BI110 Lecture Notes - Coenzyme Q10, Electron Transport Chain, Beta Barrel
Document Summary
Glycolysis usually said to be divided into two phases, energy input phase (atp invested, consumed) and then the payoff is the second half of the process. Atp moleculesproduced in glycolysis result from substrate-level phosphorylation: enzyme-catalyzed reaction, transfers phosphate group from substrate to adp. Pyruvate can get through phospholipid bilayer through simple diffusion but not fast enough, a transporter facilitates it. Getting across outer mitochondrial membrane is easy, nonselective channel called a porin (beta barrel proteins)lets pyruvate cross easily by diffusion (from cytosol) Pyruvate concentration are not different enough to drive diffusion (concentration gradient) therefore active transport (requires energy) Enzyme complex: 3 enzymes work together to oxidize pyruvate, nad+ reduced to. Carbon dioxide released, remaining is 2-carbob acetyl group which is linked to coa (acetyl-coa) Pyruvate must be transported across 2 membranes: non-selective porin allows diffusion across omm, mpc actively transports pyruvate across imm. Pyruvate oxidation is a 3 step process catalyzed by a large complex called pyruvate.
