CChheemm 44334433HOMEWORK#1 Name : 1. For the amino acid lysine, the pKa’s for the various acidic and basic groups are given below:(i) Draw the dominant structure found at pH values of 1, 5 and 10.(ii) Estimate, showing your method, the isolelectric point for Lysine(iii) Calculate, showing your method, the pH at which 50% of the molecules have a +2 netcharge and 50% have a +1 net charge2. (i) Table salt dissolves spontaneously in water as shown in the diagram below. Explain all of the factors that contribute to this process.(ii) Explain the observation that at pH of 7 tryptophan crosses a cell membrane about a1000 times more slowly than the closely related molecule indole below:tryptophanCαNHNH2OHOindoleNH(CH2)4H2N COOH2HNPKa=10.0PKa=2.2PKa=9.0For Questions 3 indicate all answers (i) through (v) that are correct.3. For the follwing pair of molecules:(i) at physiological pH naphthol will pass through the membrane bilayer faster than phenol(ii) at physiological pH phenol will pass through the membrane bilayer faster than naphthol(iiii) an aqueous solution of pH=11 will dissolve both naphthol and phenol(iv) an aqueous solution of pH=6 will dissolve both naphthol and phenol(v) at physiological pH=9 naphthol will pass through the membrane bilayer slower than phenolComment2-naphtholOHphenolOHPKa = 10.0PKa =
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