1. How Cells Harvest Chemical Energy – Cellular Respiration

2. Cellular Respiration C6H12O6 + 602  6CO2 + 6H20 Glycolysis
A catabolic pathway
Oxygen is consumed as a reactant along with organic compounds.
Involves three stages:
Glycolysis
Krebs Cycle
Electron Transport Chain

4. What Is ATP? Adenosine Triphosphate Energy used by all Cells
Organic molecule containing high-energy Phosphate bonds

5. Chemical Structure of ATP

6. What Does ATP Do for You?
It supplies YOU with ENERGY!

7. How Do We Get Energy From ATP?
By breaking the high- energy bonds between the last two phosphates in ATP

8. NADH and FADH2
NAD+ traps electrons from glucose to make NADH (energy stored)
Similarly, FAD+ stores energy as FADH2

9. Where Does Cellular Respiration Take Place?
It actually takes place in two parts of the cell:
Glycolysis occurs in the Cytoplasm
Krebs Cycle & ETC Take place in the Mitochondria

10. Review of Mitochondria Structure
Smooth outer Membrane
Folded inner membrane
Folds called Cristae
Space inside cristae called the Matrix

11. Diagram of the Process Occurs in Matrix Occurs across Cristae
Occurs in Cytoplasm

12. Glycolysis 1. Means “splitting of sugar”
2. Occurs in the cytosol of the cell
3. Partially oxidizes glucose (6C) into two pyruvate (3C) molecules.
4. Occurs whether or not oxygen is present.

13. 5. An exergonic process, (meaning energy is released) most of the energy harnessed is conserved in the high-energy electrons of NADH and in the phosphate bonds of ATP

15. Glycolysis Summary Takes place in the Cytoplasm
Anaerobic (Doesn’t Use Oxygen)
Requires input of 2 ATP
Glucose split into two molecules of Pyruvate
Also produces 2 NADH and 4 ATP

16. Formation of Acetyl CoA
1. Junction between glycolysis and Krebs cycle
2. Oxidation of pyruvate to acetyl CoA
3. Pyruvate molecules are translocated from the cytosol into the mitochondrion by a carrier protein in the mitochondrial membrane.
4. A CO2 is removed from pyruvate – making a 2C compound.
5. Coenzyme A is attached to the acetyl group.

17. Formation of Acetyl CoA

18. Formation of Acetyl CoA

19. Krebs Cycle Requires Oxygen (Aerobic)
Cyclical series of oxidation reactions that give off CO2 and produce one ATP per cycle
Turns twice per glucose molecule
Produces two ATP
Takes place in matrix of mitochondria

22. Krebs Cycle Summary
Each turn of the Krebs Cycle also produces 3NADH, 1FADH2, and 2CO2
Therefore, For each Glucose molecule, the Krebs Cycle produces 6NADH, 2FADH2, 4CO2, and 2ATP

24. Electron Transport Chain
1. Located in the inner membrane of the mitochondria.
2. Oxygen pulls the electrons from NADH and FADH2 down the electron transport chain to a lower energy state .
3. Process produces 34 ATP or 90% of the ATP in the body.

25. Electron Transport Chain
4. Requires oxygen, the final electron acceptor.
5. For every FADH2 molecule – 2 ATP’s are produced.
6. For every NADH molecule – 3 ATP’s are produced.
7. Chemiosmosis – the production of ATP using the energy of H+ gradients across membranes to phosphorylate ADP.

26. ATP Synthase A protein in the inner membrane in the mitochondria.
Uses energy of the ion gradient to power ATP synthesis.
For every H+ ion that flows through ATP synthase, one ATP can be formed from ADP

29. Cellular Respiration in Summary
Glycolysis
2 ATP
2 NADH  4-6 ATP (Depends on how this NADH molecule gets to the ETC. To make things simple we will say that these two NADH’s make 4 ATP )
Formation of Acetyl CoA
2 NADH  6 ATP

30. Cellular Respiration in Summary
Krebs Cycle
2 ATP
6 NADH  18 ATP
2 FADH2  4 ATP
Grand Total = 36 ATP

31. Fermentation Occurs when O2 NOT present (anaerobic)
Called Lactic Acid fermentation in muscle cells (makes muscles tired)
Called Alcoholic fermentation in yeast (produces ethanol)
Nets only 2 ATP