BIOSC 150 1nd Edition Lecture 29Outline of Last Lecture I. Study of EnzymesII. HelpersIII. RegulatorsIV. Reaction RateOutline of Current Lecture 1. Study of EnergyCurrent Lectureo Cells Need Energy!o Potential energy – stored energyo Kinetic energy – energy of motiono First law of thermodynamics – energy is neither created nor destroyed (only transformed from one type to another)o Second law of thermodynamics – the amount of energy available to do work tends to decrease after any transformation o Energy is measured in kilocalories (kcal)o In any energy transformation, some energy becomes unusableo Unusable energy is “lost” in the form of heato Usable energy is free energy (G)o Unusable energy is entropy (S)o The change in free energy tells us if a reaction is thermodynamically favorable or spontaneouso Spontaneity of chemical reactions is determined by changes in potential energy and entropy Spontaneous reactions: Products have lower potential energy than reactants; Products generally have higher entropy than reactantso Exergonic reactions are thermodynamically favorable o Endergonic reactions are not thermodynamically favorableThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o Energetic coupling allows endergonic reactions to happeno ATP hydrolysis is exergonic Energy released from ATP hydrolysis drives endergonic reactionso Building blocks and energy derived from food is used to build cellular
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