Biochemistry 1430 midterm (All Questions Answered Correctly)

Typical Van der Waals energies are about: correct answers 2-4 kJ/mol A possible drug to treat COVID-19 has been discovered and is known to be a weak acid. At the pH of blood (7.4) the concentrations of acid and conjugate base are 0.075 and 0.025 respectively. What is its pKa? correct answers 3.00 What is the [A-]/[HA] ratio whent he weak acid is in solution alone pH unit above its pKa? correct answers 10:1 What are the primary chemical components present in a phosphate buffer at pH 7.4? correct answers H2PO4- and HPO4-2 Citric acid is an important intermediate in glucose metabolism that contains three carboxylic acid groups, and is synthesized in mitochondrial matrix. The three pKa values for each of the carboxylic acids are 3.1, 4.8, and 6.4. What would the charge be on a citrate molecule formed in the mitochondrial matrix where the pH is 7.8? correct answers -3 Which of the following amino acids would most likely be soluble in a nonpolar solvent such as benzene? correct answers Val Amino acid side chain (R, variable) groups contain all of the following functional groups except: correct answers ether Which amino acid has a carboxyl group in its side chain? correct answers Glu What charged group(s) is/are present in glycine at a pH of 7? correct answers -NH3+ and -NH2+ Below is a list of five tripeptides. Which tripeptide is negatively charged at a physiological pH? correct answers Met-Asp-Glu In the formation of the alpha helix, the carbonyl group is connected by: correct answers a hydrogen bond not with a neighboring NH group, but with a NH group located at a distance of four amino acid residues from it. Which of the following proteins does NOT have Quaternary structure? correct answers Myoglobin All of the following would disrupt quaternary structure except: correct answers treating with ascorbic acid Which of the following secondary structures would you expect to find on the surface of a globular protein? correct answers alpha helix, beta sheet and loops between two alpha-helices as long as the polar and charged amino acid side chains face the surface of the protein