AP BIOLOGY

Detailed explanation-1: -Secondary structure refers to regular, recurring arrangements in space of adjacent amino acid residues in a polypeptide chain. It is maintained by hydrogen bonds between amide hydrogens and carbonyl oxygens of the peptide backbone. The major secondary structures are -helices and -structures.

Detailed explanation-2: -Within a protein, multiple amino acids are linked together by peptide bonds, thereby forming a long chain. Peptide bonds are formed by a biochemical reaction that extracts a water molecule as it joins the amino group of one amino acid to the carboxyl group of a neighboring amino acid.

Detailed explanation-3: -The secondary structure arises from the hydrogen bonds formed between atoms of the polypeptide backbone. The hydrogen bonds form between the partially negative oxygen atom and the partially positive nitrogen atom.

Detailed explanation-4: -Hydrogen bonds between polar amine and carboxyl groups alleviate the desolvation penalty of those groups as they become buried in protein’s native structure. This, in turn, gives rise to the familiar protein secondary structures, such as alpha-helices and beta-sheets.