1. Cellular Respiration Ch. 8

2. How we get Energy from Light
Cellular respiration is just a series of steps where energy is transfer between different molecules through a flow of electrons
The ultimate goal is to produce ATP
The initial start of the process is light during photosynthesis
What is the final acceptor of the electrons used to make ATP?
Oxygen
Combines with H+ to make water

3. OIL RIG OIL Oxidized if lose (electrons)
Electron donor
Decrease in positive electric charge
RIG Reduced if gain (electrons)
Electron acceptor
Increase in positive electric charge
What types of reactions have this occur?
Redox reaction
Not all redox have complete exchange of electrons
Figure 8.2
Moving electrons closer or further from the central atom shows change in energy
Carbon partially lost electrons
Oxygen partially gained

4. Steps of Cellular Respiration
C6H12O6+ 6O2+ 32ADP+ 32Pi 6H2O+ 6CO2+ 32 ATP
3 steps:
Glycolysis
Glucose is broken into 2 pyruvate molecules
Pyruvate Oxidation and Citric Acid Cycle
Pyruvate is made into Acetyl-CoA and enters a reaction cycle
Oxidative Phosphorylation
Electron transporter molecules move to the inner mitochondria membrane and generate ATP

5. Glycolysis Glucose+ 2ADP+ 2Pi + 2 NAD+ 2Pyruvate+ 2NADH+ 2H++ 4ATP
10 enzymes are required
Steps 1 and 3 hydrolysis ATP to build instability and power breaking of glucose to G3P (glyceraldehyde-3-phosphate)
Electron carrier NAD+ (nicotinamide adenine dinucleotide) is reduced to NADH
Step 7 dephosphorylates C-1 to make ATP (2x)
Step 9 releases H2O
Step 10 dephosphorylates C-3 producing ATP and Pyruvate (2x)
What produce to respiration do we not see yet?
CO2
Glucose+ 2ADP+ 2Pi + 2 NAD+ 2Pyruvate+ 2NADH+ 2H++ 4ATP

6. Regulation of Glycolysis
What molecule would best regulate glycolysis?
ATP levels
If ATP levels are high, phosphofructokinase in step 3
What else could regulate it?
NADH levels
Why does alcohol make you fat?
Breaking down alcohol boosts NADH levels in liver cells
NADH stops glycolysis so sugars are converted to glycogen
Alcohol enters Citric acid cycle as acetyl-CoA
Prolonged high NADH levels and extra acetyl-CoA create fatty acids which get stored in adipose cells (fat cells)

7. Pyruvate Oxidation
Active transport pulls pyruvate into the mitochondrial matrix
-COO- is removed as CO2
2-C acetyl binds to coenzyme A to make acetyl-CoA; which can enter the citric acid cycle
2 electrons are also passed on to NADH
2Pyruvate+ 2CoA+ 2NAD+ 2acetyl-CoA+ 2NADH+ 2H++ 2CO2

8. Citric Acid Cycle (Krebs Cycle)
1Acetyl-CoA+ 3NAD++ 1FAD+ 1ADP+ 1Pi+ 2H2O
2CO2+ 3NADH+ 1FADH2+ 1ATP+ 3H++ 1CoA
8 reactions in a cycle convert acetyl-CoA into CO2 and recycle the CoA
Steps 1 and 7 need H2O
Steps 3 and 4 release CO2
Steps 3, 4, and 8 release NADH
Step 6 releases FADH2 (flavin adenine dinuclotide)
Cycle runs twice for each glucose used
What can inhibit the cycle?
ATP levels

9. Alternative Energy Sources
Triglycerides (fats) are hydrolyzed into glycerol and then G3P (step 6 in glycolysis)
Triglycerides (fats) are broken into 2-C units and bind with CoA
Fats are great source of energy but take longer to breakdown
Proteins are broken into AA and then change into pyruvate or an intermediate step in the citric acid cycle

10. Oxidative Phosphorylation
Electron Transport Chain
All NADH/FADH2 bring collected electrons/protons to the inner mitochondrial membrane
Protein complexes I-IV use Cytochrome C and Ubiquinone to transfer electrons through the system
The energy released actively pumps H+ outside of the matrix
Concentration gradient powers ATP synthase like water powers a turbine to make ATP

11. The Complexes
Complexes I, III, and IV use cytochrome c and coenzyme Q (ubiquinone) to move electrons
Cytochromes have a Fe2+ to act as the electron acceptor/donor
Complex IV is the irreversible binding site of cyanide and is inhibited by CO too
Complex II contains the enzyme succinate dehydrogenase (step 6 of the Krebs cycle) and uses FADH2
After Complex IV, the electrons are passed on to O with two H+ to produce H2O

12. Chemiosmosis and ATP Synthase
Proton-motive Force electrochemical gradient of protons used to power ATP synthase
H+ fall down gradient through chemiosmosis and cause a conformational change in ATP synthase that forces ADP and Pi to bind together
1 NADH 2.5 ATP
1 FADH21.5 ATP
Total the ATP:
Glycolysis= 2 ATP
Krebs Cycle= 2 ATP
Oxidative Phosphorylation= 28 ATP
Total = 32 ATP

13. Energy Efficiency Some cells only produce 30 ATP
Less efficient electron transporter (FADH) is used in glycolysis
Found in brain tissue and skeletal muscles
What type of tissue use the more efficient 32 ATP system?
Constantly active organs like the heart, liver and kidneys
How do muscles compensate their ATP needs since they have a less efficient system?
Lactic acid Fermentation
ATP 7 kcal/mol
Glucose 686 kcal/mol
How efficient is this whole process?
33% ((7x322)/686)x100
FADH FADH

14. Aerobic and Anaerobic Reactions
Organism can be:
Strict anaerobes can’t survive in oxygen
Strict aerobes can’t survive without oxygen
Facultative aerobes can survive with or without oxygen
What parts of cellular respiration are aerobic/anaerobic?
Aerobic Krebs cycle/Oxidative Phosphorylation
Anaerobic Glycolysis
Anaerobic Organism can still do glycolysis, but what is left at the end?
pyruvate
Breaking down pyruvate after glycolysis creates different kinds of fermentation

15. Fermentation
Alcoholic pyruvate is converted into ethanol (alcohol and fuel) and released from the cell
Also releases CO2; used to make bread/cakes raise
Lactic Acid pyruvate is converted into lactate
Used to flavor yogurt
Energy supply in muscles when oxygen runs low
Why is it dangerous to us?
Builds up in cells and lowers pH (acidic)
Causes muscle crams and soreness after working out
Must be removed from the cells and broken down in the liver

16. Homework Read Ch. 9 and do Ch. 9 vocab Ch. 8 vocab due Tuesday
Ch 8. “Test Your Knowledge” and “Interpret the Data” p.175 for Tuesday
Ch. 7 “Test Your Knowledge” on p and “Design the Experiment” on p. 154 due Tuesday
Test on Ch. 6, 7, and 8 on Wednesday
Lab on photosynthesis on Wednesday
Ch. 9, 10 and 11 still to cover!