2. PROTEINS Made of carbon, oxygen, hydrogen, and nitrogen (CHON) Monomers of proteins are amino acids Monomers of fats are: triglycerides (glycerol and 3 fatty acids) Monomers of carbohydrates are: monosaccharides Polymers of amino acids are proteins Amino acids make up proteins Just like atoms make up elements Just like beads make up a necklace Sneak peek: There are 20 amino acids that code for all proteins

3. PROTEINS How do you think amino acids link together? DEHYDRATION SYNTHESIS What is lost during this process? WATER How are lipids and carbohydrates linked together? DEHYDRATION SYNTHESIS What is lost during this process? WATER How are lipids, carbohydrates, and proteins broken into monomers? HYDROLYSIS What is added to break apart the polymers into monomers? Water is added

4. PROTEINS Amino acids are linked together through dehydration synthesis The bonds that hold the amino acids together are PEPTIDE BONDS Peptide bonds are covalent (sharing) bonds created by the process of : Dehydration synthesis 2 amino acids that are linked by a peptide bond is called a DIPEPTIDE More than 2 amino acids are called POLYPEPTIDES

5. PROTEIN DENATURATION Denaturation= changing its nature. Process where polypeptide (protein) chains unravel Changes their shape, which then changes their function Ex: when you cook an egg, what happens to the egg whites? Egg whites (protein) become denatured (unraveled)because of the heat. As a result, the egg whites become solid. Can egg whites go back to their original form? No because the proteins are denatured (unraveled chains).

6. 7 classes of PROTEINS 1. Structural proteins Ex: hair & tendons 2. Contractile proteins Ex: provide muscular movement 3. Storage proteins Ex: egg whites 4. Defensive proteins Ex: antibodies 5. Transport proteins Ex: hemoglobin 6. Signal proteins Ex: certain hormones  serve as messengers 7. ENZYMES

7. ENZYMES 7 th class of proteins Catalyst= increases the rate of a reaction without itself being changed into a different molecule Enzyme= catalyst Does not add energy to a reaction Speeds up reaction by lowering activation energy barrier

8. ENZYMES Ex: digestive enzymes that help break down food Ex: sucrase (enzyme) breaks down sucrose (table sugar) by hydrolysis (adds H 2 0)

9. ENZYMES Substrate= substance that the enzyme acts on or a reactant in a chemical reaction In other words, a substrate (sucrose) is being broken down by the enzyme (sucrase) Active site= part of the enzyme where the substrate fits Ex: lock and key= key fits perfectly into lock. Lock= enzyme Key= substrate Each enzyme (lock) is fit for a specific substrate (key).