MCB 3020C Lecture Notes - Lecture 6: Enzyme Catalysis, Activation Energy, Chemical Energy
Document Summary
Microorganisms grouped into energy classes: chemoorganotrophs conserve energy from organic chemicals, chemolithotrophs oxidize inorganic compounds, phototrophs convert light energy into atp. Types of organisms according to carbon sources: heterotrophs obtain carbon from organics, autotrophs obtain carbon from co2. Energy is measured in units of kilojoules (kj) of heat energy. In any chemical reaction, energy is either required or released. Free energy (g): energy released that is available to do work. The change in free energy during a reaction is referred to as standard conditions. Exergonic: reactions with -standard conditions release free energy. Endergonic: reaction with +standard conditions requires energy. To calculate free-energy yield of a reaction, we need to know the free energy of formation. Free energy calculations do not provide information on reaction rates. Activation energy: minimum energy required for molecules to become reactive: a catalyst is usually required to overcome activation energy barrier.
