BIOL 1441 1st Edition Lecture 8 Outline of Last Lecture I. PolysaccharidesII. Lipidsa. Fatsb. Phospholipidsc. SteroidsIII. ProteinsOutline of Current Lecture I. Proteins a. Side groupsb. Levels of protein structureII. Nucleic acidsa. structureCurrent LectureI. Proteins a. Side groups:i. Nonpolar Amino Acids1. Hydrophobic2. Methyl groupii. Polar amino acidsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.1. Hydrophilic2. Hydroxyl, carbonyl, amino etc. groupsiii. Electrically charged amino acids1. Acidic or basica. Acidic: carboxyl group (negative charge)b. Basic: amino group (positive charge)c. hydrophilicb. Polypeptidesi. Unique linear sequence of amino acids1. Range in length from few AAs - more than a thousandii. Amino acids (AAs) linked by peptide bonds1. Join by dehydration rxn- water removala. Carboxyl joins to an amino group=peptide bondc. 4 Levels of Protein Structurei. Primary structure- sequence of amino acids1. AA sequence is like the order of letters in a long word 2. Determined by inherited genetic information3. PEPTIDE BOND (COVALENT)4. ORDER IS IMPORTANT (amino and carboxyl end)ii. Secondary structure- coils & folds in the polypeptide chain due to H-bonds in backbone1. Either forms a β pleated sheet or2. An α helix3. BOND: HYDROGEN BONDS4. BOND FORMING BETWEEN BACKBONEiii. Tertiary structure- interactions among various side chains (side groups)1. EVERY TYPE OF BOND2. BOND BETWEEN SIDE GROUPSiv. Quaternary structure- multiple polypeptide chains1. Results when 2 or more polypeptide chains form one macromolecule2. Collagen- consists of 3 polypeptides coiled like a rope3. Hemoglobin- consisting of 4 polypeptides: 2 a-chains & 2 b-chains4. ALL TYPES OF BONDSv. ALL PROTEINS HAVE LEVELS 1-3 BUT NOT ALL HAVE 4TH LEVELd. Sickle-Cell Diseasei. Inherited blood disorder- results from single AA substitution in hemoglobinii. Substitution of an amino acide. Protein Conformationi. Primary structure, physical & chemical conditionsii. Alternations in pH, salt concentration & temperature can cause a protein to unravel (unfold)iii. Denaturation- loss of a protein’s native conformation1. Unfolded protein (still in primary structure-peptide bonds don’t break)f. Protein-Folding Problemi. Very hard to predict a protein’s conformation from primary structureii. Proteins go through several stages on their way to a stable conformation iii. Chaperonins- proteins that assist the proper folding of other proteins1. Prevents outside influences from affecting protein polypeptides while they fold togetherII. Nucleic Acidsa. 2 types of nucleic acids:i. Deoxyribonucleic acid (DNA)ii. Ribonucleic acid (RNA)b. DNA directs its own replication (only macromolecule)c. DNA directs synthesis of messenger RNA (mRNA) and controls protein synthesisi. Nucleotide= 1 phosphate group + 1 ribose sugar + 1 type of nitrogen base1. Phosphate group-negative charge--- DNA = negative2. Classify by type of nitrogen base3. Nitrogenous basea. 2 types:i. Pyrimidines: 6 membered ring1. CYTOSINE, THYMINE (DNA), URACIL (RNA)2. C.U.T the Pie (pyrimidine)ii. Purines: 6 membered ring fused to 5 membered ring1. ADENINE, GUANINE4. Pentose sugar- 5 carbonsa. Deoxyribose (DNA)- deoxygenated riboseb. Ribose (RNA)d. Nucleotide polymersi. Nucleotides joined by covalent bonds that form between the –OH group on the 3´ carbon of 1 nucleotide and the phosphate on the 5´ carbon on the next1. Phosphate joining hydroxyl group coming off 3’ carbon2. Phosphodiester bond:a. Creates a backbone of sugar-phosphate units with nitrogenous basesii. DNA sequence is unique for each gene1. Genes encode proteins2. 1 DNA molecule includes many genes3. 23 pairs of chromosomese. DNA Double Helixi. 2 polynucleotides in helixii. 2 backbones run in opposite 5´ to 3´ directions from each other (antiparallel)iii. Nitrogenous bases in DNA form hydrogen bonds: 1. A always with T (U- RNA)2. G always with