2. 6O2 + C6H12O6 -> 6CO2 + 6H2O + energy
Oxygen + glucose -> carbon dioxide + water + energy

3. Kreb’s Cycle (Citric Acid Cycle)
Regulated by many different enzymes
Occurs in mitochondrial matrix
A two-carbon compound attached to a co- enzyme enters
The carrier/co-enzyme is Coenzyme A

5. Just ONE ATP molecule. Not enough to live on

6. Kreb’s Cycle (Citric Acid Cycle)
Remember, this…
Happens here

7. Electron Transport Chain

8. Electron Transport Chain
Oxidizes NADH to NAD+
Creates a charged membrane and proton gradient
Makes ATP (and heat)
Oxygen is the Final Electron Acceptor
Without oxygen, you die… and that’s bad
The reduced oxygen, with protons, makes water

9. 6O2 + C6H12O6 -> 6CO2 + 6H2O + energy
Oxygen + glucose -> carbon dioxide + water + energy

11. Kreb’s and ETC What do we need to keep ETC going?
NADH, FADH2 and Oxygen
How/where does NAD+ and FAD+ get ‘recycled’?
What do we need to keep the Kreb’s Cycle going?

12. So, where does the ‘two-carbon compound’ come from?

13. Glycolysis “First” step in Cellular Respiration
Glucose is broken down into 2, 3-carbon molecules
Some ATP is made
Occurs in cytoplasm/cytosol

14. Glycolysis- occurs in cytoplasm
3 carbons
each

15. Pyruvic Acid enters mitochondrion
Pyruvic Acid is OXIDIZED
And a CO2 leaves -> Acetyl-CoA
3 carbons
each

16. Glycolysis Pyruvic Acid vs Pyruvate Two, 3-carbon molecules
A TWO-carbon molecule enters the Kreb’s Cycle…
A carbon is taken away in between
Lost as CO2

17. Cellular Respiration Glycolysis CO2 Coenzyme A 2 NAD+ 2 NADH Glucose
2 Pyruvate
Acetyl- CoA
“2” ATP
4 ATP
Kreb’s
Cycle
32 ATP!
NADH
ETC
2-carbons
water
FADH2 O2
heat
CO2

18. What if… You’re working out? Your muscles’ ATP demand increases
But ‘you’ can only supply finite oxygen…
For instance, a muscle cell needs ATP per second, but the ETCs can only supply 1000
What happens?

19. What do we need to keep THIS going? To keep this going we need to ...?
Cellular Respiration
Glycolysis
CO2
Coenzyme A
2 NAD+
2 NADH
What do we need to keep THIS going?
Glucose
2 Pyruvate
Acetyl- CoA
“2” ATP
4 ATP
Kreb’s
Cycle
NAD+ is …?
To keep this going we need to ...?
32 ATP!
NADH
ETC
2-carbons
water
FADH2 O2
heat
CO2

20. Fermentation If NAD+ is REDUCED to NADH
Then we need to OXIDIZE it back to NAD+
Glucose
2 NAD+
“2” ATP
2 NADH
4 ATP
2 Pyruvate

21. Fermentation If NAD+ is REDUCED to NADH
Then we need to OXIDIZE it back to NAD+
In the ETC, Oxygen takes the electrons
We don’t have enough oxygen, so we need to find something to take the electrons from NADH to make it NAD+

22. Fermentation Pyruvate can do that! 2 NADH 2 NAD+ 2 Lactate
Glucose
2 NAD+
“2” ATP
2 NADH
4 ATP
2 Pyruvate
2 Lactate
(Lactic Acid)

23. Fermentation
During Glycolysis, NAD+ is REDUCED to NADH (the two, 3-carbon molecules are oxidized)

25. Fermentation
During Glycolysis, NAD+ is REDUCED to NADH (the two, 3-carbon molecules are oxidized)
In fermentation, then we need to OXIDIZE it back to NAD+, so Pyruvate is REDUCED and forms lactic acid
This LOWERS your muscle pH and causes ‘fatigue’ because your muscles don’t function as well at lower pH

26. By Oxidizing NADH back to NAD+, Glycolysis can keep going
That makes 2 NET ATP
Not great, but it helps
By Oxidizing NADH back to NAD+,
Glycolysis can keep going
Glucose
2 NAD+
“2” ATP
2 NADH
4 ATP
2 Pyruvate
2 Lactate
(Lactic Acid)

27. Fermentation
Lactic Acid fermentation keeps glycolysis going and that makes some ATP (without needing Kreb’s and ETC)
This decreases pH and reduces cells’ ability to function
Also, the cells/body go in to Oxygen Debt
You ‘borrowed’ to make ATP, now you have to pay it back
With Oxygen

28. Lactic Acid – Cori Cycle
The liver stores glucose and glycogen
Lactic Acid is taken into the blood and carried to the liver
How did we get from glucose to lactic acid?
In the liver, the process is “reversed” using ATP from aerobic respiration

30. Fermentation This process can happen REALLY fast
It’s a ‘good’ source of quick ATP
NO oxygen needed

31. Fermentation NO oxygen needed Anaerobic
Takes place in cytoplasm of cell

32. Fermentation No ATP are ‘produced’ during fermentation
So why do cells do it?
It makes NAD+, which keeps Glycolysis going
THAT produces ATP

33. Obj 15
What is the relationship between ‘metabolism’, cellular respiration, energy needs, endothermy and ectothermy?
Endotherm – produces its own body heat
Ectotherm – relies on environment and behavior for body heat
Homeostasis?