2. Proteins C, H, N, O, S 50% of the Dry Weight of Living Organisms
Function:
1. Structure  Hair, Fingernails, Cell membranes
2. Transport  Hemoglobin & Cell membranes
3. Regulatory  Protein Hormones
4. Catalysis  Enzymes
5. Locomotion  Muscles

3. Monomer General Structure
Monomer = Amino Acids

4. Generalized Amino Acid Structure
“Remainder Group”
“Amine Group”
“Acid Group”

5. “Dipeptide” = 2 amino acidsR R
In synthesis, one molecule loses an H+, one molecule loses an OH-.
“Dipeptide” = 2 amino acids R R
Peptide Bond

6. Peptide Bonds are POLAR, COVALENT Bonds

7. Proteins 22 different amino acids used to make all proteins
Each has a unique “R” group!
9 of these not made by body  must come from diet
Amino acids contain only C, H, N, O, S

8. What colour is the R group?

9. Levels of Organization
Primary 1○
Amino acids linked together
Peptide bonds join
Forms POLYPEPTIDE chain

10. Secondary 2○
b/c peptide bonds are polar, H-Bonding routinely occurs between amino acids.
Often, this will cause the chain coil up into a shape called an alpha helix. Layers called “ß-pleated sheets” can also form.
Folded sheet OR Helical appearance

11. Tertiary 3○
different types of bonding (covalent, ionic, hydrogen) between -R groups makes the alpha helix bend and turn
forms "globs"
final 3-D shape is very exact and precise
E.g. Enzymes

12. Quaternary 4○
More than one polypeptide arranged to take on unique structure
E.g. Insulin / Hemoglobin

14. Denaturation of Proteins

15. Denaturation of Proteins
Change in pH
High heat
Heavy metals
High salt concentration
Interfere with bonding of 2o & 3o structures
Destroys shape of the protein