1. Chapter 9
Cellular Respiration

2. 9-1 Chemical Pathways Chemical Energy & Food
1 gram of sugar (glucose) has 3811 calories of heat energy
calorie: Amount of heat energy needed to raise the temperature of 1g of water 10C
Calorie (kilocalorie) used in food labeling
1000 calories = 1 Calorie
Energy is gradually released from glucose and other food molecules when it is converted into ATP.

3. Overall View of Cellular Respiration
9-1 Chemical Pathways
Overall View of Cellular Respiration
Chemical Formula
C6H12O6 + 6O CO2 + 6H2O + Energy (ATP)

4. 9-1 Chemical Pathways Glycolysis
Beginning process in the conversion of food into ATP.
Occurs the Cytoplasm of the cell
Requires 2 ATP’s of activation energy
Converts glucose one C6H12O6 into two Pyruvic acid molecules
4 high energy electrons are passed to the carrier molecule NAD+ to form NADH
4 molecules of ATP are released

5. To the electron transport chain
Glycolysis
Section 9-1
Glucose
2 Pyruvic acid
To the electron transport chain
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6. 9-1 Chemical Pathways Fermentation
Release of energy from food molecules in the absence of oxygen (Anaerobic Respiration)
2 Fermentation Pathways
Alcoholic Fermentation – Plant cells
Pyruvic Acid + NADH Alcohol + CO2 + NAD+
Lactic Acid Fermentation – Animal cells
Pyruvic Acid + NADH Lactic Acid + NAD+

7. Lactic Acid Fermentation
Section 9-1
Lactic Acid Fermentation
Lactic acid
Glucose
Pyruvic acid
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8. 9-2 Krebs Cycle & the ETC Aerobic Respiration
Chemical pathway taken when Oxygen is present.
Occurs in the Mitochondria
Releases large amount of ATP from the continued breakdown of glucose.

9. 9-2 Krebs Cycle & the ETC The Krebs Cycle
Pyruvic Acid from glycolysis is used to make CO2, NADH, ATP & FADH2
Krebs cycle occurs in the mitochondria.

10. 9-2 Krebs Cycle & the ETC The Krebs Cycle Steps of Krebs Cycle
Citric Acid Production
Pyruvic Acid enters mitochondria – Carbon is removed forming CO2
Electrons are removed when NAD+ is converted into NADH
Coenzyme A joins 2-carbon molecule forming Acetyl- CoA
Acetyl-CoA then adds the 2-carbon acetyl group to a 4- carbon compound forming Citric Acid.

11. 9-2 Krebs Cycle & the ETC The Krebs Cycle Steps of Krebs Cycle
Energy Extraction
Citric Acids is broken down into a 5-carbon compound then a 4-carbon compound.
Along the way 2 CO2 molecules are released
Electrons join NAD+ and FAD to form NADH & FADH2
One molecule of ATP is generated
Energy tally from one Pyruvic Acid molecule
4 NADH
1 FADH2
1 ATP

12. Figure 9–6 The Krebs Cycle
Section 9-2
Citric Acid Production
Mitochondrion
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13. Electron Transport Chain (ETC)
9-2 Krebs Cycle & the ETC
Electron Transport Chain (ETC)
ETC uses high energy electrons from Krebs Cycle (NADH & FADH2) to convert ADP into ATP

14. Electron Transport Chain (ETC)
9-2 Krebs Cycle & the ETC
Electron Transport Chain (ETC)
Steps of ETC
Electron Transport
High energy electrons from NADH & FADH2 are passed along the ETC which is a series of proteins in the inner membrane of the Mitochondria
Oxygen acts as the final electron acceptor getting rid of the waste of cellular respiration (low energy electrons and hydrogen ions) forms H2O

15. Electron Transport Chain (ETC)
9-2 Krebs Cycle & the ETC
Electron Transport Chain (ETC)
Steps of ETC
Hydrogen Ion Movement
As high energy electrons move down the ETC hydrogen ions are pumped into the intermembrane (Active Transport)
Intermembrane becomes positively charged

16. Electron Transport Chain (ETC)
9-2 Krebs Cycle & the ETC
Electron Transport Chain (ETC)
Steps of ETC
ATP Production
As hydrogen ions escape through ATP synthase ADP is convert to ATP
Each pair of electrons can converted 3 ADP into 3 ATP

17. Figure 9–7 Electron Transport Chain
Section 9-2
Electron Transport
Hydrogen Ion Movement
Channel
Mitochondrion
Intermembrane
Space
ATP synthase
Inner
Membrane
Matrix
ATP Production
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18. 9-2 Krebs Cycle & the ETC Total ATP Net Gain 36 ATP Energy Totals
Glycolysis (2 input 4 output)
Krebs Cycle
ETC (2 input 34 output) +32
Total ATP Net Gain

19. 9-2 Krebs Cycle & the ETC Energy & Exercise
Short Term – 90 Seconds or Less
Lactic Acid Fermentation
Long Term
15 – 20 minutes of stored glycogen after that the cells breakdown other sources of energy in the following order
Complex Carbohydrates
Lipids

20. Comparing Photosynthesis to Cellular Respiration
9-2 Krebs Cycle & the ETC
Comparing Photosynthesis to Cellular Respiration
Photosynthesis
6CO2 + 6H2O C6H12O6 + 6O2
Cellular Respiration
C6H12O6 + 6O CO2 + 6H2O + Energy (ATP)
Light
Chlorophyll