LIFE SCIENCE

Detailed explanation-1: -The other common secondary structure is the beta-pleated sheet. In this structure, two different regions of a polypeptide chain lie side by side and are bound by hydrogen bonds. They make up the core of many globular proteins.

Detailed explanation-2: -Hydrogen bonding between amino groups and carboxyl groups in neighboring regions of the protein chain sometimes causes certain patterns of folding to occur. Known as alpha helices and beta sheets, these stable folding patterns make up the secondary structure of a protein.

Detailed explanation-3: -An -helix secondary structure is stabilized by hydrogen bonds between carbonyl oxygen and the amino group of every third residue in the helical turn with each helical turn consisting of 3.6 amino acid residues (Fig. 10.1A). The side chain of amino acids is projected outward from the outer helical surface.

Detailed explanation-4: -Hydrogen bonds Lots of amino acids contain groups in the side chains which have a hydrogen atom attached to either an oxygen or a nitrogen atom. This is a classic situation where hydrogen bonding can occur. For example, the amino acid serine contains an-OH group in the side chain.

Detailed explanation-5: -For example, collagen forms part of the matrix upon which cells are arranged in animal tissues. The fibrous protein keratin forms structures such as hair and fingernails. The structures of keratin illustrate the importance of secondary structure in giving proteins their overall properties.