Proteins

Protein Basics Made of C,H,O, N SPONCH Monomers = amino acids - 20 different types of amino acids used to make proteins Proteins are the polymer also called a polypeptide

Meet the monomer –Amino acid 3 main parts - Amino group NH2 - Carboxyl group COOH - R group (side chain) each of the 20 types of amino acids have a unique R group

Proteins form from chains of amino acids Proteins vary in length – can be 1,000s of amino acids long Protein

Proteins Shape A protein’s shape is determined by the order that amino acids are joined in The shape of a protein determines its function Hemoglobin antibody enzymes polymerase

Protein Structure Four Levels of Structure allow for any shape 2-28

Protein Structure – Primary Structure Primary structure is the order of the amino acids that make up a protein. - the interactions of the R groups on each amino acid cause the molecule to bend and fold – different arrangements create different shapes - as a result- the order of amino acids determines the shape of the protein - shape determines function - changing a single amino acid can change a protein’s shape.

Protein Structure- Secondary Structure The folding proteins often assume one of two general shapes – pleated sheets or an alpha helix these are the protein’s secondary structure. - hydrogen bonds between amino acids stabilize the secondary structure Alpha Helix

Protein Structure – Tertiary Structure The coiled or pleated structures continue to fold until they form a complex three dimensional structure. - most proteins are completed at this stage and are fully functioning proteins. Remember: Shape determines function

Protein Shape-Quaternary Structure Some more complex proteins are assembled from two or more protein molecules. - Insulin – 2 forms – 2 proteins or 6 proteins - Hemoglobin – 4 proteins

Protein Functions Proteins are the Worker Molecules of Living Things Enzymes - proteins that allow chemical reactions to occur in living things Antibodies – proteins that protect the body from infection Structure – cytoskeleton, hair, nails, muscles, spider web, silk, feathers ,horns, hooves etc…. Hormones – chemical messengers Cell membrane – proteins can act as channels through the cell membrane - receptor proteins found on membrane transmit signals to the inside of cells Hemoglobin – protein found in blood that carries oxygen

Proteins can be Denatured Denatured proteins are proteins that lose their shape - if they lose their shape, they also lose their - What can cause a protein to become denatured? Exposure to: A Strong Acid A Strong Base Heat An organic solvent: Alcohol or Acetone - Denatured proteins can lose quaternary, tertiary and secondary structure - Primary Structure is left untouched … Function

Denatured Proteins

Vocabulary for the Protein Pro Polypeptide R – Group Peptide Bond Primary Structure Secondary Structure Tertiary Structure Quaternary Structure Enzymes Antibodies Cell Membrane Proteins Hormones Denatured Protein 4 things that denature proteins