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Lecture 5 Outline (Ch. 9)
I. Respiration Overview
II. Redox Reactions
III. NAD+/NADH
IV. Glycolysis
V. Pyruvate Oxidation
VI. Summary
Cellular Respiration
Overall purpose:
• convert food to energy
• animals AND plants
• complementary to photosynthesis
Cellular Respiration:(Exergonic)
Cellular Respiration
• catabolizes sugars to CO2
• requires O2
• at mitochondrion
Redox Reactions
• as part of chemical reaction, e- are transferred
• e- transfer = basis of REDOX reactions(reduction) (oxidation)
Redox Reactions
• follow the H, e- move with them
Use “H rule” for reactions in this classReactant with more H’s = e donor, will be oxidized
Reactant with more O’s = e acceptor, will be reduced
ZH2 + O2 yields ZO + H2O
Self-Check
Reaction Molecule Reduced
Molecule Oxidized
ZH2 + O2 yields ZO + H2O
CH4 + 2O2 yields CO2 + 2H2O
C6H12O6 + O2 yields CO2 + H2O
C8H18 + O2 yields CO2 + H2O
Oxygen ZH2
• e- moved by NAD/H (from niacin/vit B3)
• NADH carry e- (reduced!)
Where do e- come from?
• NAD+ not carrying e- (oxidized!)
Where do e- go?
• glucose NADH ETC O2 (makes H2O)
Redox Reactions
In this equation NAD+ is converted to NADH.
NAD+ + H+ + 2e- NADH
a. Which is the organic compound reactant?
b. Did this reactant gain or lose electrons to become the product?
c. Is this reactant oxidized or reduced to make the product?
1. glycolysis
• Steps of respiration:
3. Citric acid cycle
4. ETC & oxidative phosphorylation
Steps of Respiration
2. Pyruvate oxidation
4 CO2
2 CO2
1. Glycolysis
• 1 glucose (6C) 2 pyruvate (3C)
• Keep track of: - inputs/outputs
- Electron carriers
plus:
- ATP/ADP
Cellular Respiration
- CO2
- O2
• eukaryotes AND prokaryotes
Fructose-1, 6-bisphosphate
Dihydroxyacetonephosphate
Glyceraldehyde-3-phosphate
4
5
GlycolysisATP
ADP
2
2 ADP
2 ATP
Phosphoenolpyruvate
2 Pyruvate
10
Glycolysis
2 ATP
2 ADP 3 steps not shown
2 NADH
2 NAD+
In glycolysis…..
a. Is any O2 or CO2 used or produced?
b. How many ATP are used? How many are produced? What is the NET ATP production?
c. Where do the phosphates come from to make ATP?
d. What are the outputs of glycolysis and where do these molecules go?
2. Pyruvate Oxidation (coenzyme junction) • 2 pyruvate (3C) 2 Acetyl CoA (2C)
Cellular Respiration
• pyruvate joins coenzyme A (from vitamin B5)
• 2 carbons lost (as CO2)
• 2 NAD+ 2 NADH
Where do the outputs go?