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ORGANIC CHEMISTRY Organic compounds always contain carbon and hydrogen. Inorganic compounds typically lack carbon. Organic Compounds • The chain of carbon atoms in an organic molecule is the carbon skeleton. • Functional groups are responsible for most of the chemical properties of a particular organic compound. Table 2.3.1 Organic Compounds • Small organic molecules can combine into large macromolecules. • Macromolecules are polymers consisting of many small repeating molecules. • The smaller molecules are called monomers. Organic Compounds • Monomers join by dehydration synthesis or condensation reactions. • Polymers are broken apart by hydrolysis or phosphorlysis Figure 2.8 CARBOHYDRATES, LIPIDS, PROTEINS, AND NUCLEIC ACIDS • BIOLOGICAL MOLECULES ARE ORGANIC COMPOUNDS • CARBOHYDRATES • FATS AND LIPIDS • PROTEINS • NUCLEIC ACIDS CARBOHYDRATES • MONOSACCHARIDES = SUGARS • DISACCHARIDES = SUGARS • POLYSACCHARIDES = STARCHES & CELLULOSE Carbohydrates • Are important for structure and as energy sources. • Consist of C, H, and O with the formula (CH2O)n Figure 2.8 Carbohydrates • Oligosaccharides consist of 2 to 20 monosaccharides. • Polysaccharides consist of tens or hundreds of monosaccharides joined through dehydration synthesis. • Starch, glycogen, dextran, and cellulose are polymers of glucose that are covalently bonded differently. • Chitin is a polymer of two sugars repeating many times. MONOSACCHARIDES • • • • • • GLYCERALDHYDE 3 PHOSPHATE ERYTHROSE 4 PHOSPHATE RIBOSE 5 PHOSPHATE GLUCOSE FRUCTOSE GALACTOSE Carbohydrates • Monosaccharides are simple sugars with 3 to 7 carbon atoms. Figure 2.8 STRUCTURAL ISOMERS • IDENTICAL MOLECULAR FORMULAS • DIFFERENT STRUCTURES Carbohydrates • Disaccharides are formed when two monosaccharides are joined in a dehydration synthesis. • The bond is a glycosidic bond • Disaccharides can be broken down by hydrolysis. Figure 2.8 DISACCHARIDES • MALTOSE—GLUCOSE + GLUCOSE • SUCROSE—GLUCOSE + FRUCTOSE • LACTOSE---GLUCOSE + GALACTOSE POLYSACCHARIDES • • • • STARCH GLYCOGEN CELLULOSE CHITIN STARCH • STORAGE MOLECULE IN PLANTS GLYCOGEN • STORAGE MOLECULE IN ANIMALS CELLULOSE • MOST ABUNDANT CARBOHYDRATE • PLANT • ALGAE CHITIN • FUNGI CELL WALLS • EXOSKELETON OF INSECTS GLUCOSAMINE & GALACTOSAMINE • MODIFIED CARBOHYDRATES • HYDROXIDE GROUP REPLACED BY AMINE GROUP LIPIDS • • • • • NEUTRAL FATS PHOSPHOLIPIDS STEROIDS WAXES TWICE AS MUCH ENERGY PER GRAM THAN CARBOHYDRATES Lipids • ARE THE PRIMARY COMPONENTS OF CELL MEMBRANES. • CONSIST OF C, H, AND O. • ARE NONPOLAR AND INSOLUBLE IN WATER. NEUTRAL FATS • Called fats or triglycerides contain glycerol and fatty acids; formed by dehydration synthesis. Figure 2.9c SATURATED VS UNSATURATED FATS TYPES OF NEUTRAL FATS • MONOGLYCERIDE • DIGLYCERIDE • TRIGLYCERIDE – COMMON STORAGE MOLECULE PHOSPHOLIPIDS • Contain C, H, and O + P, N, or S. • Membranes are made of phospholipids Figure 2.10a Steroids • Consist of four carbon rings, with an –OH group attached to one ring. • Are part of membranes. Figure 2.11 PROTEINS • ARE ESSENTIAL IN CELL STRUCTURE AND FUNCTION. • ENZYMES ARE PROTEINS THAT SPEED CHEMICAL REACTIONS. • TRANSPORTER PROTEINS MOVE CHEMICALS ACROSS MEMBRANES. • FLAGELLA ARE MADE OF PROTEINS. • SOME BACTERIAL TOXINS ARE PROTEINS. Proteins • Consist of subunits called amino acids. Table 2.4.1 Proteins Table 2.4.2 AMINO ACID STRUCTURE • AMINE GROUP • CARBOXYL • REMAINDER OF THE MOLECULE Amino Acids • Exist in either of two stereoisomers, D or L. • L-forms are most often found in nature. Figure 2.13 PEPTIDE BONDING • COVALENT • DIPEPTIDES • POLYPEPTIDES Peptide Bonds • Peptide bonds between amino acids are formed by dehydration synthesis. Figure 2.14 PEPTIDE BONDS • Peptide bonds between amino acids are broken by hydrolysis. PROTEIN STRUCTURE • • • • PRIMARY SECONDARY TERTIARY QUATRENARY PRIMARY STRUCTURE • SEQUENCE OF AMINO ACIDS SECONDARY STRUCTURE • ALPHA HELIX • BETA SHEET TERTIARY STRUCTURE • DETERMINES THE BIOLOGICAL FUNCTION OF THE MOLECULE QUATERNARY STRUCTURE • COMBINES PROTEINS WITH TWO OR MORE SUBUNITS • The tertiary structure occurs when the helix folds irregularly, forming disulfide bonds, hydrogen bonds, and ionic bonds between amino acids in the chain. MODIFICATIONS OF PROTEINS • Conjugated proteins consist of amino acids and other organic molecules: • Glycoproteins • Nucleoproteins • Lipoproteins CLASSIFICATION OF PROTEINS BY FUNCTION • • • • • • ENZYMES STRUCTURAL PROTEINS CONTRACTILE PROTEINS HORMONES TRANSPORT PROTEINS DEFENSE PROTEINS ENZMES • MOST ENZYMES ARE PROTEINS • CATALYSTS FOR CHEMICAL REACTIONS STRUCTURAL PROTEINS • • • • PARTS OF CELLS AND TISSUES COLLAGEN ELASTIN KERATIN CONTRACTILE PROTEINS • ACTIN • MYOSIN HORMONE • INTERCELLULAR MESSENGERS • INSULIN • GROWTH HORMONE TRANSPORT PROTEINS • HEMOGLOBIN& MYOGLOBIN • ALBUMIN DEFENSE PROTEINS • IMMNOGLOBULIN • FIBRINOGEN CLASSIFICATION OF PROTEINS BY SOLUBILITY • • • • • • • GLOBULAR PROTEINS FIBROUS PROTEINS LIPOPROTEINS GLYCOPROTEINS NUCLEOPROTEINS CHROMOPROTEINS METALLOPROTEINS GLOBULAR PROTEINS • POLAR NATURE • MOST NUMEROUS OF PROTEINS – ENZYMES – PLASMA PROTEINS – CELL MEMBRANE PROTEINS FIBROUS PROTEINS • INSOLUBLE • ELONGATE TO FORM STRONG FIBERS • STRUCTURAL AND SUPPORTING FIBERS – ELASTIN, KERATIN, MYOSIN AND FIBRIN CLASSIFICATION BY COMPOSITION • • • • • LIPOPROTEINS GLYCOPROTEINS NUCLEOPROTEINS CHROMOPROTEINS METALLOPROTEINS LIPOPROTEINS • CONTAIN FAT AND OTHER LIPIDS GLYCOPROTEINS • CONTAIN SUGARS NUCLEOPROTEINS • BOUND TO NUCLEIC ACIDS CHROMOPROTEINS • CONTAINS HEME GROUP METALLOPROTEINS • CONTAIN METAL IONS NUCLEIC ACIDS • • • • RNA = RIBONUCLEIC ACID DNA = DEOXIRIBONUCLEIC ACID DOUBLE HELIX RESPONSIBLE FOR PROTEIN SYNTHESIS Nucleic Acids • Consist of nucleotides. • Nucleotides consist of a: • Pentose • Phosphate group • Nitrogen-containing (purine or pyrimidine) base Figure 2.16 DNA • Has deoxyribose • Exists as a double helix • A hydrogen bonds with T • C hydrogen bonds with G Figure 2.16 THE NUCLEOTIDES • PURINES • DOUBLE RING • PYRIMIDINE • SINGLE RING – ADENINE – GUANINE – GUANINE – THYMINE DNA STRUCTURE • LINEAR STRANDS • BONDS BETWEEN SUGARS AND PHOSPHATES • DOUBLE HELIX RNA • Has ribose • Is single-stranded • A hydrogen bonds with U • C hydrogen bonds with G Figure 2.17 TYPES OF RNA • mRNA –CODES FOR PROTEINS • tRNA---CARRIES AMINO ACIDS • Rrna---STRUCTURAL COMPONENT OF RIBOSOMES ATP • Has ribose, adenine, and 3 phosphate groups Figure 2.18 CYCLIC NUCLEOTIDES • NUCLEOTIDE CONVERTED TO CYCLIC FORM – CYCLASES • IMPORTANT IN SECOND MESSENGER SYSTEMS • REGULATING CELL FUNCTION • cAMP & cGMP DINUCLEOTIDES • IMPORTANT FOR METABOLIC PROCESS • NICOTINAMIDE ADENINE DINUCLEOTIDE –NAD+ – ELECTRON AND HYDROGEN DONOR AND ACCEPTOR – OXIDATION AND REDUCTIONS ATP • Is made by dehydration synthesis. • Is broken by hydrolysis to liberate useful energy for the cell.