BIOL 1441 1st Edition Lecture 8 Outline of Last Lecture I Polysaccharides II Lipids a Fats b Phospholipids c Steroids III Proteins Outline of Current Lecture I Proteins a Side groups b Levels of protein structure II Nucleic acids a structure Current Lecture I Proteins a Side groups i Nonpolar Amino Acids 1 Hydrophobic 2 Methyl group ii Polar amino acids These 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 Hydrophilic 2 Hydroxyl carbonyl amino etc groups iii Electrically charged amino acids 1 Acidic or basic a Acidic carboxyl group negative charge b Basic amino group positive charge c hydrophilic b Polypeptides i Unique linear sequence of amino acids 1 Range in length from few AAs more than a thousand ii Amino acids AAs linked by peptide bonds 1 Join by dehydration rxn water removal a Carboxyl joins to an amino group peptide bond c 4 Levels of Protein Structure i Primary structure sequence of amino acids 1 AA sequence is like the order of letters in a long word 2 Determined by inherited genetic information 3 PEPTIDE BOND COVALENT 4 ORDER IS IMPORTANT amino and carboxyl end ii Secondary structure coils folds in the polypeptide chain due to Hbonds in backbone 1 Either forms a pleated sheet or 2 An helix 3 BOND HYDROGEN BONDS 4 BOND FORMING BETWEEN BACKBONE iii Tertiary structure interactions among various side chains side groups 1 EVERY TYPE OF BOND 2 BOND BETWEEN SIDE GROUPS iv Quaternary structure multiple polypeptide chains 1 Results when 2 or more polypeptide chains form one macromolecule 2 Collagen consists of 3 polypeptides coiled like a rope 3 Hemoglobin consisting of 4 polypeptides 2 a chains 2 b chains 4 ALL TYPES OF BONDS v ALL PROTEINS HAVE LEVELS 1 3 BUT NOT ALL HAVE 4TH LEVEL d Sickle Cell Disease i Inherited blood disorder results from single AA substitution in hemoglobin ii Substitution of an amino acid e Protein Conformation i Primary structure physical chemical conditions ii Alternations in pH salt concentration temperature can cause a protein to unravel unfold iii Denaturation loss of a protein s native conformation 1 Unfolded protein still in primary structure peptide bonds don t break f Protein Folding Problem i Very hard to predict a protein s conformation from primary structure ii Proteins go through several stages on their way to a stable conformation iii Chaperonins proteins that assist the proper folding of other proteins 1 Prevents outside influences from affecting protein polypeptides while they fold together II Nucleic Acids a 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 synthesis i Nucleotide 1 phosphate group 1 ribose sugar 1 type of nitrogen base 1 Phosphate group negative charge DNA negative 2 Classify by type of nitrogen base 3 Nitrogenous base a 2 types i Pyrimidines 6 membered ring 1 CYTOSINE THYMINE DNA URACIL RNA 2 C U T the Pie pyrimidine ii Purines 6 membered ring fused to 5 membered ring 1 ADENINE GUANINE 4 Pentose sugar 5 carbons a Deoxyribose DNA deoxygenated ribose b Ribose RNA d Nucleotide polymers i 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 next 1 Phosphate joining hydroxyl group coming off 3 carbon 2 Phosphodiester bond a Creates a backbone of sugar phosphate units with nitrogenous bases ii DNA sequence is unique for each gene 1 Genes encode proteins 2 1 DNA molecule includes many genes 3 23 pairs of chromosomes e DNA Double Helix i 2 polynucleotides in helix ii 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 C