University:
York University
Course:
BIOL 107 | Introduction to Cell Biology
Academic year:

2024
Views:

447

Pages:

2
Author:

Ciara T.

Carbon Based Molecules DNA → RNA → Protein Carbohydrates: Important for structural support, cell identity and energy storage Proteins: Most diverse class of molecules The basic unit of protein is the amino acid Primary structure of a protein is the AA sequence Changing even one AA can change the structure of a protein and thus its function Peptide Bond Formation Carboxyl group + Amino group → Peptide bond formation + H2O HN-C-H + H-N-C-H → HN-C-CN-C-O + H2O H HCH H Peptide CH σ bond Covalent bond Carboxyl group and Amino group link forms a dipeptide loses water Amino Acids are joined by peptide bonds N-terminus = Amino group C-terminus = Carboxyl group Reactive Four levels Primary - sequence of AA Secondary - H-bond btwn atoms of peptide backbone Tertiary - 3D orientation Quaternary - two or more polypeptide chains Secondary Structure Affects shape and function Tertiary Structure Interactions btwn R groups/or R groups and peptide backbone Bonds that drive the structure of proteins Hydrogen bonds Ionic bonds Disulfide bridges Hydrophobic interactions Quaternary Structure Involves more than one polypeptide Cro (dimer) 2 subunits Haemoglobin (tetramer) 4 subunits oxygen transport protein Proper folding is CRITICAL to protein function Unfolded protein - denatured (added), unfunctional