2. 1 Proteins Read pgs. 40-50, do #s 19-28 Learning Goal: I will understand the 4 levels of organization of proteins (primary, secondary, tertiary & quaternary), what the forces are causing each, what the protein monomer subunits are, what an amino acid is, and what causes proteins to lose their functionLearning Goal: I will understand the 4 levels of organization of proteins (primary, secondary, tertiary & quaternary), what the forces are causing each, what the protein monomer subunits are, what an amino acid is, and what causes proteins to lose their function

3. 2 Proteins (Polypeptides) peptide bonds polypeptidesAmino acids (20 different kinds of aa) bonded together by peptide bonds (polypeptides). Six functions of proteins:Six functions of proteins: 1.Storage:albumin (egg white) 2.Transport: hemoglobin 3.Regulatory:hormones 4.Movement:muscles 5.Structural:membranes, hair, nails 6.Enzymes:cellular reactions

4. Amino Acid Amine group acts like a base, tends to be positive. Carboxyl group acts like an acid, tends to be negative. “R” group is variable, from 1 atom to 20. Two amino acids join together to form a dipeptide. Adjacent carboxyl and amino groups bond together.

5. Some Amino Acids

6. Some More Amino Acids

7. Still More Amino Acids

8. Amino Acids NOTE: You need to know this table HydrophilicHydrophobic

9. Formation of a Dipeptide Dehydration synthesis

10. Amino Acid + Amino Acid --> Dipeptide Amino Acid + Dipeptide --> Tripeptide A.A. + A.A. + …..+ Tripeptide --> Polypeptide

11. 10 Primary Structure peptide bonds (straight chains) Amino acids (monomers) bonded together by peptide bonds (straight chains) aa1aa2aa3aa4aa5aa6 Peptide Bonds Amino Acids (aa)

12. Levels of Organization PrimaryPrimary structure –Amino acid sequence of the protein SecondarySecondary structure –H bonds in the peptide chain backbone  -helix and  -sheets TertiaryTertiary structure –Non-covalent interactions between the R groups within the protein QuaternaryQuaternary structure –Interaction between 2 polypeptide chains

13. Levels of Protein Structure

14. 13

15. Protein Folding 2 regular folding patterns have been identified – formed between the bonds of the peptide backbone  -helix – protein turns like a spiral – fibrous proteins (hair, nails, horns)  -sheet – protein folds back on itself as in a ribbon – globular protein

16.  Sheets Stabilized by H- bonds Can be of 2 types –Anti-parallel – run in an opposite direction of its neighbor (A) –Parallel – run in the same direction with longer looping sections between them (B)

17.  Helix Stabilized by H bonds The  helix is a tight coil a framework for structural proteins such as nails and skin

18. Tertiary Structure 17

19. Protein Denaturation -change in the 3D structure of a protein -Causes a loss of protein function (due to change in temperature, pH, etc) Functional protein Protein is no longer functional

20. 19 How Did We Do? Learning Goal: I will understand the 4 levels of organization of proteins (primary, secondary, tertiary & quaternary), what the forces are causing each, what the protein monomer subunits are, what an amino acid is, and what causes proteins to lose their functionLearning Goal: I will understand the 4 levels of organization of proteins (primary, secondary, tertiary & quaternary), what the forces are causing each, what the protein monomer subunits are, what an amino acid is, and what causes proteins to lose their function