PROTEINS AND NUCLEIC ACIDS

Protein Structure continued:

Proteins have 4 levels of structure
....1) Primary - refers to the amino acid sequence or the chain of amino acids. No proteins function at this level.
...2) Secondary - when R-groups begin interacting forming Hydrogen Bonds.  Typical secondary structure would be the ALPHA HELIX - which is shaped like a spring (hair) and the BETA SHEET - like an interlocking mat (silk).  Some proteins function at this level.
...3) Tertiary - When R-group interactioons begin to form complex complex globular structures.  Most proteins (like enzymes) function at this level.
...4) Quaternary - This is when more than one polypeptide forms a single protein - it is multiglobular.  Hemoglobin has 4 Heme groups that can each carry an O2 molecule.  A few very complex proteins function at this level.

DENATURATION - Happens when heat and/or change in pH interferes with the R-group interactions and the protein reverts back toward its primary structure.  This will alter or destroy the protein's function.

4. NUCLEIC ACIDS - Chemicals that are found mostly in the nucleus of cells that have phosphate groups (PO4's) and Nitrogenous Bases.  3 Types:
....a. DNA - Deoxyribonucleic Acid - Contains the Genetic information.