1. Oxidative Phosphorylation & Fermentation

2. Summary of Glycolysis, Link and KC

3. Energy Accounting
By the end of Glycolysis, link and Krebs cycle, how many of the original 6 carbons have been converted to CO2?
All of them
How many ATP’s have been made
4 ATP’s
So where is the rest of the energy that was originally in the glucose?
10 NADH’s
2 FADH2

4. So far the ATP’s have been generated via substrate level phosphorylation
Now it’s time for chemiosmosis
Where is the energy
Coming from
for the
active transport?
???

5. What pulls electrons out of the chain?
What happens to the energy that is lost from the electrons?
AHH, the
active
transport!

6. Protein complex of electron carriers
Figure 9.15 H H H
Protein complex of electron carriers H
Cyt c IV Q
III I
ATP synth- ase II
2 H + 1/2O2
H2O
FADH2
FAD
Figure 9.15 Chemiosmosis couples the electron transport chain to ATP synthesis.
NAD
NADH
ADP  P i
ATP
(carrying electrons from food) H 1
Electron transport chain 2
Chemiosmosis
Oxidative phosphorylation

7. EFFECIENCY OF ATP PRODUCTION
FOR EVERY NADH ~ 2.5 ATP’S ARE MADE
FOR EVERY FADH2 ~ 1.5 ATP’S ARE MADE
10 x 2.5 = 25 ATP’s
2 x 1.5 = 3 ATP
28 ATP’s from Oxidative Phosphorylation
4 from Substrate Level Phosphorylation
What is the efficiency if glucose’s ΔG = -686 kcal/mol, and ATP’s ΔG = -7.3 kcal/mol?
233.6/686 x 100 = 34%

8. Oxidative phosphorylation: electron transport and chemiosmosis
Figure 9.16
Electron shuttles span membrane
MITOCHONDRION
2 NADH or
2 FADH2
2 NADH
2 NADH
6 NADH
2 FADH2
Oxidative phosphorylation: electron transport and chemiosmosis
Glycolysis
Pyruvate oxidation
Citric acid cycle
Glucose
2 Pyruvate
2 Acetyl CoA
Figure 9.16 ATP yield per molecule of glucose at each stage of cellular respiration.
 2 ATP
 2 ATP
 about 26 or 28 ATP
About 30 or 32 ATP
Maximum per glucose:
CYTOSOL

9. Oxidizing Agents NAD+ What is the oxidizing agent of glycolysis?
What is the oxidizing agent of the citric acid cycle/Krebs Cycle?
What is the oxidizing agent of the link reaction?
How is NAD+ obtained to run all of these reactions?
Oxidation of NADH and FADH2 via ETC
Without oxygen what happens to the regeneration of these molecules?
NAD+
GLYCOLYSIS LINK, KC
ETC

10. Without O2 mitochondrial reactions shut down
Figure 9.13
NADH 50
2 e
NAD
Without O2 mitochondrial reactions shut down
FADH2
2 e
FAD
Multiprotein complexes I 40
FMN II
FeS
FeS Q
III
Cyt b 30
FeS
Cyt c1 IV
Free energy (G) relative to O2 (kcal/mol)
Cyt c
Cyt a
How can Glycolysis continue without O2?
Cyt a3 20
Figure 9.13 Free-energy change during electron transport. 10
2 e
(originally from NADH or FADH2)
2 H + 1/2 O2
H2O

11. What has more potential/chemical energy pyruvate or lactate ?
Figure 9.17
2 ADP  2 P i
2 ATP
2 ADP  2 P i
2 ATP
Glucose
Glycolysis
Glucose
Glycolysis
2 Pyruvate 2
NAD 
2 NADH
2 CO2 2
NAD 
2 NADH 
2 H 
2 H
2 Pyruvate
Figure 9.17 Fermentation.
2 Ethanol
2 Acetaldehyde
2 Lactate
(a) Alcohol fermentation
(b) Lactic acid fermentation
What has more potential/chemical energy pyruvate or lactate ?

12. Ethanol, lactate, or other products
Figure 9.18
Glucose
Glycolysis
CYTOSOL
Pyruvate
No O2 present: Fermentation
O2 present: Aerobic cellular respiration
MITOCHONDRION
Ethanol, lactate, or other products
Acetyl CoA
Figure 9.18 Pyruvate as a key juncture in catabolism.
Citric acid cycle

13. Oxidative phosphorylation
Figure 9.19
Proteins
Carbohydrates
Fats
Amino acids
Sugars
Glycerol
Fatty acids
Glycolysis
Glucose
Glyceraldehyde 3- P
NH3
Pyruvate
Acetyl CoA
Figure 9.19 The catabolism of various molecules from food.
Citric acid cycle
Oxidative phosphorylation

14. Oxidative phosphorylation
Figure 9.20
Glucose
AMP
Glycolysis
Fructose 6-phosphate
Stimulates 
Phosphofructokinase  
Fructose 1,6-bisphosphate
Inhibits
Inhibits
What would be a good allosteric/competitive inhibitor?
Pyruvate
ATP
Citrate
Acetyl CoA
Figure 9.20 The control of cellular respiration.
Citric acid cycle
Oxidative phosphorylation

15. This graph shows the pH difference across the inner mitochondrial membrane over time in an actively respiring cell. At the time indicated by the vertical arrow, a metabolic poison is added that specifically and completely inhibits all function of mitochondrial ATP synthase. Draw what you would expect to see for the rest of the graphed line.