2. Proteins

3. Protein Basics Used in variety of cellular functions Made of smaller amino acids –Monomer: Amino acid –Polymer: Polypeptide (Protein) 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 acids (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. What differs between these amino acids? Notice alanine’s different R group Notice Valine’s different R group Notice leucine’s different R group Notice methionine’s different R group Notice isoleucine’s different R group R group for glycine

6. Enzymes Types of proteins Enzyme: Lowers the energy needed to start chemical reactions –ex: Break down food 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 Starch

7. REview 1)What are the smaller monomers that make proteins called? 2)How many different amino acids exist? 3)How does each amino acid differ? 4)The NH2 part of the amino acid is called the ____ group. 5)The COOH part of the amino acid is called the ____ group. 6)Which group of proteins help to start chemical reactions? 7)What can cause an enzyme to denature? 8)Explain the lock and key analogy as it relates to enzymes.