Can someone please help me with this. THanks! Copyright The McGraw-Hill Companie
ID: 146897 • Letter: C
Question
Can someone please help me with this. THanks!
Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display Proteins of electron transport chain Energy EnergyEnergy e Energy Electron donor molecule Electron acceptor molecule High Potential energy of electrons Low a. What electron donor brings electrons to this location? b. Where do these electrons come from? As electrons move from protein A to protein B, how is the energy released from electrons used? c. d. What chemical reaction occurs at C? e. Place a H+ on the region of the diagram that has a high concentration of Ht f. Explain what creates this H+ gradient.Explanation / Answer
a. Coenzymes, NADH and FADH2 act as electron donors in the process
b. NADH and FADH2 are produced in glycolysis and kreb's cycle. Glycolysis is the process of breakdown of one glucose molecule into two pyruvate molecule, 2 ATP molecules and 2 NADH molecules.
in krebs cycle, the pyruvate produced in glycolysis then enters the mitochondrial matrix where in CO2 is removed from Pyruvate to form Acetate. Acetate then undergoes series of reactions to form Oxaloacetate and CO2. Each cycle also yields 1 GTP, 3 NADH and 1 FADH molecule.
c. To start with NADH transfers its electron to complex I and in turn is regenerated as NAD. As the electrons move through complex I, energy is released. The second coenzyme FADH2 transfers its electron to Complex II. both complex I and II pass their electrons to electron carrier called Ubiquinone (Q) which is reduced to form QH2 . This reduced form then delivers the electrons to complex III. as electrons move through complex III more H+ ions are pumped out of the matrix into the intermembrane space. This pumping out of electron establishes an electrochemical gradient and as these H+ flow down their gradient back into the matrix they pass through an ATP synthesizing enzyme called ATP synthase, which produces one ATP per 3 H+.
d. From complex III the electrons are transferred to another carrier called Cytochrome C (CytC). Cyt C carries electrons to complex IV where final concentration of H+ ions are pumped across the membrane. Complex IV passes the electrons to final electron acceptor O2. O2 then splits into two oxygen atom and accepts protons from matrix to form H2O. 4 electrons are required to reduce each molecule of O2 and two water molecules are formed in the process.