A peptide consisting of the amino acid sequence ARSRTA is immobilized on a nitrocellulose membrane and bathed in a buffered solution at pH 7. If a second peptide consisting of the same amino acid sequence is added to the solution, what direction will the peptide move?
A. accelerate away from the fixed peptide.
B. circle the fixed peptide along an equipotential electric field line.
C. accelerate towards fixed peptide.
D. remain in place while doubling the electrical potential at a point located at d/2 between the peptides.
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Given that the peptide has two basic amino acids at physiological pH, it will have a positive charge. Two positive charges will repel each other. The mobile charge will accelerate away from the fixed charge.
A. accelerate away from the fixed peptide. correct.
B. circle the fixed peptide along an equipotential electric field line. Incorrect. The soluble peptide will accelerate away from the fixed peptide in a direction defined by the shortest path between the charges.
C. accelerate towards the fixed peptide. Incorrect. Like charges repel each other.
D. remain in place while doubling the electrical potential at a point located at d/2 between the charges. Incorrect. The mobile peptide will accelerate away from the fixed peptide.
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