Proteins Biomolecule #3

Protein Structure Elements: carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur and share the same general structure. Monomer of proteins are called amino acids. There are 20 different amino acids, and proteins are composed of various combinations. Polymer is 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 Please draw the monomer.

Protein Structure – Special Bond Amino acids join together to form proteins with a special bond called a peptide bond. Forms between the amino acid group of one amino acid and the carboxyl group of another Proteins are also called polypeptides because of this bond.

Proteins Shape A protein’s shape is determined by the order that amino acids are joined in The shape/structure of a protein determines its function Hemoglobin Antibody Enzymes Polymerase

Protein Shape Primary (a) – Straight chains Secondary (b) – Coils and Pleats Tertiary (c) – Bends and Folds Quaternary (d) – Globs

Protein Functions 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 the membrane transmit signals to the inside of the cell Hemoglobin – protein found in blood that carries oxygen

Enzymes Video

Enzymes Vocabulary Enzyme – catalysts that lowers the activation energy of a reaction (make the reaction go faster). Catalyst – something that speeds up the reaction Activation Energy – the amount of energy required for a reaction to “go” Substrate – the substance an enzyme acts on Active Site – where the substrate binds to the enzyme Denature – loses shape or can no longer be useful; can happen due to change in pH or temperature Inhibitors – thing that stops an enzyme from working

Enzymes Active Site Enzyme Substrate

Temperature and pH greatly effect enzymes. There is an optimal temp and pH for every reaction.

Enzymes Look at the following graph and determine the temperature at which this enzyme has the greatest rate of activity.

How do enzymes help you? Food Digestion DNA Copying: helicase and polymerase break and reform the bonds needed to make more DNA. amylase (found in your saliva) helps break down starch lipase helps break down fats in your body (lipids) Energy Production – many different enzymes are needed during cellular respiration to make ATP. lactase helps break down lactose in dairy products (carbohydrate) protease helps break down proteins in your body