1. Aerobic Cellular Respiration
Section 7.3
Aerobic Cellular Respiration

2. Goals of today’s lesson
By the end of today’s lesson you should be able to:
Know the structure of the mitochondria, and where certain events take place
Know the steps of Pyruvate oxidation.
Know the steps of the Krebs Cycle
Understand how this cycle contributes to ATP production
Know how the ETC and chemiosmosis contribute to ATP production.

3. Mitochondria
Organelle that drives the process of cellular respiration.
The mitochondria are made up of:
Mitochondrial matrix
Double membrane
Inner membrane
Outer membrane
Intermembrane space

4. Mitochondrion
The outer membrane serves the same purpose as any other membrane.
The inner membrane is highly folded that allows many functions of CR to happen.

5. Mitochondria
The mitochondrial matrix is the protein filled fluid that fills the innermost space of the mitochondria.
The intermembrane space is the area between the inner and outer membrane

6. Stage 2: Pyruvate Oxidation
The stage begins with the 2 pyruvate from glycolysis flowing through the membranes into the matrix of the mitochondria

7. Stage 2: Pyruvate Oxidation
1. A CO2 is removed from the pyruvate and released as a waste product (breath out)
2. The remaining two molecules are oxidized by NAD+.
Each NAD+ gains 2 H+ ions and 2 e-
This makes the pyruvate now acetic acid (vinegar) and has moved high energy H+ ions to NAD+

8. Stage 2: Pyruvate Oxidation
3. A compound called Coenzyme A (CoA) attaches to the acetic acid group.
This forms a new compound called acetyl CoA.
The acetyl CoA then moves to the Krebs cycle (stage 3)

9. Stage 2: Pyruvate Oxidation
Products:
Two Acetyl CoA
Two CO2
Two NADH
Yield 6 ATP

10. Stage 3: The Krebs Cycle AKA Citric Acid Cycle:
A cyclic series of reactions that transfers energy from organic molecules to ATP, NADH, and FADH2 while removing CO2
This cycle is an 8 – step process that involves enzymes at each step.

11. Stage 3: The Krebs Cycle
Keep in mind that there were 2 pyruvate molecules brought into pyruvate oxidation so everything that happens in Krebs happens twice.
This takes place in the mitochondrial matrix

12. Stage 3: The Krebs Cycle
As Acetyl CoA enters the cycle the CoA is released and can be used for the next pyruvate
During one complete cycle a total of three NAD+s and one FAD are reduced to form NADHs and FADH2
During one complete cycle an ADP and a P are combined to form one ATP
During one complete cycle two CO2 molecules are produced

13. Stage 3: Krebs Cycle
Acetyl CoA (2 carbons) is brought into the cycle and combines with Oxaloacetatic acid (OAA is a 4 carbon molecule) to make citric acid (6 carbon).
Citric Acid reacts with NAD+ to make NADH with the help of an enzyme and 1 CO2 is removed (5 carbons)
This makes ketoglutaric acid (KGA 5 carbons)
KGA reacts again with NAD+ to make NADH with the help of an enzyme and 1 CO2 is removed (4 carbons), this then reacts quickly with ADP + Pi to make ATP
The reaction with ADP to make ATP creates succinic acid (SCA 4 carbons)
SCA reacts with FAD to make FADH2 this make furmic acid (FA 4 carbons)
FA reacts with NAD+ to make NADH and this makes OAA and the cycle starts over.

14. Stage 3: Krebs Cycle Products One CO2 (2 total) One ATP (2 total)
One FADH2 (2 total)
Three NADH (6 total)

15. Stage 4: Electron Transport Chain
Occurs on the inner membrane of the mitochondria

16. NADH changes to NAD+ and releases 2 high energy e- into the ETC.
The e- makes its way from the matrix through the inner membrane to the intermembrane space then back to the matrix.
Each step in the ETC releases energy and this energy is used to force H+ ions out into the intermembrane space. One of the steps also creates water from the H+ ions and the O2 present in the mitochondria

17. 4. The charge on the H+ ions builds up and they flow back into the matrix through the ATP synthase complexes producing 3 ATP
5. FADH2 goes through the exact same process but in different locations on the mitochondria.

18. Stage 4: ETC and Chemiosmosis
NADH changes to NAD+ and releases 2 high energy e- into the ETC.
The e- makes its way from the matrix through the inner membrane to the intermembrane space then back to the matrix.
Each step in the ETC releases energy and this energy is used to force H+ ions out into the intermembrane space. One of the steps also creates water from the H+ ions and the O2 present in the mitochondria
The charge on the H+ ions builds up and they flow back into the matrix through the ATP synthase complexes producing 3 ATP
FADH2 goes through the exact same process but in different locations on the mitochondria.

19. Stage 4: ETC and Chemiosmosis
FADH2 is not as efficient as making ATP as NADH.
Instead of 3 ATP being produced by the FADH2 only 2 ATP are produced.
Because these are oxidation reactions these are referred to as oxidative ATP synthesis.

20. Stage 4: ETC and Chemiosmosis
Products:
H2O
3 NADH’s 3 ATP
Total of 18 ATP
FADH2 2 ATP
Total of 4 ATP

21. Energy Produced in CR Glycolysis yields two ATP
The two NADH from Glycolysis are converted to FADH2 which yield 4 ATP
The two NADH from pyruvate oxidation yield 6 ATP
Kreb Cycle yields 2 ATP  1 ATP per cycle (2 pyruvate)
The 6 NADH from Kreb yield 18 ATP
The 2 FADH2 from the Kreb cycle yield 4 ATP
For a grand total of 36 ATP from one glucose molecule.

22. Energy Produced in CR
Remember we said that Glucose had the chemical potential energy of 100 however in the most ideal conditions only 36 ATP are produced.
Often 30 ATP

23. Overall Equation
Glucose+ 6O2+ 36 ADP+P 6CO2+6H2O+ 36ATP

24. Assignment Complete Section 7.3 Questions on page 220: 1 - 10
Create your own steps for CR to help you memorize.