[Music] in respiration which can be aerobic with oxygen or anerobic without oxygen electrons are transferred from electron donors to electron acceptors through a series of radx reactions now remember Ang glycolysis we created 10 molecules of nadh and two molecules of fadh2 and we need to rebalance these so that glycolysis in the citric acid cycle continues as a reminder these reactions in UK carotic cells are occurring within the mitochondria but we're going to look at Pro carots and here these electron carriers that we're going to talk about are embedded into the cytoplasmic membrane of the cell now these electrons as they're being transferred are losing a little bit of energy so the electrons that are transferred here have less energy than these do here that have less energy than these do here so they're losing a little bit of energy as they go down this chain they lose that energy and that energy is then used because remember energy is neither created nor destroyed that energy is used to pump out protons across the membr M braan now as we do so remember from our previous chapter this outer part of the cell so outside of the cell is becoming more electrically positive and also acidic whereas the internal part of our cell is becoming more electrically negative and alkaline so this is the proton motive force that we're generating now proton motive force can be used as we've talked about before to power transport such as iron transport we've talked about how it can be used to power fella rotation and we're going to talk about how it can be used to drive the formation of ATP through this process of chemiosmosis the kind of concept I want you to get here about why this exists as a series of reactions instead of just one reaction is what would happen if it was just one and I liken that to taking the stairs so if we take the stairs in our building and we go from the top floor and we go step by step by step we don't sprain our ankles we don't break our legs we're safe and we're healthy when we reach the bottom no damage has occurred if we were to jump off the top step we might damage something so that's akin to What's Happening Here the energy that's released as we go through these reactions is allowing this small dissipation of energy and energy remember neither created nor destroyed if that's happening near a membrane that usually results in some kind of heat and heat near lipids is never a good idea so these are going to happen in steps and we'll go through each step here in the next few slides