Kevin Ahern's BB 350 (Metabolic Energy/Carbohydrates) 2014 - #25

1. Contact me at [email protected] / Friend me on Facebook (kevin.g.ahern) 2. Download my free biochemistry book at http://biochem.science.oregonstate.ed... 3. Take my free iTunes U course at https://itunes.apple.com/us/course/bi... 4. Check out my free book for pre-meds at http://biochem.science.oregonstate.ed... 5. Lecturio videos for medical students - https://www.lecturio.com/medical-cour... 6. Course video channel at http://www.youtube.com/user/oharow/vi... 7. Check out all of my free workshops at http://oregonstate.edu/dept/biochem/a... 8. Check out my Metabolic Melodies at http://www.davincipress.com/ 9. My courses can be taken for credit (wherever you live) via OSU's ecampus. For details, see http://ecampus.oregonstate.edu/soc/ec... 10. Course materials at http://oregonstate.edu/instruct/bb350 1. For every oxidation, there must be a reduction. The most common electron carriers are NAD+/NADH, NADP+/NADPH, and FAD/FADH2. In each of these pairs, the first one listed is in the oxidized form. 2. For a given reaction, this might work as follows Ethanol + NAD+ ---- Acetaldehyde + NADH + H+. In this reaction, ethanol has extra electrons and NAD+ doesn't. On the other side, acetaldehyde has lost the electrons and NADH has them. 3. Energy in cells from oxidation is stored in high energy phosphates of ATP. This chemical energy of storage arises from the repulsive nature of the phosphates for each other. 4. The free energy of a reaction (Delta G) is the energy that is available for doing things in cells. By examining the free energy change that occurs in a reaction, one can determine if a reaction is favorable (goes forward) or not favorable (goes backward). Favorable reactions have Delta G values that are negative. Unfavorable reactions have Delta G values that are positive. When the Delta G for a reaction is zero, a reaction is at equilibrium. 5. For a reaction A --- B (I use the symbol --- to indicate a reversible reaction), if the Delta G is negative, the forward reaction (A ---- B) is favored. If the Delta G is positive, the reverse reaction is favored. If the Delta G is zero, there is no net change in A and B. 6. The term "equilibrium" means that the relative amounts of A and B do not change in the reaction. It DOES NOT mean that the amount of A equals the amount of B. 7. The Delta G for the reaction A ---- B can be calculated from Delta G = DeltaGzeroprime + RTln ([B]/[A]). I simplify this to the following form: Delta G = DeltaGzeroprime + RTln ([Products]/[Reactants]) 8. If [Products] is greater than [Reactants], the ln term is POSITIVE. If the opposite is true, the ln term is NEGATIVE. If the [Products] = [Reactants], the ln term is ZERO. 9. DeltaGzero is a constant that has a specific value for each reaction. Highlights Carbohydrates 1. Carbohydrates are sugar-related compounds that are polyhydroxyaldehydes or polyhydroxyketones. The suffix 'ose' is put at the end of a molecular name to indicate it is a carbohydrate. An aldehyde sugar is an aldose. A ketone sugar is a ketose. 2. The prefixes 'tri', 'tetr', 'pent', 'hex', 'hept', and 'oct' are prefixes for monosaccharides with 3,4,5,6,7, or 8 carbons, respectively. A monosaccharide has only one sugar subunit. Glucose and fructose are monosaccharides. Sucrose is a disaccharide. Glycogen, which is a polymer of many subunits of glucose, is a polysaccharide. 3. Asymmetric carbon centers give rise to stereoismers. Stereoisomers that are mirror images of each other are called enantiomers. Stereoisomers that are NOT mirror images of each other are called diastereomers. 4. A Fischer projection is a stick figure representation of a sugar. By convention, the D isomer of a sugar is indicated by a hydroxyl on the right side on the next to the bottom carbon in a Fischer projection. 5. The geometry of covalent bonds of carbon allows 5 and 6 membered rings to readily form in aldoses and ketoses. Ring structures of sugars are commonly drawn in the Haworth format. 6. Formation of a ring by a sugar creates a new asymmetric carbon called an anomeric carbon.