1. 9.2 The Process of Cellular Respiration

2. THINK ABOUT IT
Food burns! How does a living cell extract the energy stored in food without setting a fire or blowing things up?

3. THINK ABOUT IT
Mitochondria are where Cellular Respiration takes place.
A microscope in which a beam of electrons is transmitted through an ultra thin specimen.
An image is formed from the interaction of electrons transmitted through the specimen.
The image is magnified and focused on an imaging device.

4. Energy Totals for Cellular Respiration
In the presence of oxygen, the complete breakdown of glucose produces 36 ATP molecules.
This represents about 36 percent of the total energy of glucose. The remaining 64 percent is released as heat.

5. Three Stages: Glycolysis Kreb Cycle Electron Transport Chain

6. Glycolysis
Glucose is broken down into 2 molecules of the 3- carbon molecule pyruvic acid.
Pyruvic acid is a reactant in the Krebs cycle.
ATP and NADH are produced as part of the process.

7. ATP Production Glycolysis requires 2 ATP molecules to get started.
4 ATP are produced during the reactions.
The net total from Glycolysis: 2 ATP

8. NADH Production
During glycolysis, the electron carrier NAD+ accepts a pair of high-energy electrons and becomes NADH.

9. NADH Production
NADH carries the high- energy electrons to the electron transport chain, where they can be used to produce more ATP.
2 NADH molecules are produced for every molecule of glucose that enters glycolysis.

10. The Krebs Cycle

11. Step 1: Pyruvic acid to Acetyl-CoA
Pyruvic acid from glycolysis enters the matrix to form Acetyl- CoA.
Matrix, the innermost compartment of the mitochondrion.

12. Step 1: Pyruvic acid to Acetyl-CoA
NAD+ accepts 2 high- energy electrons to form NADH.
One molecule of CO2 is also produced.

13. Step 2: Citric Acid Production
Acetyl-CoA reacts to produce Citric acid.

14. Step 3: Cycling & Energy Extraction
Citric acid goes through several reactions, finally forming a 4-carbon oxaloacetate which begins the cycle again.
Two molecules of CO2 are released.

15. Step 3: Cycling & Energy Extraction
Energy released by the breaking and rearranging of carbon bonds is captured in ATP, NADH, and FADH2.
NADH and FADH2 move to the Electron Transport Chain.
ATP is used to power cell activities.

16. Energy Extraction
Each molecule of glucose results in 2 molecules of pyruvic acid. Each pyruvic acid “turns” through the Kreb Cycle.
For one glucose molecule, 6 CO2, 2 ATP, 8 NADH, and 2 FADH2 molecules are produced.

17. Review Cellular Respiration
Glycolysis, Krebs Cycle, ETC
2 ATP, 2 ATP, 32 ATP
Cytoplasm, mitochondria, mitochondria
With oxygen, aerobic

18. Glycolysis What happens during the process of glycolysis?
During glycolysis, 1 molecule of glucose, a 6- carbon compound, is transformed into 2 molecules of pyruvic acid, a 3-carbon compound.

19. The Advantages of Glycolysis
Glycolysis produces ATP very fast, which is an advantage when the energy demands of the cell suddenly increase.
Glycolysis does not require oxygen, so it can quickly supply energy to cells when oxygen is unavailable.

20. The Krebs Cycle What happens during the Krebs cycle?
During the Krebs cycle, pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions.

21. Electron Transport and ATP Synthesis
How does the electron transport chain use high-energy electrons from glycolysis and the Krebs cycle?
The electron transport chain uses the high- energy electrons from glycolysis and the Krebs cycle to convert ADP into ATP.