University:
York University
Course:
SC/BIOL 2021 | Cell Biology
Academic year:

2023
Views:

111

Pages:

2
Author:

Nick T.

Proteins Summary - Most complex + functions - Support - Defense - enzymatic functions - Transport - Movement Monomer: Amino Acids Amino acids become connected in linear polymers for a specific Sequence this String is called a polypeptide. Structure of Amino acids Amino group - Carbon - Carboxyl group R group this is always different "sidechain" can function as can function as an acid a base There are 20 different Side chains AT PH-7 the amino + carboxyl group are ionized. Amino gains a proton, Carboxy loses a proton Charged Charged Zwitterion: Hybrid atom -> has cations + Anions L-Amino Acids -> use these more commonly D-Amino Acids -> Isomers of L -> Only Glycine doesn't 19/20 Amino acids have isomers attached to carbon. Has -H x2 Proteins Subdivisions of Amino Acids Polar will have oxygen in the R-group nonpolar Mostly C and H -not very reactive no charged or partial charges (uncharged) polar partial charges - allow H-bonding (charged) All except Cysteine won't have oxygen in 'R-group' Amino acids are linked by peptide bonds Residues individual amino acids C terminus Carboxyl group end (right) N terminus Free amino group end (left) STRUCTURES PRIMARY Amino acid Sequence SECONDARY • Alpha helix -H bonds all along Same Strand wrapped to minimize exposure of Hydrophobic •Beta Sheets -H bonds all along diff. parts of Strang Holding Sheets together TERTIARY •Hydrogen Bond •Ionic Bonds •Hydrophobic bond •Disulfid ends only in cysteine QUATERNARY • 2+ polypeptides w/ own Pr. Sc. Tr. Structures Dimer: 2 P.Ps w/ identical lvl 1,2,3 but only function once together Heterotetramer Diff 1,2,3 Structu Denaturation unfolds + Secondary + tertiary Structure N-bonds broken