Biology 1002B Lecture Notes - Lecture 4: Activation Energy, Reaction Rate, Thermodynamics
Document Summary
Bio 1002b - lecture 4 energy and enzymes. Clamydomonas is open system matter and energy can enter cell. Some energy is lost in entropy (energy spreading out: everything will break down. Entropy of cell remains low: surroundings gain entropy from cell in forms of heat and waste. Entropic processes in cell happen all the time: membranes, mrna, enzymes break down, therefore, living organisms need energy (food) to counter increasing entropy. G = h t s: exergonic reactions (- g) are spontaneous product has less free energy than reactant. Contributions of enthalpy and entropy: ex. fermentation of glucose to ethanol. Decrease in enthalpy, increase in entropy (phase change, number of molecules increases) Spontaneity of reaction is not correlated with reaction rate. Non-photosynthetic organisms consume produced sugars, give off heat. Reactants need to reach high-energy transition state for reaction to proceed: ea (activation energy) = energy required to reach transition state, rate is proportional to number of activated molecules.
