WGU Biochemistry C 785 Study Guide | all units covered exclusively

Unit 2 – Amino Acids, Peptide Bonds, Protein Structure  Amino Acid: building blocks of proteins  Monomer: single amino acid  Polymer: amino acid chain of linked monomers called polypeptides  Amino Group: N with at least 1 H, can be NH2 or NH3  Hydrogen Hat: between amino group and carboxyl group, attached to alpha carbon  Variable Group “side chain” “R”: unique portion of amino acid  Carboxyl Group: C with 2 attached O’s, can be COOH, or COO  Hydrophobic Amino Acid: consists only of carbons and hydrogens end in H, CH, CH2, CH3 – they are nonpolar –Hydrophobic interactions occurs between two nonpolar amino acids H, CH, CH2, CH4, are the weakest type of bond – but the most important type for protein structure – are broken with heat (increased temperature)  Polar Amino Acid: end in OH, NH, SH, create hydrogen bonds, can be broken by changes in pH or changes in salt concentration.  SH: Disulfide bond/bridge made by SH side chains, is strongest, fewest in number, and only broken with reducing agents  Peptide Bonds: form at amino group and carboxyl group, “loss of H2O”  Ionic Bonds: occurs between two amino acids with opposite charges (charged amino acids, -/+, negative is acidic positive is basic), are broken with pH changes or changes in salt concentration  Dehydration Synthesis: when two molecules are covalently bonded with loss of a water molecule (H20)  one provides hydroxyl group OH and the other provides hydrogen H.  Amino group and carboxyl group both give up something and then they bind and form a new bond  polymer chain  Hydrolysis: addition of a water molecule H2O to break a bond, breaks polymers  4 Levels of Protein Structure: Primary  linear chain of amino acids, Secondary  alpha helix and beta sheet shapes, create by Hydrogen bonds of polypeptide backbones Tertiary 3D, stabilized by side chains Quaternary  consists of two or more polypeptide chains, more than one subunit – tertiary and quaternary are mature structures that are properly folded.  Denaturation: high temperatures and various chemical treatments will denature a protein, causing it to lose its shape and ability to function “form=function”  it may renature when chemical and physical aspects of environment are restored to normal.