1. Cellular Respiration Part 2 Glycolysis - Pages 93 to 95

2. Overview: Cellular Respiration Cellular Respiration takes place in three steps: ▫Glycolysis – initial breakdown of glucose; very little direct energy production; takes place in cytoplasm ▫Krebs Cycle – finishes the breakdown of glucose; very little direct energy production; takes place in the matrix of the mitochondria ▫Oxidative Phosphorylation – major energy producing process; takes place in the cristea of the mitochondria

3. Fig. 9-6-3 Mitochondri on Substrate-level phosphorylation ATP Cytosol Glucose Pyruvate Glycolysis Electrons carried via NADH Substrate-level phosphorylation ATP Electrons carried via NADH and FADH 2 Oxidative phosphorylation ATP Citric acid cycle Oxidative phosphorylation: electron transport and chemiosmosis

4. Glycolysis Glycolysis (“splitting of sugar”) breaks down glucose into two molecules of pyruvate Glycolysis occurs in the cytoplasm and has two major phases: ▫Energy investment phase ▫Energy payoff phase

5. Fig. 9-8 Energy investment phase Glucos e 2 ADP + 2 P 2 ATP used formed 4 ATP Energy payoff phase 4 ADP + 4 P 2 NAD + + 4 e – + 4 H + 2 NADH 2 Pyruvate Glucose Net 4 ATP formed – 2 ATP used 2 ATP 2 NAD + + 4 e – + 4 H + 2 NADH + 2 H +

6. Glycolysis Takes place in the cytoplasm Believed to be the oldest metabolic process – shared by all organism ATP produced during the process via substrate level phosphorylation

8. Glycolysis – summarized in words 2 molecules of ATP are used to start the process – phosphorylating (energizing) the 6 carbon molecule– unstable 6C Unstable 6 C splits into to 3 C called G3P Oxidation of 2-3C (G3P) and reduction of 2 NAD+ to 2NADH releases enough energy to phosphorylate the 3C molecule Phosphates removed from 2-3C molecules in substrate level phosphorylation to produce 4 ATP; end with pyruvate

9. Glycolysis Summary Reactants ▫Glucose, 2ATP and 2NAD+ Products ▫Pyruvate, 4 ATP, and 2 NADH Net gain of ATP ▫2 ATP Do you need to know all of the intermediates in the process? ▫NO – understand that it occurs in several steps, each step involves different enzymes & results in a different carbon compound