PowerPoint

1. “Cellular Respiration”
How Cells Harvest Chemical Energy
Cellular Respiration

2. Cellular Respiration
–C6H12O6 + 602  6CO2 + 6H20
– A catabolic pathway
– Oxygen is consumed as a reactant along with organic compounds.
– Involves three stages:
• Glycolysis
• Krebs Cycle
• Electron Transport Chain

4. What Is ATP?
• Adenosine Triphosphate
• Energy used by all Cells
• Organic molecule containing high-energy Phosphate
bonds

5. Chemical Structure of ATP

6. What Does ATP Do for You?
• It supplies YOU with ENERGY!

7. How Do We Get Energy From ATP?
• By breaking the high-
energy bonds
between the last two
phosphates in ATP

8. NADH and FADH2
• NAD+ traps electrons
from glucose to make
NADH (energy stored)
• Similarly, FAD+ stores
energy as FADH2

9. Where Does Cellular Respiration Take
Place?
• It actually takes place in two parts of
the cell:
– Glycolysis occurs in the Cytoplasm
– Krebs Cycle & ETC Take place in the Mitochondria

10. Review of Mitochondria Structure
• Smooth outer Membrane
• Folded inner membrane
• Folds called Cristae
• Space inside cristae called
the Matrix

11. Diagram of the Process
Occurs in Cytoplasm
Occurs in
Matrix
Occurs
across
Cristae

12. Glycolysis
1. Means “splitting of sugar”
2. Occurs in the cytosol of the cell
3. Partially oxidizes glucose (6C) into two pyruvate (3C)
molecules.
4. Occurs whether or not oxygen is present.

13. 5. An exergonic process, (meaning energy is released) most of the energy
harnessed is conserved in the high-energy electrons of NADH and in the phosphate
bonds of ATP

16. Glycolysis Summary
• Takes place in the Cytoplasm
• Anaerobic (Doesn’t Use Oxygen)
• Requires input of 2 ATP
• Glucose split into two molecules of Pyruvate
• Also produces 2 NADH and 4 ATP

17. Formation of Acetyl CoA
1. Junction between glycolysis and Krebs cycle
2. Oxidation of pyruvate to acetyl CoA
3. Pyruvate molecules are translocated from the cytosol into
the mitochondrion by a carrier protein in the mitochondrial
membrane.

18. Formation of Acetyl CoA
4. A CO2 is removed from pyruvate – making a 2C
compound.
5. Coenzyme A is attached to the acetyl group.

19. Formation of Acetyl CoA

20. Formation of Acetyl CoA

21. Krebs Cycle
• Requires Oxygen (Aerobic)
• Cyclical series of oxidation reactions that give off
CO2 and produce one ATP per cycle
• Turns twice per glucose molecule
• Produces two ATP
• Takes place in matrix of mitochondria

24. Krebs Cycle Summary
• Each turn of the Krebs Cycle also produces 3NADH,
1FADH2, and 2CO2
• Therefore, For each Glucose molecule, the Krebs
Cycle produces 6NADH, 2FADH2, 4CO2, and
2ATP

26. Electron Transport Chain
1. Located in the inner membrane of the mitochondria.
2. Oxygen pulls the electrons from NADH and FADH2
down the electron transport chain to a lower energy state
.
3. Process produces 34 ATP or 90% of the ATP in the body.

27. Electron Transport Chain
4. Requires oxygen, the final electron acceptor.
5. For every FADH2 molecule – 2 ATP’s are produced.
6. For every NADH molecule – 3 ATP’s are produced.
7. Chemiosmosis – the production of ATP using the energy of H+
gradients across membranes to phosphorylate ADP.

28. ATP Synthase
• A protein in the inner membrane in the mitochondria.
• Uses energy of the ion gradient to power ATP synthesis.
• For every H+ ion that flows through ATP synthase, one ATP
can be formed from ADP

31. Cellular Respiration in Summary
Glycolysis
– 2 ATP
– 2 NADH  4-6 ATP (Depends on how this NADH molecule gets to
the ETC. To make things simple we will say that these two NADH’s
make 4 ATP)
Formation of Acetyl CoA
– 2 NADH  6 ATP

32. Cellular Respiration in Summary
Krebs Cycle
– 2 ATP
– 6 NADH  18 ATP
– 2 FADH2  4 ATP
Grand Total = 36 ATP

33. Fermentation
• Occurs when O2 NOT present (anaerobic)
• Called Lactic Acid fermentation in muscle cells
(makes muscles tired)
• Called Alcoholic fermentation in yeast
(produces ethanol)
• Nets only 2 ATP