1. “Let’s Take a Breather”.
Cellular Respiration
“Let’s Take a Breather”.

2. Cellular Respiration
C6H12O6 + 6O > 6CO2 + 6H20 + energy (heat and ATP)
Energy
Capacity to move or change matter
Forms of energy are important to life include Chemical, radiant (heat & light), mechanical, and electrical

3. Energy can be transformed from one form to another
Chemical energy is the energy contained in the chemical bonds of molecules
Radiant energy travels in waves and is sometimes called electromagnetic energy. An example is visible light

4. Visible Spectrum of White Light

5. Other wavelengths

6. Photosynthesis converts light energy to chemical energy
Energy that is stored is called potential energy

7. Adenosine triphosphate (ATP)
Energy carrying molecule used by cells to fuel their cellular processes
ATP is composed of an adenine base, ribose sugar, & 3 phosphate (PO4) groups
The PO4 bonds are high-energy bonds that require energy to be made & release energy when broken

8. ATP is made & used continuously by cells
Every minute all of an organism's ATP is recycled
Phosphorylation refers to the chemical reactions that make ATP by adding Pi to ADP

9. Cellular Respiration Overview:
C6H12O6 + 6O > 6CO2 + 6H20 + energy (heat and ATP)
Controlled release of energy from organic molecules (most often glucose)
Glucose is oxidized (loses e-) & oxygen is reduced (gains e-)
The carbon atoms of glucose (C6H12O6) are released as CO2

10. Generates ATP (adenosine triphosphate)
The energy in one glucose molecule may be used to produce 36 ATP
Involves a series of 3 reactions --- Glycolysis, Kreb's Cycle, & Electron Transport Chain

11. Glycolysis: Occurs in the cytoplasm
Summary of the steps of Glycolysis:
a. 2 ATP added to glucose (6C) to energize it.
b. Although glycolysis makes 4 ATP, the net ATP production by this step is 2 ATP (because 2 ATP were used to start glycolysis). The 2 net ATP are available for cell use.

12. c. If oxygen is available to the cell, the pyruvate will move into the mitochondria & aerobic respiration will begin.
Net Yield from Glycolysis
4 NADH2
2 CO2
4 ATP ( 2 used to start reaction)

13. d. If no oxygen is available to the cell (anaerobic), the pyruvate will be fermented by addition of 2 H from the NADH (to alcohol + CO2 in yeast or lactic acid in muscle cells). This changes NADH back to NAD+ so it is available for step c above. This keeps glycolysis going!

14. Types of Fermentation:
A. Alcoholic Fermentation—Alcohol (Wine, Beer)
B. Lactic Acid Ferm.

15. Aerobic Respiration: Occurs in the mitochondria
Includes the Krebs Cycle & the Electron Transport Chain (ETC)
CO2 and NADH are also produced

16. Kreb's Cycle: Named for biochemist Hans Krebs
Metabolic pathway that indirectly requires O2
Kreb's Cycle is also known as the Citric acid Cycle
Requires 2 cycles to metabolize glucose
CO2 is a waste product that diffuses out of cells

17. Kreb Cycle
Produces:
6 NADH2
2 FADH2
4 CO2
2 ATP

18. Net Yield from Kreb's Cycle (2 turns)
6 NADH2
2 FADH2
4 CO2
2 ATP

19. Electron Transport Chain:
Found in the inner mitochondrial membrane
Contains 4 protein-based complexes that work in sequence moving H+ from the matrix across the inner membrane (proton pumps)
Energized e- & H+ from the 10 NADH2 and 2 FADH2 (produced during glycolysis & Krebs cycle) are transferred to O2 to produce H2O (redox reaction)
O2  +  4e-  +  4H+  2H2O

20. Electron Transport
At the end of the electron transport chain, the electrons combine with H+ ions and oxygen to form water.

21. Energy Yield from Aerobic Respiration
Glycolysis Kreb's Cycle Total
4 NADH NADH NADH2 x 3 = 30 ATP
0 FADH FADH FADH2 x 2 = 4 ATP
2 ATP ATP ATP
Total: 38 ATP

22. Most cells produce 36- 38 molecules of ATP per glucose (66% efficient)
Actual number of ATP's produced by aerobic respiration varies among cells