1. Chapter 9: Cellular Respiration
AP Biology
Mrs. Ramon

2. ATP
ATP Structure
Close packing of the 3 negatively charged P result in an unstable, E storing arrangement
ADP
ATP
Energy
Energy
Adenosine triphosphate (ATP)
Partially
charged
battery
Fully
charged
battery

3. Pathways Fermentation Cellular Respiration Anaerobic respiration
w/o oxygen
Partial degradation of sugar
Cellular Respiration
Aerobic respiration
w/ oxygen
Mitochondria

4. How does the decomposition of glucose lead to E production?
In cellular respiration, glucose and other fuel molecules are oxidized, releasing energy.
C6H12O6 + 6O2  6CO2 + 6H2O
Glucose is oxidized, oxygen is reduced, and electrons loose potential energy.
Molecules that have an abundance of hydrogen are excellent fuels because their bonds are a source of “hilltop” electrons that “fall” closer to oxygen.

5. Oh no! Chemistry again?!? What’s an redox reaction?
Oxidation-reduction or redox reactions
Transfer of e-
Oxidation: loss of e-
Reduction: addition of e-
Example
Na + Cl  Na+ + Cl-

6. What does a redox reaction look like?

7. How does a redox reaction produce E?
E is needed/required to pull an e- away from an atom (uphill)
E is lost/released when an e- shifts away from a less electronegative atom to a more electronegative atom (downhill)

8. Play it again Sam
In cellular respiration, glucose and other fuel molecules are oxidized, releasing energy.
C6H12O6 + 6O2  6CO2 + 6H2O
Glucose is oxidized, oxygen is reduced, and electrons loose potential energy.
Molecules that have an abundance of hydrogen are excellent fuels because their bonds are a source of “hilltop” electrons that “fall” closer to oxygen.

9. Cellular Respiration 3 metabolic stages: Glycolysis The Krebs cycle
ETC and Oxidative phosphorylation

13. In the absence of O2 - Alcoholic Fermentation
Pyruvate is converted to ethanol in two steps:
Pyruvate is converted to a two-carbon compound, acetaldehyde by the removal of CO2.
Acetaldehyde is reduced by NADH to ethanol.

14. In the absence of O2 - Lactic Acid Fermentation
Pyruvate is reduced directly by NADH to form lactate (ionized form of lactic acid).
When O2 is scarce cells will undergo lactic acid fermentation
The waste product, lactate, may cause muscle fatigue, but ultimately it is converted back to pyruvate in the liver.

15. With O2 - Into the mitochondria

16. The Krebs cycle consists of eight steps.

18. ATP Synthase
A protein complex, ATP synthase, in the cristae actually makes ATP from ADP and Pi.
ATP uses the energy of an existing proton gradient to power ATP synthesis.
This proton gradient develops between the intermembrane space and the matrix.

20. Options
Facultative anaerobes can survive using either fermentation or respiration.
Human muscle cells can behave as facultative anaerobes, but nerve cells cannot.
For facultative anaerobes, pyruvate is a fork in the metabolic road that leads to two alternative routes.

21. Other macromolecules also provide E
Carbohydrates, fats, and proteins can all be catabolized through the same pathways.

22. Stop!
Control of catabolism is based mainly on regulating the activity of enzymes at strategic points in the catabolic pathway.
One strategic point occurs in the third step of glycolysis, catalyzed by phosphofructokinase