1. Cell Respiration I. Introduction A. History
1. A. Lavoisier in the 1700’s can make wine without living organisms
2. F. Wohler and J. von Leibig supported this idea, but T. Schwann showed juice would not ferment without yeast.
3. In 1860 L. Pasteur proved ethanol amount proportional to the amount of yeast present

2. 4. In 1897 the E. Buchner brothers steps of glycolysis key to fermentation
5. In the early 1900’s A. Szent-Gyorgyi designed Citric Acid Cycle, failed to show relationship to fermentation
6. H. Krebs in 1938 linked glycolysis to citric Acid Cycle via enzyme CoA Kreb’s Cycle

3. II. Aerobic Respiration
A. Overview (Harvesting energy from energy releasing nutrients in the presence of oxygen.)
Figure 6

4. B. Glycolysis (Splitting glucose in half to liberate some energy.)
1. Where occurs?
a. Cytosol
Figure 4.4A
Figure 4.4B

5. 2. Steps & Players a. Components: i. Investment, & iii. Harvest
ii. Splitting,
Figure 6.7C

6. i. Investment (This costs ATP to prepare the glucose for splitting.)
1. Kinase enzyme attaches a P from ATP to glucose (6C) making glucose-P
Prevents glucose from moving back out of cell
2. Isomerase rearranges glucose-P into fructose-P (6C)
Prepares molecule to add another Phosphate
3. Kinase enzyme attaches another P from second ATP to fructose-P, making P-fructose-P
Generates a balanced molecule with a P at either end.

7. ii. Splitting (Dividing the glucose in half)
1. Aldolase enzyme cuts molecule P-fructose-P into two 3C molecules
G3P and Dihydroxyacetone-P
2. Dehydrogenase enzyme liberates H+ and NAD+ steals the electrons from H+ to form NADH + H+
This happens twice or once for each G3P
3. The hole left by the leaving H is backfilled by Pi (inorganic phosphate from your diet) and forms G1,3P
This step balances the two G3P’s with a P on both ends

8. How many NADH + H+ are formed per glucose?
iii. Harvest (paying back the debt and making some money (energy or ATP))
1. Dehydrogenase liberates H+ to NADH + H+
2. Kinase enzyme directly transfers a P from G3P to ADP to make ATP by substrate level phosphorylation (SLP)
How many times does this happen to make how many ATP’s?
3. Mutase enzyme rearranges G3P into G2P
Prepares molecule for more harvest
4. Enolase enzyme rearranges G2P into PEP
Prepares molecule for more harvest
5. Kinase enzyme directly transfers a P from PEP to ADP to make ATP by SLP
Makes pyruvate out of each PEP
How many NADH + H+ are formed per glucose?

9. 3. Outcomes (Where do the products go?)
a. 2ATP are used by the cell.
The next two outcomes only happen if oxygen is present in the cell.
b. NADH + H+  mitochondria and electron transport chain
c. 2pyruvic acids are combined to CoA to go to the mitochondria and the Kreb’s cycle

10. C. Transport to Kreb’s cycle (a taxi ride to the mitochondria)
1. Where occurs?
a. Cytoplasm to Mitochondria
2. Steps & Players
Figure 6.8
a. Dehydrogenase enzymes splits off a CO2 from pyruvic acid which liberates electrons from H+ and given to NAD+ to make NADH +H+ and a 2C acetyl group
b. Combine acetyl group to Co-enzyme A to be transported to the mitochondria
How many times this happen?

11. 3. Outcomes (Where do the products go?)
The next two outcomes only happen if oxygen is present in the cell.
a. NADH + H+  mitochondria and electron transport chain
b. 2pyruvic acids combined to 2CoA go to the mitochondria and the Kreb’s cycle
c. CO2 is expelled

12. D. Krebs Cycle (A process to destroy the remains of the original glucose)
1. Where occurs?
a. mitochondrial matrix
Figure 4.13

13. 2. Steps & Players a. Divisions i. Destroying ii. Rearranging
Figure 6.9B

14. i. Destroying (tearing apart the remains of the glucose)
1. Enzyme Citrate synthase combines acetic group to oxaloacetic acid to begin cycle
2. Dehydrogenase enzymes splits out CO2 and liberates H+ to NAD+
How many CO2 are liberated?
3. As H+’s are removed then a Pi (inorganic phosphate from your diet) jumps on only to be removed to form ATP by SLP
ii. Rearranging (rebuilding our starting molecule of oxaloacetic acid)
1. Mutase and dehydrogenase enzymes reshape molecule to liberate more H’s to rebuild oxaloacetic acid
2. Liberates H+ and NAD+ or FAD steals the electrons
This happens twice or once for each acetic group

15. 3. Outcomes (Where do the products go?)
a. ATP used
b. CO2 diffuses into cytosol and lost
c. NADH + H+ and FADH2 to electron transport chain

16. E. Electron Transport Chain (Passing hydrogen’s electrons between friends)
1. Where occurs?
a. Inner Mitochondrial Membrane
Figure 4.13

17. 2. Steps & Players a. Divisions i. Build-up & (making the gradient)
ii. Harvest (dissipating the gradient to make ATP)
Figure 6.10

18. i. Build Up (establishing a hydrogen gradient)
1. NADH + H+ and FADH2 drop the electrons from H+ to a series of re-dox proteins called cytochromes
2. As electrons move down the chain they lose energy which is used to move the H+ proton across the membrane to establish potential energy
ii. Harvest (releasing a hydrogen gradient)
1. The electrons are eventually passed to an awaiting Oxygen atom
2. The H+ proton moves back across the membrane through ATP Synthase and to the waiting O2 to form water
3. Conversion of energy (Potential to Kinetic) is used to form ATP

19. 3. Outcomes (Where do the products go?)
a. ATP used
b. NAD+ and FAD+ sent back (to where?)
c. Water moved out or used

20. F. Summary of Aerobic Respiration
Figure 6.12

21. III. Anaerobic Respiration (or what to do if O2 is not available)
A. Fermentation
1. Who?
2. Process
only glycolysis
Figure 6.13A

22. A. Lactic Acid Shuttle 1. Who? 2. Process
Animal cells == lactic acid shuttle and Liver
Figure 6.13B

23. IV. Versatility
A. Routes
B. Problems
Figure 6.15

24. V. Regulation
A. Mechanisms
B. Sites
Figure 6.16