Summary of the biochemistry notes best solutions

Summary of the biochemistry notes best solutions Basic principles govern energy maniulations in cells - 1) Molecules are degrades or synthesized stepwise in a sries of reactions termed metabolic pathway. 2) ATP is the energy currency of life 3) ATP can be formed by the oxidation of carbon fuels 4) Metabolic pathways are highly regulate Oxidation - loss of electrons, Reducing agent(reductant)-donanates ectrons, oxidized. For every biological oxidation there is a corresponding reduction. Glucose was oxidized and 6O2 is reduced Reduction - gain of electrons, oxidizing agent (oxidant)-accpets electrons is reduced Oxidizing agent (oxidant) - accepts electrons, is reduced reducing agent (reductant) - donates electrons, is oxidized Coenzymes serves as water-soluable electron carriers - NAD, FAD, NADP NAD and NADP - are coenzymes derived from the vitamin niacin (vitamin B3). When NAD or NADP accepts two electrons and 1 proton it is reduced. So they can except the electrons serving as oxidants in metabolic reactions. NADPH and NADH can serve as reductants by donating electrons. NAD and NADP are the coenzymes of many oxidoreductases (the enzymes that catalyze oxidation-reduction reactions) NAD - generally serves as an energy metabolism cofactor for moat dehydrogenases (removing 2 hydrogen atoms from their substrates) NADP - generally serves as a biosynthetic process cofactor for most reductases FAD - -is a coenzyme derived from riboflavin -is involved in oxidation-reduction reactions for many enzymes -FAD catalyzes electron transfers Reduction potential (E) - measures the tendency of a chemical to be reduced by electrons -Higher reduction potentials will have a greater tendency to accept electrons and be reduced (lower reduction will be oxidized) -more positive reduction potential will tend to take electrons away, thus being reduced(better oxidant); one with the lower reduction potential (more negative) will be oxidized(stronger reductant) Catabolism - larger to smaller catabolic processes -oxidative (reductant) in nature and energy-releasing (exothermic, delta G <0) Anabolism - large molecules from smaller ones (for example making proteins from amino acids) small molecules to larger ones -reductive in nature (oxidant) and require energy input (endergonic delta G>0) Metabolic pathways - 1. Catabolic pathways combust carbon fuels to synthesize ATP Energy derived from fuels or light is converted into adenosine triphosphate(ATP), the cellular energy currency Oxidative energy-releasing 2. Anabolic pathways use ATP and reducing power to synthesize larger biomolecules Reductive energy requiring Catabolism - oxidative-energy releasing Polysaccharides-glucose and other sugarssmaller molecules-to anabolism Anabolism - Nutrients and products of catabolism-requires reducing agents and energy products of anabolism including proteins, nucleic acids, and fats. and carbohydrates-to catabolism ATP - formation of nucleoside triphosphates, like ATP, is essential to meeting the cell's energy need for synthesis, motion, and signaling -Energy in ATP is released by hydrolysis of a phosphate from the molecule -3 phosphate starting with the one closest to the sugar are refers to alpha, beta, gamma, -It is the gamma phosphate that is cleaved in hydrolysis and the product is ADP -in a few reactions, the bond between the alpha and beta is cleaved. When this happens a pyrophosphate (beta linked to gamma) is released and AMP is produced -this latter reaction to produce AMP releases more energy than the first reaction which produces ADP Nucleoside triphophates - -ATP is the best-known and abundant -GTP is also an important energy source (energy source for protein synthesis) -CTP is involved in the synthesis of glycerophospholipids -UTP is used for the synthesis of glycogen and other sugar compounds -the energy is in the form of potential chemical energy stored in the multi-phosphate bonds -Hydrolyzing these bonds releases the energy in them Primary mechanism - -nonphotosynthetic organisms to obtain energy oxidation and carbon is the most commonly oxidized energy source -the energy released during the oxidative steps is "captured" in ATP and can be used later for energy coupling - the more reduced a carbon atom is, the more energy can be realized from oxidation -Fatty acids are highly reduced, whereas carbohydrates are moderately so. Complete oxidation of both leads to carbon dioxide, which has the lowest energy state Oxdation states of carbon - - the more reduced a carbon atom is, the more free energy is released upon oxidation. The most reduced-more hydrogens-more energy most oxidized-least hydrogens-least energy Reduction of fatty acids and carbohydrates - the number of carbons and oxygens palmitic acid if fully oxidized it is because of this that we use fat (contains fatty acids) as our prmary energy storage material free energy change (delta G) - is the amount of free energy released (negative delta G) or absorbed (positive delta G) in a reaction Delta G>0 - the reaction from left to right is energetically unfavorable (endergonic, or energy-consuming) -An input of free energy is required to drive such a reaction -it can occur in cells. 1) couple the reaction with an exergonic reaction, most commonly this is the hydrolysis of a high-energy phosphate bond in ATP 2) Manipulate the concentration of reactants and products by decreasing the concentration of products and increasing the concentration of reactants, a positive(delta G) can become a negative delta G. delta G=O - equilibrium delta G<0 - the reaction from left to reight is energetically favorable (exergonic, or energy-releasing) Thermodynamically unfavorable reaction - a thermodynamically unfavorable reaction in a pathway can be made to occur by coupling it to move a favorable reaction. -unfavorable reactions can be made possible by chemically coupling a highly favorable reaction to the unfavorable reaction