Your Name__________________________________ Midterm 1LS3 Section 2, Fall 2005 October 25, 2005 Question 1 (40 points): 1. (8 points) In a test tube containing a mixture of amino acids in a simple buffer solution, the amino acids do not generally form peptide bonds, but instead remain as free amino acids. Why is this? Briefly explain your answer with respect to both free energy and activation energy. 2. (8 points) The initiation and elongation of protein synthesis in a eukaryotic cell is a complicated process requiring a considerable input of energy. If the first two amino acids of a polypeptide chain are Methionine (Met) and Glutamine (Gln), how many ATP and GTP molecules must be hydrolyzed by the time a peptide bond is formed between these two amino acids? (The textbook figures of translation initiation and elongation are at the end of the exam, but please be aware that additional information may be needed to answer this question.) Met + Gln Met-Gln (linked to Gln tRNA) 1
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