sample the DNA is analyzed and found to contain 32% A and also 18%G, what must be the rest of the base composition?32% T and also 18% Cb) Using just the 20 usual amino acids, how plenty of different tripeptidescan it is in created?20 x 20 x 20 = 8,000c) In one electrophoresis experiment, i beg your pardon of the 20 typical aminoacids would migrate towards the anode (the an adverse electrode) in ~ pH 9 ?Lys and also Arg are the just amino acids that would certainly be positively chargedat pH 9. They have actually isoelectric points over 9.3. (15 points) The surname for the amino acid threonine comes from itssimilarity in framework to the street D-threose, presented below.Write the framework for threonine in a Fischer estimate that clearlyshows its similarity come D-threose. Identify each stereocenter in threonineas R or S. Just one other amino acid (of the 20 common ones in her table) hastwo stereocenters. I beg your pardon one? compose its framework with both stereocentersin the S configuration.4. (15 points) few of the three-letter codes in the codon table canbe deduced by use of straightforward nucleic mountain polymers that are easy to make.For example, if poly-U is fed to the bacteria E. Coli, an excess of theamino acid phenylalanine appears. Explain.The codon UUU equates as PheWhat amino acids would be supposed from poly-G, poly-C, and poly-A?The codon GGG equates as GlyThe codon CCC translates as ProThe codon AAA equates as LysWhat amino acids would be supposed from a regular alternating copolymerof A and C (i.e., ACACACACACACAC ) ?The codon ACA equates as ThrThe codon CAC converts as His5. (15 points) consider an unknown heptapeptide consist of of thefollowing amino acids: Arg, Asp, His, Ile, Phe, Tyr, ValDeduce its main structure from the adhering to data:the N-terminus is Aspthe C-terminus is Phechymotrypsin cleaves it to a tripeptide and also a tetrapeptide, A andBA has actually Ile in ~ its N-terminus and also Phe at its C-terminusB have the right to be partially hydrolyzed to provide dipeptides Arg Val, AspArg andValTyrAsp Arg Val Tyr Ile His PheUse the amino acids in this peptide to show the adhering to aspectsof tertiary structure. Draw just the specific side chain frameworks involved.a) ionic attraction b) H-bondingseveral possibilities, including: 6. (10 points) The framework of the male hormone androsterone is shownbelow. Finish the framework on the right by properly locating each ofthe seven substituents that are specifically presented on the left structure.Identify every substituent together either axial or equatorial (use A or E).all substituents are axial7. (15 points) Glutamic acid has actually two carboxylic acid groups with differentpKa values.


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The structure is displayed in its completely protonated form below, withits 3 pKa values. Introduce to the pH diagram below, create the structuresof the major forms that would be intended in equipment within each of thepH ranges marked A, B, C, and also D.Explain why the 2 carboxylic acid teams have various pKa values.The -COOH team closer come the -NH3+ team is a stronger acid becauseof the electron-withdrawing impact of the -NH3+ group.