1. Cellular Respiration Review
Occurs in all eukaryotes
Generates ATP
Involves oxidation – reduction reactions
Oxidation = loss of electron / H atom; Reduction = gain of electron / H atom;
C6H12O O2 6 CO2+ 6 H2O + ATP

2. Glycolosis Takes place in cytoplasm Starts with glucose
NET YIELD: 2 NADH (goes to ETC) and 2 ATP

3. The Prepatory Step & the Krebs Cycle
Takes place in mitochondrial matrix
Uses Coenzyme A to prepare pyruvate
Completes breakdown of glucose to CO2
Each molecule of pyruvate processed generates
4 NADH
1 FADH2
1 ATP

4. Electron Transfer Chain
ETC: Occurs across inner mitochondrial membrane
Electrons from NADH and FADH2 move down ETC
O2 is the final oxygen acceptor
Generates a H+ gradient

5. Electron Transfer Chain
H+ gradient powers ATP Synthase enzyme to phosphorylate ADP to ATP (Chemiosmosis)
ADP + P  ATP
ETC Yield = ATP molecules

6. From O2 (final e- acceptor)
36-ish ATP
2 from glycolysis
2 from TCA (2 rounds)
32 from ETC / OxPhos
So far…
0 FADH2
Used up during ETC
0 NADH
Glucose
6 H2O
From O2 (final e- acceptor)
6 CO2
From C6H12O2

7. What if there’s no Oxygen?
O2 can’t act as final electron acceptor
ETC can’t happen
Can still get 2 ATP from and 2 NADH glycolysis (doesn’t require O2)

8. What if there’s no Oxygen?
PRESENCE OF O2
NADH goes to ETC
ABSENCE OF O2
ETC can’t function
NADH must be oxidized back to NAD+

9. Anaerobic Respiration
Respiration in the absence of oxygen
Oxidizes NADH to replenish NAD+
Lactic Acid Fermentation
Alcohol Fermentation

10. Anaerobic Respiration
LACTIC ACID FERMENTATION
Occurs in muscle cells
Oxidizes NADH to NAD+ by reducing pyruvate to lactate (lactic acid)

11. Anaerobic Respiration
Lactic Acid Fermentation
Alcohol Fermentation

12. Anaerobic Respiration
AlCOHOLIC FERMENTATION
Occurs in yeast
Oxidizes NADH to NAD+ by reducing pyruvate to ethanol (ethyl alcohol)

13. Why we like fermentation
Often used by bacteria to make tasty foods
Used for thousands of years
A method of preserving food

14. Other Organic Molecules as Fuel for Cellular Respiration
Carbohydrates: Enter at beginning of glycolysis
Examples: Starch, Glycogen

15. Other Organic Molecules as Fuel for Cellular Respiration
Fats:
Glycerol  enters glycolysis
Fatty Acids  broken into 2-C pieces and sent to Citric Acid Cycle
1 g fat yields 2x ATP as 1g starch

16. Other Organic Molecules as Fuel for Cellular Respiration
Proteins: broken into amino acids  Can enter respiration at many points

17. Biosynthesis of Molecules
We need to build up molecules as well as break them down
ATP provides the energy f/ biosynthetic reactions
Some are reverse of break-down pathways, some are not