BCOR 103 1st Edition Lecture 6 Outline of Last Lecture I Introduction to Transport through a Membrane II Facilitators III Pumps IV Channels Outline of Current Lecture I The Mitochondrial Structure II The Electron Transport Chain Current Lecture Mitochondria are organelles in the cell They are the power houses of the cell as they are the place where the cell makes most of its energy The anatomy of a mitochondria consists of an outer membrane an inner membrane and intermembrane space and a mitochondrial matrix The outer membrane of the mitochondria is smooth and tough It has a beta barrel a passive form of transport which is large enough for molecules up to 5000 in molecular weight to pass but macromolecules are unable to pass the outer membrane The space in between the outer membrane and the inner membrane is referred to as the intermembrane space Due to the beta barrels in the outer membrane this inner space is much like the cytoplasm of the cell It also has a high concentration of a protein needed for the electron transport chain The inner membrane has lots of folds called cristae The folds provide more surface area which allows the mitochondria more space to perform more electron transport cycles which produces more energy The inner membrane is not like the outer membrane at all in that it is extremely rough and difficult for any ions to pass including hydrogen This is a place where structure matches function We will see later that hydrogens passing a part of the inner membrane is how energy is produced so making the inner membrane so that hydrogen atoms cannot pass makes sense Lastly the mitochondrial matrix is the most center part of the mitochondria It is a fluid filled space filled with enzymes proteins and ribosomes The electron transport chain is a biological event that occurs in the inner membrane of the mitochondria In one section there are four complexes and two mobile electron carriers that work together to make energy The first complex in the chain is NADH Dehydrogenase When electrons move through this first complex it alters its shape and allows four hydrogen ions to move from the matrix into the inner membrane space This efficient movement of more These 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 than one proton is known as the proton wire The second complex is called Succinate Dehydrogenase Succinate Dehydrogenase is a complex of enzymes that oxidize the succinate to make FADH2 Complex three is called Oxoreductase or Cytochrome bc1 This complex works in tandem with CoQ CoQ is an electron carrier that moves within the inner membrane CoQ receives electrons from Complex One or Two sometimes both it becomes CoQH2 and gets trapped in the binding pocket of Complex Three CoQH2 docks in the binding pocket of Complex Three and its electrons are distributed appropriately Cytochrome Oxidase is Complex Four and it is made up of 13 protein subunits In between Complex Three and Four runs Cytochrome c It moves from side to side on the outside of the inner membrane All in all these complexes and electron carriers work together to move electrons from the matrix to the inner membrane space to set up a concentration gradient that has an electric component When this electrical gradient is set up it put the mitochondria in a good place to make ATP or energy