1. Cellular Respiration

2. Cellular Respiration
How we are able to get energy from the food we eat
Three stages
Glycolysis
Kreb’s Cycle
Electron transport chain
Remember the peep
Similar to photosynthesis

4. Why do we need to breathe?
Oxygen is required in cellular respiration
Aerobic
Anaerobic

5. Location of Cellular Respiration
Glycolysis occurs in the cytosol
Kreb’s cycle and electron transport chain occurs in the mitochondria.

6. Glycolysis First stage Glucose split apart and phosphorylated
Without oxygen
Glucose split apart and phosphorylated
3C= pyruvic acid
Electron carrier
NAD NADH
2 ATP produced

7. Do not need to know all the steps
Do not need to know all the steps. Uses 2 ATP to phosphorylate sugar derivatives, making it easy to break down the compounds- remember it makes the compounds more stable when you phosphorylate them. Charged molecules are unable to leave the cell.

8. Glycolysis Advantages
Net release of 2 ATP
Very rapid
Good for when cell’s energy demands rapidly increase

9. Kreb’s Cycle Also known as the Citric Acid cycle
Pyruvic acid moves into mitochondria

11. Kreb’s Cycle Output 2 ATP per glucose molecule NADH and FADH2 CO2
Why is it called a cycle?

12. Electron Transport Chain
This is where the electron carriers come into play
Donate electrons to electron transport chain
Final electron acceptor is oxygen
Creates a proton gradient
ATP synthase creates ATP

13. Step III: Oxidative Phosphorylation
2 steps
Electron Transport Chain
Transfer of electrons
Proteins embedded in membrane
Last transfer is to oxygen
No ATP
Chemiosmosis
ATP synthase
Embedded proteins alternate between oxidized and reduced states as they accept and donate electrons. Oxygen is the final acceptor in chain. Very electronegative. After picking up an electron, it also picks up a pair of hydrogen ions, forming water
Notice how FADH2 comes in later on in the chain. Thus, it provides less energy that NADH does. About one third. Electron transport chain does not make ATP directly

15. Electron Transport End Results
~32 ATP!!!!
FAD+ and NAD+
H2O

16. Overall Result of Cellular Respiration
36 ATP (varies)
36% of energy stored in glucose
What happens to the other 64%?

17. Fermentation Happens in the absence of oxygen
NADH passes electrons back to pyruvic acid
Occurs in cytoplasm

18. 2 Main Types
Alcoholic Fermentation
Lactic Acid Fermentation