 Now I marked several of these types of energy as the ones that we're going to pay the closest attention to I Marked light energy and chemical energy, and I'm also going to mark kinetic energy because the kinetic energy of atoms fuels a lot of reactions in living systems a lot of processes in living systems have an energy Because of the kinetic energy of the molecules to start with we already saw that when we talked about transport of molecules in and out of the salmon brain so some rules We definitely Transfer energy from these different kinds so chemical energy becomes kinetic energy I am not just sitting here moving around and doing this lecture because I have chemical energy in me. I actually took that chemical energy and I transferred it to potential. I mean kinetic energy of motion and Those energy transfers are we've got some rules first of all we have a law of conservation of energy and I know we talked about the conservation of matter and in that context we talked about how In chemical reactions you we actually have to balance out a chemical equation Because you can't end up with more matter Then you started with and you can't make matter disappear The matter that you put into a chemical reaction Will show up on the other end of the case like you will have the same number of atoms when you start and when you finish You just have them put together differently. It's like you took a pile of Legos that were Battleships and you rebuilt them into the same used all the same Legos and you built an alien spaceship It's just a reaction and the matter is conserved in Energy exchanges or transformations that energy is conserved. So you can't lose Energy the amount of energy that you start with is the amount of energy you end up with this is a This is a It's an important law, but again like most things it takes a little while to go level How does this even matter and we will play with how this is? Relevant, especially when we start looking at those energy transfers for living systems the conservation of energy means you can't Can't Create or that should be an or Destroy Energy it just Changes Form that little triangle. I use it all the time and it just means it's shorthand for change Conservation of energy states Energy can change form, but it can't be created or destroyed So what you start with is what you end up with however not Maybe we'll say it like this energy Transformations are never 100% efficient Efficient So if they're not a hundred percent efficient what but you can't Create it or destroy it They're not efficient what that means is that if you have a blob of energy you have a blob of potential energy and You take that like you have a ball and you drop the ball So it has a certain amount of potential energy you drop it All of that potential energy should be transferred into kinetic energy and If that were true then the kinetic energy the ball would actually Rise back up to the same height that from which you dropped it because that's how much potential energy it had You transfer it into kinetic energy it bounces off the ground and it it should contain the same amount of Kinetic energy to get back to that same height if The energy transformation was 100% efficient and they're just not so If we have that potential energy and we transfer it or transform it, there's a different word. What's my word that I need? We're changing forms of energy Some energy is always and I say that it is lost But that's a little misleading It's transformed into something not usable which is heat and Even saying heat is not usable is a little misleading because if we didn't produce heat in our bodies like our Processes are not 100% efficient. We don't transition all of our food energy into Kinetic energy of whatever we're doing We produce a significant amount of heat as part of the outcome The total amount of food energy we put in will equal the movement energy plus The heat energy that we produce so the total amount of energy is the same in both places Heat is considered kind of a biological waste But that's mostly because we can't capture heat for the most part to do Additional work we can't we can't run a sodium potassium pump or a Transporter we can't do that. We're flex your muscle. You can't Contract your muscle using heat energy. You need a more refined form of energy in order to pull that work off So so our rules of energy are that you can't create it or destroy it You can only change forms, but when you do change forms those Changes are never 100% efficient This is going to be relevant to us when we look at chemical energy in this stored Potential energy in chemical bonds, so we're going to spend a whole little section talking just about chemical energy