Chapter 6MATTER AND ENERGYThere are two major categories of energy---Potential energy is energy stored in matter because of its position or location. ---Kinetic energy is the energy of motion. -Always movingThe Laws of Thermodynamics Describe the Properties of Energy Energy transfer by organisms is subject to two laws of thermodynamics---Second Law of Thermodynamics which states that every energy transfer or transformation makes the universe more disordered (i.e., every process increases entropy at the cost of useful energy)PowerPoint PresentationWhy do you get hot when you work out?If every energy transfer loses usable energy, why doesn’t life on the planet simply run out of energy?Slide 10ENERGY FLOW IN CHEMICAL REACTIONS In all chemical reactions you begin with one set of substances, reactants, and end with a different set of substances, products.Thermodynamics determines whether or not a chemical reaction will occur in the cell, and how much energy it will consume or releaseChemical reactions are either exergonic or endergonicSlide 14Slide 15Slide 16Slide 17Slide 18If energy is given off in a reaction, you can assume that:Although exergonic reactions release energy overall, they require some energy to get them started. This “starter energy” is called activation energy.Slide 21Slide 22Slide 23Coupled reactionsSlide 25Slide 26Which homeostatic process helps us maintain a constant body temperature?CONTROLLING THE METABOLISM OF LIVING CELLS ---Metabolism is the total of an organism’s chemical processesThe chemistry of life is organized into metabolic pathways---Catabolic pathways are metabolic pathways which release energy by breaking down complex molecules to simpler compounds.---Anabolic pathways are metabolic pathways which consume energy to build complicated molecules from simpler ones.Enzymes speed up metabolic reactions by lowering energy barriersSlide 33Enzymes are substrate-specificAn enzyme binds to its substrate and catalyzes the conversion of the substrate (reactants) to the product. The enzyme is unchanged by the process.Slide 36Active siteFeverSlide 39Some enzymes require coenzymes to functionRegulating Metabolic Reactions Metabolic pathways are regulated by controlling enzyme activity.Slide 42Allosteric regulationSlide 44Slide 45Slide 46The catalytic ability of enzymes may also be inhibited by competitive inhibitorsSlide 48When a molecule that is not the normal substrate for an enzyme binds to its active site, this results in:Chapter 6Matter and EnergyMATTER AND ENERGYSome basics you should know:---Matter is anything that takes up space and has mass-the physical material of the universe ---Energy is the capacity to do work.There are two major categories of energy1) potential energy2) kinetic energy---Potential energy is energy stored in matter because of its position or location.---Kinetic energy is the energy of motion.-Always moving Potential energy in biological systems can be stored in chemical bondsThe Laws of Thermodynamics Describe the Properties of EnergyEnergy transfer by organisms is subject to two laws of thermodynamics ---First Law of Thermodynamics (law of conservation of energy) which states that energy can be transferred and transformed, but it cannot be created or destroyed (i.e., the energy of the universe is constant).---Second Law of Thermodynamics which states that every energy transfer or transformation makes the universe more disordered (i.e., every process increases entropy at the cost of useful energy)---Entropy is the measure of disorder, randomness.100 unitschemicalenergy(concentrated)gas25 units kinetic energy(motion)75 units heatenergyFig. 6.2Why do you get hot when you work out?•Muscles are broken down and heat up when you workout.•All the chemical energy in food is directly converted to the energy of heat.•As the energy in food is converted to the energy of movement, all the energy is converted to heat.•As the energy in food is converted to the energy of movement, some of the original energy is converted to heat.If every energy transfer loses usable energy, why doesn’t life on the planet simply run out of energy?The planet isn’t a closed system. Energy is constantly flowing in from the sun.A closed system is a system which is completely isolated from its surroundings. In an open system energy can be transferred between the system and the surroundings.ENERGY FLOW IN CHEMICAL REACTIONSIn all chemical reactions you begin with one set of substances, reactants, and end with a different set of substances, products.A + B C + DReactantsProductsThermodynamics determines whether or not a chemical reaction will occur in the cell, and how much energy it will consume or releaseChemical reactions are either exergonic or endergonic---Exergonic reactions are reactions that release energy.---Endergonic reactions are energy-requiring reactions.energyreleasedproductsreactantsExergonic reactionFig. 6.3Burning glucose-exergonic reactionglucose oxygenO O6energyreleasedOHH6waterCO O6carbondioxideFig. 6.5productsenergyusedEndergonic reactionreactantsFig. 6.4glucoseO O6oxygenOHH6waterPhotosynthesis-endergonic reactionenergyCO O6carbondioxideFig. 6.7EXERGONIC REACTIONSENDERGONIC REACTIONSReleases energy Requires energyReaction is energetically downhillReaction is energetically uphillSpontaneous reaction Non-spontaneous reaction (requires an energy source)If energy is given off in a reaction, you can assume that:•It is an endergonic reaction.•It is an exergonic reaction.•Entropy is decreasing.•The laws of thermodynamics have been defied.Although exergonic reactions release energy overall, they require some energy to get them started. This “starter energy” is called activation energy.--- Activation energy is the amount of energy that reactant molecules must absorb to start a reactionBurning glucose (sugar): an exergonic reactionFig. 6.6Photosynthesis: an endergonic reactionhighlowenergycontentofmoleculesprogress of reactionglucoseactivationenergy fromlight capturedby photosynthesisCO2 + H2Onet energycaptured bysynthesizingglucoseCoupled reactions Chemical reactions which release energy can be coupled to chemical reactions which require energy. Exergonic reactions release energy that can be used to power an endergonic reaction.relaxedmusclerelaxedmuscleExergonic reaction:Endergonic reaction:Coupled reaction:20 unitsenergyATPATPcontractedmusclecontractedmuscle100 unitsenergy released80 units energyreleased as
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