2. Proteins

3. Protein Basics Used in variety of cellular functions Made of smaller amino acids Only 20 amino acids… but thousands of proteins –Exact arrangement of amino acids determines protein leucinevalineglycinealanineleucine histi- dine aspara- gine serineproline = protein A leucinevalineglycinealanineleucine histi- dine aspara- gine serineproline = protein B leucinevalineglycinealanineleucine = protein C

4. Amino Acid Structure 5 basic parts 1) Central C atom 2) Amino group (NH2) 3) H 4) Carboxyl group (COOH) 5) R group Monomer: Amino acid Polymer: Protein

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. 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

8. 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

9. Kobe Kuiz 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?