1. Cellular Respiration Part II: Glycolysis

2. Curriculum Framework f. Cellular respiration in eukaryotes involves a series of coordinated enzyme- catalyzed reactions that harvest free energy from simple carbohydrates. 2

3. Big Energy Events of Respiration – Glycolysis (breaks down glucose into two molecules of pyruvate) – The citric acid cycle (completes the breakdown of glucose) – Oxidative phosphorylation (accounts for most of the ATP synthesis)

4. Electrons carried via NADH Electrons carried via NADH and FADH 2 Citric acid cycle Pyruvate oxidation Acetyl CoA Glycolysis Glucose Pyruvate CYTOSOL MITOCHONDRION ATP Substrate-level phosphorylation Big Energy Events of Respiration

5. Electrons carried via NADH Electrons carried via NADH and FADH 2 Citric acid cycle Pyruvate oxidation Acetyl CoA Glycolysis GlucosePyruvate Oxidative phosphorylation: electron transport and chemiosmosis CYTOSOL MITOCHONDRION ATP Substrate-level phosphorylation Oxidative phosphorylation

6. Mitochondrion Fuel (glucose) Oxygen Water Carbon dioxide ATP

7. Curriculum Framework GLYCOLYSIS 2.F.1 Glycolysis rearranges the bonds in glucose molecules, releasing free energy to form ATP from ADP and inorganic phosphate, and resulting in the production of pyruvate. 7

8. Glycolysis Glycolysis is thought to be one of the oldest metabolic pathways. This energy harvesting process occurs in the cytoplasm of both prokaryotic and eukaryotic cells. 8

9. GlucoseATPMitochondrion

11. 11 Glycolysis

12. Glycolysis harvests chemical energy by oxidizing glucose to pyruvate 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 Glycolysis occurs whether or not O 2 is present

13. Electron carrier (NADH)

14. ATPPyruvic acid

15. Glycolysis Activation energy input Splitting the fructose Harvesting the energy – 2 NADH + H +, 2 ATP – Two pyruvates (pyruvic acid)

16. 16

17. Substrate Product ADP P ATP Enzyme Substrate-Level Phosphorylation

18. Inputs Outputs Glucose Glycolysis 2 Pyruvate  2 ATP  2 NADH

19. Curriculum Framework 2.F.2. Pyruvate is transported from the cytoplasm to the mitochondrion, where further oxidation occurs. 19

20. What happens to the pyruvate?

21. Oxidation of Pyruvate to Acetyl CoA Before the citric acid cycle can begin, pyruvate must be converted to acetyl Coenzyme A (acetyl CoA), which links glycolysis to the citric acid cycle This step is carried out by a multienzyme complex that catalyzes three reactions

22. Pyruvic acid Outer mitochondrial membrane Inner mitochondrial membrane

23. Carbon dioxide

24. Electron carrier (NADH)

25. Acetyl CoA

26. Pyruvate Transport protein CYTOSOL MITOCHONDRION CO 2 Coenzyme A NAD  + H  NADH Acetyl CoA 123

28. Figure 9.6-3 Electrons carried via NADH Electrons carried via NADH and FADH 2 Citric acid cycle Pyruvate oxidation Acetyl CoA Glycolysis GlucosePyruvate Oxidative phosphorylation: electron transport and chemiosmosis CYTOSOL MITOCHONDRION ATP Substrate-level phosphorylation Oxidative phosphorylation

29. Closing thoughts… What process is represented by A? What process is represented by B? C and D are products of A. What could they represent? What process is occurring at B? What does E represent? What is the fate of E? 29

30. Created by: Debra Richards Coordinator of Secondary Science Programs Bryan ISD Bryan, TX