BIOL 2457 1st Edition Lecture 5Outline of Last LectureI. Introduction to Chapter 2Outline of Current LectureI. Acids, Bases, and SaltsSA + WB = WA + SaltSB + WA = WB + SaltSA + SB = Water + SaltII. Maintaining pH: Buffer SystemsIII. The pH values of different parts of the body are maintained fairly constant by buffer systems, which usually consist of a weak acid and a weak base.a. Convert strong acids or bases into weak acids or basesb. Example: carbonic acid-bicarbonate buffer systemIV. Carbon & Its Functional GroupsV. Many functional groups can attach to carbon skeletona. Esters, amino, carboxyl, phosphate groups b. Very large molecules are called macromolecules (or “polymers” if all the monomer subunits are similar)VI. Isomers have the same molecular formulas but different structures (glucose & fructose are both C6H12O6)VII. CarbohydratesVIII. Carbohydrates provide most of the energy needed for life and include sugars, starches, glycogen, and cellulose.IX. Some carbohydrates are converted to other substances which are used to build structures and to generate ATP.X. Other carbohydrates function as food reserves.XI. Carbohydrates are divided into three major groups based on their size: monosaccharides, disaccharides, and polysaccharides XII. DisaccharidesXIII. Combining 2 monosaccharides by dehydration synthesis releases a water molecule.a. sucrose = glucose & fructoseb. maltose = glucose & glucosec. lactose = glucose &galactoseXIV. Polysaccharides are the largest carbohydrates and may contain hundreds of monosaccharides.XV. The principal polysaccharide in the human body is glycogen, which is stored in the liver or skeletal muscles.XVI. When blood sugar level drops, the liver hydrolyzes glycogen to yield glucose which isreleased from the liver into the bloodXVII. LipidsXVIII. Lipids, like carbohydrates, contain carbon, hydrogen, and oxygen; but unlike carbohydrates, they do not have a 2:1 ratio of hydrogen to oxygen.XIX. They have few polar covalent bonds a. Are hydrophobicb. Are mostly insoluble in polar solvents such as waterc. Combine with proteins (lipoproteins) for transport in bloodXX. TriglyceridesXXI. Triglycerides are the most plentiful lipids in the body and provide protection, insulation, and energy (both immediate and stored).a. At room temperature, triglycerides may be either solid (fats) or liquid (oils).b. Triglycerides provide more than twice as much energy per gram as either carbohydrates or proteins.c. Triglyceride storage is virtually unlimited.d. Excess dietary carbohydrates, proteins, fats, and oils will be deposited in adiposetissue as triglycerides.XXII. PhospholipidsXXIII. Phospholipids are important membrane components.XXIV. They are amphipathic, with both polar and nonpolar regions a. A polar headi. A phosphate group (PO4-3) & glycerol moleculeii. Forms hydrogen bonds with waterb. 2 nonpolar fatty acid tailsi. Interact only with lipidsXXV. SteroidsXXVI. Steroids have four rings of carbon atoms Steroids include a. Sex hormonesb. Bile saltsc. Some vitaminsd. Cholesterol, with cholesterol serving as an important component of cell membranes and as starting material for synthesizing other steroids.XXVII. ProteinsXXVIII. Constructed from combinations of 20 amino acids.a. Dipeptides - formed from 2 amino acids joined by a covalent bond called a peptide bondb. Polypeptide chains - formed from 10 to 2000 amino acids. XXIX. Formation of a Dipeptide BondXXX. Dipeptides formed from 2 amino acids joined by a covalent bond called a peptide bonda. Formed by dehydration synthesisXXXI. Polypeptide chains contain 10 to 2000 amino acids.XXXII. Protein Structural OrganizationXXXIII. Levels of structural organization include a. Primaryb. Secondaryc. Tertiaryd. Quaternary XXXIV. The resulting shape of the protein greatly influences its ability to recognize and bind to other molecules.XXXV. Denaturation of a protein by a hostile environment causes loss of its characteristic shape and function.XXXVI. Protein Structural OrganizationXXXVII. EnzymesXXXVIII. Catalysts in living cells are called enzymes.XXXIX. Enzymes are highly specific in terms of the “substrate” with which they react.XL. Enzymes are subject to a variety of cellular controls.XLI. Enzymes speed up chemical reactions by increasing frequency of collisions, lowering activation energy and properly orienting colliding molecules.XLII. DNA and RNAXLIII. Nucleic acids are huge organic molecules that contain carbon, hydrogen, oxygen, nitrogen, and phosphorus.XLIV. Deoxyribonucleic acid (DNA) forms the genetic code inside each cell and thereby regulates most of the activities that take place in our cells throughout a lifetime.XLV. Ribonucleic acid (RNA) relays instructions from the genes in the cell’s nucleus to guide each cell’s assembly of amino acids into proteins by the ribosomes.XLVI. The basic units of nucleic acids are nucleotides, composed of a nitrogenous base, a pentose sugar, and a phosphate