This was a video i found while doing CAPE biology. My teacher Mr.Martin (who for dome strange reason have always reminded me of Dr.House) presented this to the class. The basics of this 2 part video has stuck with me since.
Introduction:
The speaker begins by defining what is an electron chain? By the name of it, obviosly is a mechanism by which electrons are transported from one region to another. This statement however is misleading since OVERALLY its not the same electron moving from point A to point B.
- The Electron transport chain (ETC) is made up of protein complexes which are embedded within the mitochondrial membrane, specifically the highly folded inner membrane.
- Electrons are thansferred across it together with H+ pumping
- Pumping of H+ creates a concentration gradient which is utilized by ATP synthase
The complexes which make up the ETC are:
- NADH Dehydrogenase
- Cytochrome complex
- Cytochrome Oxidase
- ATP Synthase
Yhere are two carries located in the ETC, one located between NADH Dehydrogenase and Cytochrome and another between Cytochrome and Cytochrome Oxidase.
Key substances to the system being:
- NADH + electrons
- Hydrogen ions
- Oxygen molecule
- Water
- ADP +Pi -> ATP
The Process:
The mechanism as illustrated by the video beigins where 2 electrons from NADH enter NADH Dehydrogenase, together a Hydrogen ion for EACH electron which goes on to enter the intermembrane space. These 2 electrons are then carried to the second complex by the first carrier, “Ubiquinone” . These electrons are then passed on to the third complex, Cytochrome Oxidase, with 2 more H+ ions being transferred.
Within the Cytochrome Oxidase complex, a mechanism which requires a total of 4 electrons, a molecule of oxygen and eight hydrogen ions, where they react with each other to give H20, and pumping the other 4 hydrogen across the membrane and into the intermembrane space.
In total, 8 Hydrogen ions have been pumped across the membrane. This has created a gradient, the potential energy within it is used by ATP synthase to form ATP, by use of the starting material ADP + Pi. One hydrogeb ion now moves from higher concentration to lower, by passage through ATP synthase as well as another hydrogen ion which moves from the matrix space. This movement of the Hydrogen ions causes a shift in the ATP synthase resulting in the bonding of 1ADP + 1Pi.. 3 H+ ions are required to move from the membrane to form 1ATP molecule, as this is occurring the concentration gradient is gradually decreasing and eventually there will be no more energy to produce ATP. *THIS ONLY HAPPENS IN THE VIDEO, in live systems the gradient is always maintained since there would be complexes performing the reaction simultaneously*
The Good:
- Animations made it interesting to watch
- Processes were explained in a simple manner and was easy to follow
- Video was short! 🙂
The Bad:
- I know of a reaction somewhere in thy chain where Succinate goes to Fumarate
- Failure to mention the basic that the membrane is impermeable to H+ ions
- One must note that the conversion of NADH + H -> NAD+ does occur at the first complex
biochemnewb 