1. Cellular Respiration
Chapter 9

2. Chemical Energy and Food
1 g of sugar will release 3811 calories of heat energy
Calorie:
Amount of energy needed to raise the temperature of 1 g of water 1 degree Celsius
Chemical Energy and Food

3. Cellular Respiration is the process that releases energy by breaking down food molecules in the presence of oxygen.
6O2 + C6H12O6  6CO2 + 6H2O + Energy (ATP)
Reverse of Photosynthesis
Oxygen + Glucose  Carbon Dioxide + Water + Energy
Occurs in the MITOCHONDRIA of animal cells
Cellular Respiration

4. Cellular Respiration Reactants Products Oxygen Glucose Carbon Dioxide
Water
Energy (36 ATP)
Cellular Respiration

5. Cellular Respiration

6. Glycolysis is the process in which one molecule of glucose is broken in half, producing two molecules of pyruvic acid (a 3 carbon compound). This cycle requires oxygen.
“breaking glucose”
2 ATP needed to start reaction, 4 ATP are produced thus the net gain is 2 ATP.
Occurs in the cytosol of the cell
Glycolysis

7. Glycolysis ATP Production:
Before Glycolysis can begin producing energy it needs energy to get things going
At the beginning of the reaction 2 molecules of ATP are required.
Think of the needed ATP as an investment, you must put money into the bank before you can gain interest on it.
By the end of glycolysis there will be a production of 4 ATP. A net gain of 2 ATP.
Glycolysis

8. Glycolysis NADH Production
One of the reactions of glycolysis removes 4 high-energy electrons and passes them to a carrier molecule known as NAD+ (just like NADP+ in photosynthesis).
NAD+ is passing energy from glucose to other pathways in the cell
Glycolysis

9. Glycolysis Importance of Glycolysis Downfall of Glycolysis Speed:
High production of ATP in just a few milliseconds
Does not require Oxygen
Glycolysis can occur without oxygen meaning that it can supply chemical energy even when oxygen is not available!
Downfall of Glycolysis
NAD+ availability
In just a few seconds NAD+ can fill up with electrons, and without it ATP production stops
Glycolysis

10. Fermentation Fermentation: Anaerobic: not in air
Releases energy from glucose without the presence of oxygen.
Anaerobic: not in air
There are two types of fermentation: alcoholic and lactic acid.
Alcoholic fermentation is done by yeasts and some microorganisms. It produces alcohol & Carbon Dioxide
Lactic Acid is produced by muscles during rapid exercise when the body cannot supply enough oxygen.
Fermentation

11. Fermentation Reactants: Products: Reactants Products
Alcoholic Fermentation
Lactic Acid Fermentation
Reactants:
Pyruvic acid
NADH
Products:
Alcohol
Carbon dioxide
NAD+
Reactants
Pyruvic acid
NADH
Products
Lactic acid
NAD+
Unicellular organisms produce lactic acid as a waste product
Fermentation

12. Alcoholic Fermentation

13. After glycolysis 90% of chemical energy is unused, locked in Pyruvic acid
To release that energy in Pyruvic acid the cell needs to bring in oxygen.
This is how cellular respiration got its name.
After Glycolysis

14. During the Krebs Cycle, pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions.
Citric Acid is created in this cycle thus giving it the nickname Citric Acid cycle.
Net ATP Production is 2 ATP.
Occurs in the mitochondria
The Krebs Cycle

15. Step 1:
One carbon atom from the Pyruvic acid, produced in Glycolysis, becomes part of a Carbon dioxide molecule
The other 2 carbon atoms from Pyruvic acid join with coenzyme-A to make acetyl-CoA
Acetyl-CoA is made up of:
2 carbons, 1 oxygen, and 3 hydrogen
Acetyl-CoA then joins with a 4-carbon molecule producing a 6-carbon molecule (citric acid)
The Krebs Cycle

16. Step 2:
Citric acid is then broken down into a 4-carbon molecule, releasing carbon dioxide and electrons are transferred to carrier molecules
The Kreb’s Cycle

17. The Kreb’s Cycle Reactants Products Pyruvic acid Oxygen
Carbon dioxide (every time we exhale)
Electrons joining carrier molecules
ADP and P = ATP (at each turn)
NAD+ and H+ = NADH (occurs 5 times in each turn)
FAD and 2H = FADH2 (occurs 5 times in each turn)
The Kreb’s Cycle

18. Electron Transport Chain
The electron transport chain uses the high-energy electrons (NADH and FADH2 from the Krebs Cycle to convert ADP to ATP. This cycle requires oxygen.
Total ATP 32.
Electron Transport Chain

19. Electron Transport Chain
Step 1:
The high-energy electrons are passed along the ETC from one carrier protein to the next.
At the end of this the H+ ions join with O2 ions to make water
Oxygen is the final acceptor of the electrons making it essential for getting rid of low-energy electrons and hydrogen (waste of cellular respiration).
Electron Transport Chain

20. Electron Transport Chain
Step 2:
With every 2 high-energy electrons that travel down the ETC, their energy is transported to the H+ ions across the membrane. A collection of H+ ions makes the intermembrane space positively charged.
Electron Transport Chain

21. Electron Transport Chain
Step 3:
The difference in the charges allows for the formation of ATP to be formed.
As the H+ ions escape through the channels into the ATP Synthase, they begin to spin. With every spin the enzyme grabs a ADP and attaches a phosphate, forming high-energy ATP.
Electron Transport Chain

22. Totals Glycolysis Krebs Cycle Electron Transport Chain Total = 36 ATP
Uses:2 ATP
Produces: 4 ATP
Net gain: 2 ATP
Krebs Cycle
Produces:2 ATP
Electron Transport Chain
Produces:32 ATP
Total = 36 ATP
Totals

23. What causes the difference between glycolysis ATP production and the Kreb’s cycle and Electron Transport Chain?
OXYGEN

24. 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.
Energy & Exercise

25. Comparing Photosynthesis & Respiration
Cellular Respiration
Function
Energy Storage
Energy Release
General location
Leaves
Entire Body
Location
Chloroplasts
Mitochondria
Reactants
CO2 and H2O
C6H12O6 and O2
Products
Equation
6CO2 + 6H2O + energy C6H12O6 + 6O2
C6H12O6 + 6O2
6CO2 + 6H2O + energy