Proteins

1. Proteins

2. 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 Protein Basics leucine valine glycine alanine leucine leucine histi- dine aspara- gine serine proline = Protein A valine leucine glycine alanine leucine leucine histi- dine aspara- gine serine proline = Protein B Amino acids (monomer) leucine valine glycine alanine leucine leucine = Protein C

3. 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

4. What differs between these amino acids? Notice alanine’s different R group Notice Valine’s different R group R group for glycine Notice leucine’s different R group Notice methionine’s different R group Notice isoleucine’s different R group

5. Enzymes Enzyme amylase glucose glucose glucose glucose • 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 Starch

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