13.2) Draw the line bond structure for the general form of an amino acid using "R" to represent the side chain. Draw the N- and C- terminus groups using the forms that are predominant at physiological pH (pH=7.4). Include lone pairs in your drawing. quaternary ammonium group Quaternary ammonium groups that are attached to the a-carbons of amino acids have pKą values of about 9.5, therefore, at pH = 7.4, the acid form (quaternary ammonium group) is predominant. ANSWER: H H H-N-C H R :0: || C carboxylate group The pK values of amino acid carboxyl groups are between 2 and 5 (depending on which amino acid), therefore, at pH = 7.4, the base form (carboxylate ion) is predominant. R-group (called "side-chain")

Researchers discover a new amino acid. Its R-group exclusively has hydrogen and carbon atoms. What behavior will this amino acid show? O Relative to the amino acids found in organisms, its interactions with water will be very high. It is hydrophilic. Relative to the amino acids found in organisms, its interactions with water will be intermediate. It is hydrophobic.

Identify the part of a generic amino acid that reacts with base and the part that reacts with acid. Briefly explain your answer.Hint: Draw Lewis structures for ammonia (NH 3) and acetic acid (CH 3COOH).

For the amino acid alanine, the major species in solution at pH 7 is the zwitterionic form, which has a negatively charged carboxylic acid group and a positively charged amino group. There is a less common neutral form in which neither group is charged. The carboxylic acid group of alanine has a p?a of 3 The amino group of alanine has a p?a of 8 Estimate the ratio of the concentration of the neutral amino acid species to the zwitterionic species at pH 7.   __?__x10^?

Explain why casein precipitates when vinegar is added. Why was milk or raw egg once used as an antidote in cases of heavy metal poisoning? Based on your isolated yield of casein, how many grams of the protein are in one 200 g glass of milk? Which of the solutions contained amide bonds? Which test tells you this? Which of the solutions contained compounds with primary amino groups? Which test tells you this? Describe two examples of protein folding patterns and identify what level of protein structure they belong to. What other reagents might you use besides ferric chloride to test affinity for metal ions?

H N. NH3 'N' NH3 NH Part A What are the amino acids in kyotorphin? Spell out the full names of the compounds. Enter your answers separated by a comma. Submit Request Answer Part B How would you name the dipeptide in kyotorphin? Spell out the full name of the compound.

What do your findings suggest about the stability of proteins in the presence of organic solvents?

Which amino acid is this? H₂N- hono CH-C-OH CH₂

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