2. Proteins

3. Protein Basics Used in variety of cellular functions Made of smaller amino acids –Monomer: Amino acid –Polymer: Protein (often multiple polypeptides) Only 20 amino acids… but thousands of proteins –Exact arrangement of amino acids determines the protein leucinevalineglycinealanineleucine histi- dine aspara- gine serineproline = protein A leucinevalineglycinealanineleucine histi- dine aspara- gine serineproline = protein B leucinevalineglycinealanineleucine = protein C Amino acid (monomer)

4. Amino Acid Structure 5 basic parts 1) Central C atom 2) Amino group (NH2) 3) H 4) Carboxyl group (COOH) 5) R group Only 20 amino acids… Each has different R group

5. Amino Acid Structure 5 basic parts 1) Central C atom 2) Amino group (NH2) 3) H 4) Carboxyl group (COOH) 5) R group Only 20 amino acids… Each has different R group C H H C OH O N H H Amino acid: Glycine R

6. R Amino Acid Structure 5 basic parts 1) Central C atom 2) Amino group (NH2) 3) H 4) Carboxyl group (COOH) 5) R group Only 20 amino acids… Each has different R group C H C OH O N H H Amino acid: Alanine HH H C

7. R Amino Acid Structure 5 basic parts 1) Central C atom 2) Amino group (NH2) 3) H 4) Carboxyl group (COOH) 5) R group Only 20 amino acids… Each has different R group C H C OH O N H H Amino acid: Valine CH C C HH H H H H

8. What differs between these 6 amino acids? Each “R” group is different

9. N H How do amino acids bond? Dehydration synthesis! Peptide Bonds: link amino acids to form a chain (polypeptide) Polypeptide bends & folds based on R group attractions R C H C OH O N H H R C H C O H H2OH2O Peptide bond

11. N H How are proteins broken down? Hydrolysis! Peptide bond is broken with help of water and enzymes Occurs during the digestion of food R C H C OH O N H H R C H C O H H2OH2O

12. Enzymes Types of proteins Enzyme: Lowers the energy needed to start a chemical reaction –Breaking down food –Build other proteins Sensitive to pH, temp –ex: If high fever: enzymes lose ability to work Very specific in actions –ex: Amylase: Breaks starch into simple sugars Reusable glucose Enzyme amylase glucose

13. Kobe Kuiz 1)What are the smaller monomers that make proteins called? 2)How many different amino acids exist? 3)How are proteins different from polypeptides? 4)How does each amino acid differ? 5)The NH2 part of the amino acid is called the ____ group. 6)The COOH part of the amino acid is called the ____ group. 7)Which group of proteins help to start chemical reactions? 8)How is dehydration synthesis and hydrolysis different?