Biology - Respiration Notes

BIOLOGY - RESPIRATION QUICK NOTES Glycolysis takes place in the cytoplasm: Glucose is activated by 2ATP - substrate-level phosphorylation → splits into two molecules of TP TP is oxidised to form pyruvate, producing ATP and reduced NAD. Link reaction: pyruvate is oxidised, → NADH produced loses a molecule of CO2 combines with coenzyme A to produce Acetyl coenzyme A Krebs cycle: (matrix) acetyl coA + 4-C molecule becomes a 6-C molecule the 6-C molecule loses 2 molecules of CO2, produces reduced coenzymes FAD and NAD and produces one molecule of ATP this regenerates the 4-C molecule, which accepts another molecule of acetyl coA Electron-transport chain: FAD and NAD donate electrons to first molecule in electron transport chain Protons released in matrix Protons are actively transported across membrane using energy from electron-transfer H+ ions move passively down their electrochemical concentration gradient through ATP synthetase, producing ATP via oxidative phosphorylation. Oxygen accepts H+ ions and electrons, forming water (is final electron acceptor) Cyanide: non-competitive inhibitor of final enzyme in electron transport chain oxygen cannot accept electrons electron transport chain stops – build of of H+ ions, reduced NAD and FAD no ATP can be produced cell dies Anaerobic respiration: Glycolysis followed by: production of ethanol +CO2 + NAD from pyruvate + NADH – plants/yeast production of lactate and NAD from NADH – animals Lactate build up lowers pH, causing enzymes to work more slowly. This slows respiration (both anaerobic and aerobic), concequently causing muscle cramp and fatigue.

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