Electron transport chain and chemiosmosis

Recap Glycolysis Link Reaction Krebs Cycle Activity – In pairs, without looking at your notes outline the Krebs cycle on the white boards.

Electron transport chain Most ATP is made from glucose catabolism Oxygen is needed Occurs on the inner membrane on mitochondrion and on the membranes of the cristae. Involves electron carriers - cytochromes

Electron transport chain The Electron Transport Chain The hydrogen carriers (NADH + H+ and FADH2) provide electrons to the electron transport chain on the inner mitochondrial membrane As the electrons cycle through the chain they lose energy, which is used to translocate H+ ions to the intermembrane space (creating a gradient) The hydrogen ions return to the matrix through the transmembrane enzyme ATP synthase, producing multiple ATP molecules (via chemiosmosis) Oxygen acts as a final electron acceptor for the electron transport chain, allowing further electrons to enter the chain Oxygen combines the electrons with H+ ions to form water molecules The electron transport chain produces the majority of the ATP molecules produced via aerobic respiration (~32 out of 36 ATP molecules)

Chemiosmosis

Homework Complete notes on oxidative phosphorylation and the electron transport chain Use powerpoint on biologyb.com to support Complete essay question Dues Thursday 16th March

Chemiosmosis Oxidative phosphorylation describes the production of ATP from oxidised hydrogen carriers (as opposed to substrate level phosphorylation) When electrons are donated to the electron transport chain, they lose energy as they are passed between successive carrier molecules This energy is used to translocate H+ ions from the matrix to the intermembrane space against the concentration gradient The build up of H+ ions creates an electrochemical gradient, or proton motive force (PMF) The protons return to the matrix via a transmembrane enzyme called ATP synthase As they return they release energy which is used to produce ATP (from ADP and Pi) This process is called chemiosmosis and occurs in the cristae The H+ ions and electrons are combined with oxygen to form water, allowing the process to be repeated anew

Electron Transport Chain (oxidative phosphorylation) Glycolysis Key Cytoplasm Mitochondrial matrix Inner membrane of mitochondria Pyruvate Acetyl CoA CO2 H2O O2 ATP Reduced NAD Reduced FAD Link Reaction Krebs Cycle Electron Transport Chain (oxidative phosphorylation)

Electron Transport Chain (oxidative phosphorylation) Glycolysis Key Cytoplasm Mitochondrial matrix Inner membrane of mitochondria Pyruvate Acetyl CoA CO2 H2O O2 ATP Reduced NAD Reduced FAD Link Reaction Krebs Cycle Colour code your diagram to show what happens where, and what happens to all the stuff produced in each stage of respiration Electron Transport Chain (oxidative phosphorylation)

Electron Transport Chain (oxidative phosphorylation) Glycolysis Key Cytoplasm Mitochondrial matrix Inner membrane of mitochondria Pyruvate Acetyl CoA CO2 H2O O2 ATP Reduced NAD Reduced FAD Link Reaction Krebs Cycle Electron Transport Chain (oxidative phosphorylation)

Electron Transport Chain (oxidative phosphorylation) Glycolysis Key Cytoplasm Mitochondrial matrix Inner membrane of mitochondria Pyruvate Acetyl CoA CO2 H2O O2 ATP Reduced NAD Reduced FAD Link Reaction Krebs Cycle Electron Transport Chain (oxidative phosphorylation)

Respiration Remix