Biol 1107 Chapter 3 Organic chemistry overviewI. Organic substances are molecules that have C atoms bound to other atoms to form the backbone of the moleculeA. C in organic molecules may be bound to C or to other elements1. Often have long chains of C—C bondsa. Also commonly forms bonds with H, O, N, S, and P2. Very simple C compounds are not considered organica. Ex, CO2, H2CO3B. Properties of C make organic molecules very diverse1. Has 4 e- in its valence shella. Can form 4 covalent bonds to fill its shelli. Contrast to O- Has 6 valence e-- Can only form 2 covalent bonds2. C—C bonds are very stronga. Excellent for forming backbone of long moleculesC—C—C—C—C—C—C…3. Covalent bonds between C atoms can be single, double, or triplea. Share 1, 2, or 3 pairs of e-, respectivelyii. Triple bonds not common in biology4. Covalent bonds between C atoms can be flexible or stiffa. Single bonds can rotatei. Very flexibleii. Good for long moleculesb. Double and triple bonds are stiffi. Cannot rotateii. Can give shapeC. Placement of bonds is very important1. Isomers – molecules with same atoms in different arrangementsa. Same molecular formula, different structural formulasb. Slight structural changes can have large effects in chemical, physical, and biological properties2. Different types of isomersa. Structural isomers – same atoms, different bond partnersi. Ex, C2H6O can be ethanol or dimethyl etherb. Geometric isomers – same atoms, same bond partnersi. Different arrangement of atoms around a central double bondii. Has cis- and trans- forms- Ex, cis- and trans- fatsc. Enantiomers – mirror image isomersi. Only occur when a C has 4 different atoms boundii. Result from 3D shape of carbon compounds D. Functional groups – side groups attached to the backbone of an organic molecule1. Determines behavior of the moleculea. Can make a molecule hydrophobic or hydrophilicb. Can determine physical state of molecule at a given temp. (solid, liquid,or gas)2. Usually written as R—side chaina. R- means remainderi. Shorthand so you don’t have to draw out the whole molecule when only talking about part of itb. Sometimes R- can be backbone, sometimes R- can be side chaini. Just shows that something is attached to atoms of interest3. Important functional groupsa. Polar side chains – make molecules more hydrophilici. R—OH – hydroxyl group. ii. R—COOH – carboxyl group - Weakly acidic- Found in amino acidsiii. R—COR’ – carbonyl group- May be a ketone or aldehydeiv. R—NH2 – amine group- Weakly basic- Found in amino acidsv. R—PO4 – phosphate group- Several may be strung together in high energy bonds- Found in phospholipids, nucleic acids, ATP, etc. b. Nonpolar side chains – make molecules more hydrophobici. R—CH3 – methyl group III. Many important biological molecules are macromoleculesA. Macromolecules are polymers *1. Polymers are large molecules made of repeating smaller subunitsa. Subunits are monomersb. Polymerization is the process of joining monomersi. Involves a condensation reactionii. Enzyme joins monomers by pulling a H2O molecule outc. Reverse reaction is hydrolysisi. Polymer split into monomersii. H2O is consumedd. Different enzymes perform condensation/hydrolysis reactionsi. Avoids futile loops2. Important biological macromoleculesa. Carbohydrates, proteins, nucleic acids, lipidsV. Carbohydrates A. Essential biological molecules1. Includes monosaccharides, disaccharides, oligosaccharides, polysaccharides B. Monosaccharides are simple sugars1. Hexose – monosaccharides with 6 Ca. Glucose (C6H12O6) – very abundant carbohydratei. Important as an energy sourceii. Body closely watches glucose levelsb. Fructose (C6H12O6) – another hexosei. Extremely sweet tasting – found in fruit and honey- high fructose corn syrupc. Galactose (C6H12O6) – yet another hexosei. Found in dairy products2. Pentose – monosaccharides with 5 Ca. Ribose – sugar in RNAd. Deoxyribose – sugar in DNA3. Hexoses and pentoses form rings in solutiona. Linear when dryb. Rings in waterC. Disaccharides are two monosaccharides joined1. May be 2 of the same or 2 differenta. Sucrose = glucose + fructoseb. Lactose = glucose + galactose2. Formed by condensation reactions3. Split into monosaccharides during digestion by hydrolysis reactionsD. Polysaccharides – polymers of many monosaccharides1. Generally 40 to several thousand monomers longa. May be branched or unbranchedb. Several very important polysaccharides2. Starch – main energy storage molecule in plants a. Polymer of α-glucosei. Amylose – linear polymerii. Amylopectin – branched polymerb. Virtually every organism can hydrolyze starch for energy3. Glycogen – main energy storage compound in animalsa. Sometimes called animal starchb. Polymer of α-glucosei. Highly branchedc. Stored mainly in liver and muscle cellsi .Broken down to glucose when we need more energy4. Cellulose – structural carbohydrate found in plantsa. Most abundant carb on earthb. Forms rigid wall around plant cellsi. Forms long, strong bundles of fiberii. Gives them shapec. Polymer of β-glucosed. Cannot be digested by any animali. Ruminants have bacteria in their gut that do itii. Attempts to do this for biofuel purposes5. Other important carbohydratesa. N-acetyl-glucosamine – modified carbohydrate in chitini. Main component of insect and arthropod shellsb. Glucosamine – glucose with a R—OH  R—NH2 changei. Precursor for joint cartilagec. Glycoproteins – proteins with carbohydrate modificationsi. Very large, diverse familyii. Main component of mucusd. Glycolipids – lipids with carbohydrate modificationsi. Common parts of plasma membraneVI. Lipids – fats or fat-like substancesA. Composed mainly of C and H1. Typically very hydrophobica. Important for their function in membranes2. Contain >2x the energy of similar amount of carbs or proteinsa. Makes them efficient for long term energy storageB. Glycerides are the most abundant1. Made of a glycerol backbone and 1-3 fatty acid chainsa. Fatty acids are long, unbranched hydrocarbon chains2. Fatty acids are joined to glycerol via condensation reactionsa. Occurs stepwise b. Monoglycerides have 1 fatty acidc. Diglycerides have 2 fatty acidsd. Triglycerides have 3 fatty acidsi. These are the most common glyceridesii. Main component of vegetable oil and animal fat3. Saturation of glycerides – measure of how many double bonds are present in fatty acid chainsa. Saturated – no