InterviewSolution
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InterviewSolution
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Question : Briefly describe the types of groups participating in the structure of amino acids. |
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Answer» Solution :Amino acids are organic COMPOUNDS containing an amino group and acidic group as substituents on the same CARBON i.e. a-carbon. Hence, they are called a-amino acids. There are four substituent groups occupying the four valency positions. These are hydrogen, carboxyl group, amino group and a variable group designated as R group. The R group in these proteinaceous amino acids could be a hydrogen (amino acid glycine), a methyl group (alanine), hydroxyl methyl (serine) etc. `underset("Glycine")(H-underset(H)underset(|)overset(COOH)overset(|)C-NH_(2)), underset("Alanine")underset(CH_(3))underset(|)overset(COOH)overset(|)(H-C-NH_(2)), underset("Serine")underset(CH_(2)-OH)underset(|)overset(COOH)overset(|)(H-C-NH_(2))` The chemical and physical properties of amino acids are essentially of the amino, carboxyl and the R FUNCTIONAL groups. Based on number of amino and carboxyl groups, there are acids (e.g., glutamic acid), basic (lysine) and neutral (valine) amino acids. Similarly, there are aromatic amino acids (tyrosine, phenylalanine, tryptophan). A particular property of amino acids is the ionizable nature of -`NH_2` and -COOH groups. Hence in solutions of different PHS, the structure of amino acids changes. `underset("B is called zwitterionic form")(H_(3)^(+)N - overset(R)overset(|)CH-COOH) |
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