Energy & Metabolism Chapt. 6Kinetic EnergyPotential EnergyForms of EnergyHeatThermodynamicsEnergy FlowSunlight to Chemical BondsEnergy from Chemical BondsCovalent BondsElectron EnergiesSlide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Red/Ox Reaction: NADH/ NAD+Example of the Energy in Covalent BondsHow do we know this?Slide 26The Second LawSlide 28And so… The Universe is Breaking DownSo What’s This Got to do with Life?Energy from FoodHow to measure the Energy in a molecule?In Chemical Reactions, usually it’s the Change in E. between Reactants and Products that mattersEnergy + Reactants --> ProductsEndergonic ReactionsReactants --> Products + EExergonic ReactionsActivation EnergyCatalysts and EnzymesEnzymesHow Enzymes Work to Speed Up ReactionsFactors Affecting Enzyme ActivityCompetitive InhibitorsNoncompetitive InhibitorsHow do cells use the energy of chemical bonds for work in the cell?ATPEnergy & Metabolism Chapt. 6 •All living things require energy•One of the primary functions of macromolecules is to provide E.•Energy is the ability to do Work•Energy exists in two forms:–Kinetic Energy–Potential EnergyKinetic EnergyKinetic energy is the energy of motion. An object which has motion - whether it be vertical or horizontal motion - has kinetic energy. There are many forms of kinetic energy - vibrational (the energy due to vibrational motion), rotational (the energy due to rotational motion), and translational (the energy due to motion from one location to another). The amount of translational kinetic energy which an object has depends upon two variables: the mass (m) of the object and the speed (v) of the object. Kinetic energy is an expression of the fact that a moving object can do work on anything it hits; Moving objects cause other objects to move…Movement is work •Text pg 96Potential Energy•Stored energy•Objects with the capacity to do work but not active now have PE.•Kid on the top of a slide•Bolder perched on an edge•Chemical bonds…•Much of life relates to converting PE to KE PE= mass x gravity x heightForms of Energy •Mechanical•Sound•Electricity•Light•Radiation •HeatHeat•Useful way to study energy because all other E. forms can be converted to heat•This is the study of Thermodyn amics•Heat Energy measured in units of calories or kilocaloriesThermodynamics•Thermodynamics is a branch of physics which deals with the energy and work of a system…Energy Flow•Ultimately, all E. for life on earth comes from the sun•Sunlight shines 40 million billion calories/second on earth!•Plants, algae and photosynthetic bacteria convert sun E. to sugarsSunlight to Chemical Bonds•Photosynthesis converts a small (~10%) amount of sun E. into covalent bonds•Where does the rest (~90%) of sunlight E. go?Energy from Chemical Bonds•Chemicals may be considered from a potential energy or kinetic energy standpoint. One pound of sugar has a certain potential energy. If that pound of sugar is burned the energy is released all at once. The energy released is kinetic energy (heat). So much energy is released that organisms would burn up if all the energy was released at once.• Organisms must release the energy a little bit at a time.Covalent Bonds•Sharing of electrons between atoms•Covalent bonds are a form of PE•Energy is stored in each covalent bond•Breaking covalent bonds releases E. ~98Kcal/Mole for C-H bonds•Bond energy is the energy in each orbiting e-Electron Energies•In Oxidation/Reduction reactions e- are passed from one atom to another•Oxidized atom gives e- to reduced atom•Reduced form now has more energy than oxidized one•The amount of E passed on by e- depends on how far it was from the nucleus Reduction is the gain of an electron. Sometimes we also have H ions along for the ride, so reduction also becomes the gain of H. Oxidation is the loss of an electron (or hydrogen).Photon of LightRed/Ox Reaction: NADH/ NAD+Example of the Energy in Covalent BondsPhotosynthesis:6CO2 + 12H2O + Light E.  C6H12O6 +6O2 + 6H2OLight Energy requirements = ~3,000-7,000 KcalRespiration:C6H12O6 + 6O2  6CO2 + 6H2O + EnergyEnergy released = 686 Kcal•Photosynthesis uses lots of energy (3000-7000 Kcal) to produce one glucose molecule…•But, the energy released from one glucose molecule produces only 686Kcal •Most of the excess energy is lost as Heat...but the energy is never really gone…Energy Loss in each Energy TransferAll Energy transfers follow certain rules… •First Law… Energy can never be created nor destroyed.•The total amount of Energy in the universe remains always the same, it just changes forms… The Laws of ThermodynamicsHow do we know this?This is an empirical law, which means that we know that energy is conserved because of many repeated experiments by scientists. It's been observed that you can't get any more energy out of a system than you put into it . James Prescott Joule did a famous experiment which demonstrated the conservation of energy and showed that heat and work were both of the same nature: energy. His experiment involved water in a thermally insulated container and a paddle which was connected to the outside world (surroundings). Joule found that the amount of energy could change from one form to another (work to heat); however, no net change of energy in the system plus the surroundings occurred and thus Energy is conserved.http://www.secondlaw.com/two.html•The first law is very simple: You can't create or destroy energy.•You can just change it from one form to another, for example, electricity to heat, heat that will boil water and make steam, hot steam to push a piston (mechanical energy) or turn a turbine that makes electricity which can be changed to light (in a light bulb) or, using only a tiny quantity changed to sound in an audio speaker system, and so forth. The First Law of ThermodynamicsThe Second Law•Energy spontaneously tends to flow only from being concentrated in one place to becoming diffused or dispersed and spread out. •A blowout in a tire and lightning -- what could seem to be more unlike than those! Yet the reason for their occurring is the same, the tendency for concentrated energy not to stay localized, to disperse if it has a chance and isn't hindered somehow.The Second Law•Energy is constantly being converted to random molecular motion (heat Energy) •This random motion is less ordered (disordered) and is always