1. The Process of Cellular Respiration

2. Learning Objectives Describe what happens during glycolysis.
Describe what happens during the Krebs cycle.
Explain how high-energy electrons are used by the electron transport chain.
Identify how much ATP cellular respiration generates.

3. Photosynthesis and Cellular Respiration
Photosynthesis and cellular respiration can be thought of as opposite processes.
Why??
What do you think
Goes in and comes out?
Where in the cell do you
Think cellular respiration takes place?

4. Cellular Respiration The chemical summary of cellular respiration is:
What does the equation look like expressed in symbols?

5. Energy Review Energy Storing Molecules:
ATP, NADPH (NAD+), FADH (FAD+), FADH2
ATP supplies most of the energy that drives metabolism in living things
ATP releases energy when converted into ADP

6. Cellular Respiration Overview Chapter 9
Living things get most of the energy they need from glucose.
Autotrophs make glucose using photosynthesis
Heterotrophs get glucose from food they eat
Cellular Respiration
The process that releases energy by breaking down glucose and other food molecules in the presence of oxygen.

7. Electron Transport Chain
Figure 9–2  Cellular Respiration: An Overview
Mitochondrion
Electrons carried in NADH
Electrons carried in NADH and FADH2
Pyruvic acid
Glucose
Electron Transport Chain
Krebs Cycle
Glycolysis
Mitochondrion
Cytoplasm

8. 3 Stages of Cellular Respiration
Glycolysis
Krebs cycle
Electron transport
Main source of energy produced=
ATP!!!!

9. Glycolysis Glyco = Glucose lysis = Breakdown
Occurs in the cytoplasm of the cell
One molecule of glucose is converted to two molecules of pyruvic acid.

10. Glycolysis: ATP and NADH Production
Cell must use (invest) 2 ATP
Produces Energy Carrier Molecules
4 ATP
2 NADH
And
2 Pyruvic acid

11. The End Result of Glycolysis
4 ATP molecule used for energy
2 NADH molecules Electron carriers to ETC
2 Pyruvic Acid Krebs Cycle

12. After step 1 After this step there is a fork in the road
If oxygen is present….
If no oxygen….
Lets explore one option today

13. The Krebs Cycle Aerobic Process = Only occurs if oxygen is present!!
Pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions.
Aerobic Process = Only occurs if oxygen is present!!
Occurs in the MATRIX of the mitochondria (the maze)

14. The Krebs Cycle
Pyruvic acid from glycolysis is used to make NADH, ATP, and FADH2, with carbon dioxide as a by-product.
1 ATP
3 NADH
1 FADH2
CO2

15. The Krebs Cycle: Energy Extraction
For each turn of the cycle, a molecule of ADP is converted to a molecule of ATP.

16. The End Result of the Krebs Cycle
1 ATP molecule used for energy
3 NADH molecules Electron carriers to ETC
1 FADH2 molecule Electron carrier
CO2 Byproduct

17. Electron Transport
Products from the Krebs cycle and glycolysis feed into the last step of cellular respiration- NADH and FADH2
Occurs in the folds of the Inner Membrane of the Mitochondria
The electrons are passed down a chain of proteins until they reach the final electron acceptor…..oxygen!
So this step is aerobic (requires oxygen)

18. Electron Transport
Electron transport chain is composed of a series of electron carriers located in the inner membrane of the mitochondrion.

19. Electron Transport
Electron transport uses the high-energy electrons from glycolysis and the Krebs cycle to synthesize ATP from ADP.

20. Total ATP from Cellular Respiration
Glycolysis, the Krebs cycle, and the electron transport chain release about 36 molecules of ATP per molecule of glucose. 2
Total ATP? 2
30 to 42
CO2 32