Modified Mastering Chemistry with Pearson eText -- Standalone Access Card -- for Biochemistry: Concepts and Connections
1st Edition
ISBN: 9780133882797
Author: Dean R. Appling, Spencer J. Anthony-Cahill, Christopher K. Mathews
Publisher: PEARSON
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Chapter 2, Problem 15P
The anno acid arginine ionizes according to the following scheme:
a. Calculate the isoelectric point of arginine. You can neglect contributions from form l. Why?
b. Calculate the average charge on arginine when pH = 9.20. (Hint: Find the average charge for each ionizable group and sum these together)
c. Is the value of average charge you calculated in part b reasonable, given the pl you calculated part a? Explain your answer.
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The amino acid arginine ionizes according to the following scheme: (a) Calculate the isoelectric point of arginine. You can neglect contributionsfrom form I. Why?(b) Calculate the average charge on arginine when pH = 9.20.(c) Is the value of average charge you calculated in part b reasonable, giventhe pI you calculated in part a? Explain your answer.
The amino acid arginine ionizes according to the following scheme: (a) Calculate the isoelectric point of arginine. You can neglect contributions from form I. Why? (b) Calculate the average charge on arginine when pH = 9.20. (c) Is the value of average charge you calculated in part b reasonable, given the pI you calculated in part a? Explain your answer
For the following pentapeptides: Ser-Glu-Gly-His-Ala and Gly-His-Ala-Glu-Ser
A. Compute their isoelectric pH (pI). Show full solution. Use standard pKa values.
B. Do these peptides with the same amino acid composition have different net charges at pH 7.0? Explain briefly.
C. Would you expect the titration curves of the two peptides to differ? Why or Why not?
Chapter 2 Solutions
Modified Mastering Chemistry with Pearson eText -- Standalone Access Card -- for Biochemistry: Concepts and Connections
Ch. 2 - Suppose a chloride ion and a sodium ion are...Ch. 2 - Draw two different possible hydrogen-bonding...Ch. 2 - Prob. 3PCh. 2 - 4. What is the pH of each of the following...Ch. 2 - Prob. 5PCh. 2 - The weak acid HA is 2% ionized (dissociated) in a...Ch. 2 - 7. Calculate the pH values and draw the titration...Ch. 2 - What is the pH of the following buffer mixtures?...Ch. 2 - a. Suppose you wanted to make a buffer of exactly...Ch. 2 - Prob. 10P
Ch. 2 - You need to make a buffer whose pH is 7.0, and you...Ch. 2 - Describe the preparation of 2.00 L of 100 glycine...Ch. 2 - Carbon dioxide is dissolved in blood (pH 7.4) to...Ch. 2 - What is the molecular basis for the observation...Ch. 2 - The anno acid arginine ionizes according to the...Ch. 2 - It is possible to make a buffer that functions...Ch. 2 - A student is carrying out a biological preparation...Ch. 2 - Histidine is an amino acid with three titratable...Ch. 2 - Prob. 19PCh. 2 - Prob. 20PCh. 2 - Prob. 21P
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- The β chains of HbA and HbS were treated with trypsin, and the sequence of the N-terminal tryptic peptides are as given below. Do these peptides separate from each other in an electric field if the pH is 7.0? Explain in detail the reasoning behind your answer and include your calculations for the charge of each peptide in your answer.arrow_forwardDraw Ramachandran plot for: a) regular secondary structure with Φ = 60-65 and Ψ = 60-80 b) regular secondary structure with Φ = -170 and Ψ = 170 c) intrinsically disordered proteins d) explain why these Ramachsndran plots will be different, and what secondary structures are described in A and in Barrow_forwardThe melting curve for the polyribonucleotide poly(A) is shown below. (a) Explain why absorbance increases with increasing temperature. (b) Why does the shape of the curve differ from the one shown in Fig. ?arrow_forward
- Let’s consider histidine as a free amino acid in aqueous solution. a) Draw the most likely structure of histidine under biochemical standard state conditions. b) Given that free histidine has the following three pKa values, assign each to its corresponding acidic hydrogen or conjugate base in your structure from part a). pKa1 = 1.7; pKa2 = 6.2; and pKa3 = 9.1 c) For each pKa, give the corresponding expression for the equilibrium constant. It helps to write out the chemical equation for each. d) Create a speciation diagram for histidine by plotting Xi vs pH from pH = 4 to pH = 8 where Xi is the mole fraction of the two histidine species involved in the K2 equilibrium in part c).arrow_forwardyou have isolated the following peptide: His-Ser-Arg- Ala-Glu- Leu- Pro- Gly Calculate the approximate charge of the peptide at Ph 1, 3, 5, 8, 11, 14 AND what is the PI of this peptide?arrow_forwardClassify the fatty acid with the following structural formula in the ways indicated. a. What is the type designation (SFA, MUFA, or PUFA) for this fatty acid? b. On the basis of carbon chain length and degree of unsaturation, what is the numerical shorthand designation for this fatty acid? c. To which "omega" family of fatty acids does this belong? d. What is the "delta" designation for the carbon chain double-bond locations for this fatty acid? Note: There are 2 items in the photo.arrow_forward
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