The naturally occurring opioid met-enkephalin is a peptide with the structure Tyr- Gly-Gly-Phe-Met. What is its net charge of this molecule in the body at pH 7. OA) +1 B) +2 Oco D) -1 OE) -2

For each of the following chemicals, name the general class they belong to, discuss their solubility in water and explain why they are/are not soluble in water: a) CH3(CH2)26COOH b) KCl c) CH3

c) Jean-François is studying a specific protein in a research laboratory. In previous experiments, he observed that this protein seems to function as a receptor protein on the surface of cells that recognizes a specific hormone involved in cell-cell communication. Jean-François prepares his final experiment, but makes a mistake in calculating how much HCl to add to one of his solutions to get the correct pH. He performs the experiment, and much to his surprise, he observes that his protein no longer seems to be recognizing the hormone anymore as he had observed in previous experiments. Propose a hypothesis that briefly explains (2-3 sentences) why the results of Jean-François’ experiment have changed. oportmost likely h beens dy the celyd must irst ir o nm cof the st omce MAnoncalest wanti patient Hewe umourcells Becnuse of falla anan intoindidual.cells. protein d) True or false: A mutation could cause the same change in Jean-François' experimental results as the change in pH described…

There is parts A-D for the picture provided. A) A peptide has the sequence, Arg-Cys-His-Tyr-Glu-Asn-Lys-Asp. What is the net charge at pH 1? Choices: -5 -4 -3 -2 -1 0 +1 +2 +3 +4 +5   B) A peptide has the sequence Arg-Cys-His-Tyr-Glu-Asn-Lys-Asp. What is the net charge at pH 5?   Choices: -5 -4 -3 -2 -1 0 +1 +2 +3 +4 +5   C) Same Peptide sequence, What is the net charge at pH8.5, (N-terminus is pronated) Choices:    -5 -4 -3 -2 -1 0 +1 +2 +3 +4 +5   D) A  peptide has the sequence, Arg-Cys-His-Tyr-Glu-Asn-Lys-Asp. What is the net charge at pH 13?   Choices: -5 -4 -3 -2 -1 0 +1 +2 +3 +4 +5   Thank You!