1. Aerobic Respiration Only occur in the presence of oxygen Two stages
Krebs Cycle
Electron Transport Chain
with chemiosmosis
Prokaryotes
Occur in cytosol
Eukaryotes
Occur in mitochondria

2. Aerobic Respiration After glycolysis, pyruvic acids are produced
Pyruvic acid moves inside mitochondria into mitochondrial matrix (space between two membranes)
Pyruvic acid + CoA  Acetyl CoA + CO2

3. The Krebs Cycle Acetyl CoA  CO2 + H + ATP
The H produced reduce NAD+  NADH
Five steps in the Krebs Cycle
Occurs in mitochondrial matrix
Citric Acid is made in Step 1 therefore this is also called the Citric Acid cycle
Net ATP produced is 2 ATP

4. Krebs Cycle - Step 1 Acetyl CoA + oxaloacetic acid  Citric Acid
This step releases CoA back into the mitochondrial matrix for pyruvic acid to be fixed again

5. Krebs Cycle – Step 2 Citric acid releases CO2 and H
Becomes a 5-carbon compound
The H released, reduces the NAD+ to NADH

6. Krebs Cycle – Step 3 Five carbon compound releases another CO2 and H
Becomes a 4 carbon compound
Another NAD+ is reduced to NADH
Produces an ATP

7. Krebs Cycle – Step 4 4 carbon compound releases H atom
This time, FAD is reduced to FADH2
Similar molecule to NAD+

8. Krebs Cycle – Step 5 4 carbon compound releases H atom
Reduces NAD+ to NADH
This reaction regenerates initial oxaloacetic acid

9. Electron Transport Chain
Uses the high-energy e- from the Krebs Cycle to convert ADP to ATP
Total net ATP produced is 34!!
Prokaryotes
Occurs on cell membrane of organism
Eukaryotes
Occurs in the mitochondria
membrane called cristae

10. ETC – Step 1 NADH & FADH2 are used to power this chain of reactions
NADH & FADH2 are oxidized (lose e-) to the electron transport chain
Also donate H atoms
NADH  NAD+
FADH2  FAD+

11. ETC – Step 2 Electrons from NADH & FADH2 are passed down chain
Lose some energy each time passed on

12. ETC – Step 3
Lost energy from e- transferring down the chain pump protons (H+)
This creates high conc. of H+ between inner and outer membranes
Creates a concentration gradient & electrical gradient since H+ are positive

13. ETC – Step 4
Concentration & electrical gradient in membranes produce ATP molecules by chemiosmosis
ATP synthase is protein embedded in membrane that pumps protons out and creates ATP

14. ETC – Step 5 The electrons move to final acceptor down the chain
Oxygen is the final acceptor
Oxygen also accepts protons provided by NADH & FADH2
The protons, electrons, and oxygen all combine to produce H2O

15. Importance of Oxygen
The only way to produce ATP is by the movement of electrons in the ETC
Oxygen is the final acceptor
Without oxygen, the ETC would halt

16. Efficiency of Aerobic Respiration
Glycolysis = 2 ATP
Krebs Cycle = 2 ATP
ETC = 34 ATP
Total = 38 ATP!!

17. Efficiency Equation Depends on conditions of the cell
How ATP are transported
Cellular respiration is 20 times more efficient than glycolysis

18. Summary Cellular respiration Glycolysis Aerobic respiration
Glucose  pyruvic acid + ATP + NADH
Aerobic respiration
Pyruvic acid  CO2 + H2O + ATP

19. Energy & Exercise
Quick energy – Lactic Acid fermentation is used to get quick energy and gives off lactic acid as a by product, thus the muscle pain.
Long-Term Energy – Use cellular respiration to produce energy. Exercising or activities that last for at least 15 to 20 minutes. Best form for weight control.

20. Comparing Photosynthesis & Respiration
Cellular Respiration
Function
Energy Storage
Energy Release
Location
Chloroplasts
Mitochondria
Reactants
CO2 and H2O
C6H12O6 and O2
Products
Equation
6CO2 + 6H2O  C6H12O6 + 6O2
C6H12O6 + 6O2
6CO2 + 6H2O