1. SUMMARY Photoassimilates are oxidized = Energy
The value of RQ ~ oxidation state
Starch => storage glucose=> Resp.
Glycolysis => A net gain 2 or 3 ATP
Hydrolytic = 4 ATP - 2 ATP
Phosphorolytic = 4 ATP - 1 ATP
Oxidative pentose phosphate ~ alternate pathway

2. The Oxidative Pentose Phosphate Pathway
From Glycolysis
Glucose P
NADP +
NADPH
6 - Phosphogluconate
NADP +
CO 2
NADPH
Ribulose P
Xylulose -5-P
Ribose P
To Glycolysis
Sedoheptulose -7-P
Glyceraldehyde- 3 - P
Fructose P
Erythrose-4-P
Erythrose-4-P
Erythrose-4-P

3. THE OXIDATIVE PENTOSE PHOSPHATE PATHWAY
Alternate route ~ glucose => cytosol
Tetrose + Pentose + NADPH
The oxidation of glucose-6-P determines the balance Glycolysis - OPPP. Sensitive to the level of NADP +
Second oxidation ( CO2 removed) = ribulose- 5 - P ( e - acceptor NADPH+)
Products => glyceraldehyde P + fructose P ====> Glycolysis

4. THE OXIDATIVE PENTOSE PHOSPHATE PATHWAY Functions
Generate reducing potential in the form of NADPH. It serves as an electron donor and drive biosynthetic reactions in the cytosol.
The production of pentose phosphate, precursor for ribose and deoxyribose => nuclei acids.
Erythrose-4-P precursor biosynthesis of aromatic aminoacids, lignin and flavonoids

5. The Fate of Pyruvate + O2 Acetaldehyde Lactate CO2 + H2O Ethanol
Aerobic
Anaerobic - Fermentation
+ O2
NADH
PYRUVATE
CO2
NAD +
Mitochondrial
Respiration
Acetaldehyde
NADH
Lactate
NAD +
CO2 + H2O
Ethanol

6. OUTLINE 2.3 Mitochondrion: Structure and Organization.
Citric Acid Cycle (CAC)
Electron transport chain
Alternate electron pathways
Gluconeogenesis

7. OXIDATIVE RESPIRATION THE MITOCHONDRION
Outer membrane
0.5 m
Cristae
Inner membrane
2 m

8. The Citric Acid Cycle The oxidation of pyruvate to carbon dioxide
Pyruvic Acid
NAD +
CoA-SH
NADH
CO 2
Acetyl-CoA
Oxaloacetic Acid
Citric Acid 9
Isocitric Acid
Malic Acid 4
Fumaric acid
- Ketoglutaric Acid
7 FADH2
Succinic Acid 5
ATP
Succinyl- CoA

9. Summary Citric Acid Cycle
Eight enzyme-catalyzed steps
Acetyl-CoA + 4-carbon oxaloacetate =>
6-carbon, tricarboxylic citric acid.
Acetyl group degraded => 2CO2
Four oxidations => 3 NADH and FADH2
One molecule ATP
Oxaloacetate is regenerated
=> allows the cycle to continue
hexose sugar => turn twice

10. Oxidation of NADH and FADH2
ATP Synthase CI
CIII
CIV
2H+
4H+
2H+
Intermembrane space
Cyt b UQ
Cyt a Fo
Inner
FMN
Cyt c
Cyt c1
Cyt a3 F1
FAD
1/2 O2 + 2H+
Matrix
ADP+Pi
ATP
NADH + H +
H2O H+
CII

11. Summary Oxidation of NADH and FADH2
Electrons removed from substrate in the CAC are passed to O2 => mitochondrial electron transport chain.
Four multiprotein complexes and mobile carriers
C. four transfers electrons to O2 => H2O
Proton gradient across the membrane is established. It is used to drive ATP synthesis

12. Alternate Electron Pathways in Plants
At least two pathways are unique to plants
External NADPH Dehydrogenase
Skip complex I => only two ATP formed
Rotenone-Insensitive NADH dehydrogenase => only one ATP
Cyanide-resistant respiration
One possible role is thermogenesis.