Prerequisite knowledge * ATP (Adenosine triphosphate) is the energy storage unit of currency for the cell. * Make ATP by taking energy from food sources (glucose) do this by harvesting energy that is yielded by breaking bonds * Respiration is taking this energy and putting it into a compartment (ATP) STEP ONE: GLYCOLYSIS C6H12O6 → 2CH3COCOOH * Universal to all cells and is non- spontaneous therefore needs enzymes to catalyze to gradually release energy and store it in ATP * Is anaerobic * Occurs in the cytosol (cytoplasm) of the cell * Glucose is broken down into two molecules of pyruvic acid (an investment in energy-2ATP- is needed) 1. Glucose receives a phosphate group from an ATP molecule (which becomes an ADP molecule)
→Glucose 6-Phosphate 2. Isomerase changes shape of glucose to a pentagon
→Fructose 6-Phosphate 3. Molecule gains another phosphate group to try to become symmetrical (so it’s easier to break down) through ATP becoming ADP
→Fructose 1,6-biphosphate 4. 6C molecule splits into two 3C molecules. However not identical b/c O2 must go to either molecule. 5. →Dihydroxyacetone phosphate
→Glyceraldehyde phosphate 6. Hydrogen (an e-) is removed from both molecules (through oxidation) and put onto NAD+ (an e- acceptor) to become NADH. At the same time an inorganic phosphate group (Pi) is added to each molecule
→1,3-biphosphoglycerate X2 7. A phosphate group from both molecules is removed to make ADP, ATP
→3-phosphoglycerate
8. Mutase moves the phosphate group to the Carbon #2 for both molecules
→2-phosphoglycerate
9. Removal of 1 H2O on both molecules
→Phosphoenolpyruvate
10. Another phosphate group from both molecules is removed to make ADP, ATP
→Pyruvate

* After glycolysis, you are left with 2 pyruvate, 2 ATP (net), 2H2O, 2NADH * What happens next depends on whether or not there is O2 Present
STEP TWO: FERMENTATION / PYRUVATE OXIDATION
Fermentation X2 * If O2 is NOT present fermentation will occur. This is not efficient b/c only a couple NAD+ molecules are produced * 2 types: 1. Alcohol/Ethanol fermentation (used by bacteria and some microorganisms) Carbon dioxide NADH NAD+ * Pyruvic acid Acelylaldehyde Ethanol

* Two molecules of pyruvate go through this process (a decarboxylation and a redox reaction) * Regenerating NAD+ to continue glycolysis (does not give energy) * Is not definite because at 13% alcohol, the cell will be poisoned and die * Some organisms need to rely on glycolysis alone for ATP 2. Lactic acid (lactate) fermentation (used by animals) NADH NAD+ * Pyruvic Acid Lactic Acid

* Goes through redox reaction X2 * also regenerate NAD+ for glycolysis * this causes the pH in your body to increase (we experience this as painful cramps) only way to stabilize is to make O2 Present
Pyruvate Oxidation (transition stage) X2 * pyruvate oxidation will occur if O2 is present and will take place in the cytoplasm to end up in the mitochondrial matrix NAD+ NADH

* Pyruvate Acetyl-Coenzyme A CoA CO2

* Pyruvate is decarboxylized so becomes a 2C molecule. It also goes through a redox reaction for which NADH is later used in the E.T.C. * After the transition stage, you are left with 2Acetyl-coA, 2CO2, 2NADH
STEP THREE: THE KREBS/CITRIC ACID CYCLE (X2) * Is the next step in aerobic respiration and therefore takes place in the mitochondrial matrix * Reactants X2 include: Acetly-CoA, H2O, 3NAD+, FAD, GDP,ADP, 2Pi * Products X2 include: 2CO2, 3NADH, FADH2, ATP 1. Acetyl-CoA is added to Oxaloacetate (4C) but CoA is taken off for the moment therefore only the acetyl component is