Biology 1406 Lecture test 2 (Ch. 4-6) Rated A+

Biology 1406 Lecture test 2 (Ch. 4-6) Rated A+ Metabolism Sum of all chemical activity Catabolic pathway break down molecules anabolic pathway build more complex molecules bioenergetics study of how organisms manage their energy resources Energy The capacity to do work or cause change. Potential Energy Energy by position or state. Examples - Water held back by a dam, chemical energy and electrical energy in a battery. Kinetic Energy Energy in motion or at work. EX: moving water, energy released by breaking a chemical bond or electrical energy released by a light bulb. Free Energy The portion of energy available to do work in a system. First Law of Thermodynamics States that energy is neither created nor destroyed. Energy can be changed from one form to another. This means that living things can not make their own energy; it must be derived from the environment. Second Law of Thermodynamics States that all systems tend toward disorder. Every energy transfer or transformation increases the randomness of the universe. Living systems must use energy from the environment to maintain order. Exergonic Reactions A reaction in which the reactants contain more energy than the products, thus energy is released to the environment by the reaction. Endergonic Reactions A reaction in which the reactants contain less energy than the products, thus energy is absorbed from the environment by the reaction. Factors that influence the rate of a chemical reaction Temp, pressure, concentration, catalyst Catalyst A substance that promotes a chemical reaction. A catalyst does not cause a reaction to occur between molecules that do not have the potential to react. Catalyst are not consumed by the reaction. Catalyst do not take part in the reaction. Catalyst are not modified by the reaction. A catalyst promotes a reaction by attracting reactants to its surface, thus lowering the energy of activation Enzyme An organic catalyst, usually a protein. Enzymes are very substrate specific where inorganic catalyst promote reactions between many different reactants. Cofactor a metal ion required for the function of an enzyme. Coenzyme A non-protein organic molecule that is necessary for the function of an enzyme. Apoenzyme The protein portion of an enzyme/coenzyme or cofactor complex. competitive inhibitors compete for active site non competitive inhibitor binds to the enzyme in a location other than the active site (an allosteric site) and still manages to block substrate binding to the active site by alteration. Factors that influence enzyme action Temp, pH Allosteric site controls enzyme being turned on and off. Induced fit Enzyme will bind to corresponding substrate, wrap around perfectly, stresses the bonds, requires less energy to break bonds. Feedback control of metabolic pathway feedback