From examination of the molecular models i–v, choose the substance that
(a) can be hydrolyzed to form a solution containing glucose,
(b) is capable of forming a zwitterion,
(c) is one of the four bases present in DNA,
(d) reacts with an acid to form an ester,
(e) is a lipid. [Sections 24.6–24.10]
Step 1 of 5) We first combine the carboxyl group of alanine with the amino group of glycine to form a peptide bond and then the carboxyl group of glycine with the amino group of serine to form another peptide bond: Polypeptides are formed when a large number of amino acids 17302 are linked together by peptide bonds. Proteins are linear (that is, unbranched) polypeptide molecules with molecular weights ranging from about 6000 to over 50 million amu. Because up to 22 different amino acids are linked together in proteins and because proteins consist of hundreds of amino acids, the number of possible arrangements of amino acids within proteins is virtually limitless.The sequence of amino acids from the “N terminus” (that is, the amino end) to the “C terminus” (the carboxylic acid end) along a protein chain is called its primary structure and gives the protein its unique identity. A change in even one amino acid can alter the biochemical characteristics of the protein. For example, sickle-cell anemia is a genetic disorder resulting from a single replacement in a protein chain in hemoglobin. The chain that is affected contains 146 amino acids.
