1. Ch. 9 Cellular Respiration
This football player uses cellular respiration to get energy during football games

2. 9-1 Chemical Pathways
An overview of glycolysis, cell respiration, & Fermentation

3. I. Chemical energy and food

4. When you eat food energy is released
Humans use fats, proteins, and carbohydrates as sources of energy or food.
When you eat food energy is released
Calories can measure how much energy is in the food you eat
Calorie- the amt. of energy needed to raise the temp. of 1 gram of water 1oC
The fruit this lady eats will be digested &
the energy from the food will be released into her body.

5. II. Overview of cellular Respiration

6. During cellular respiration energy is released from food by breaking it down in the presence of oxygen (O2)
The equation for cellular respiration is:
6O2 + C6H12O6 → 6CO2 + 6H2O + Energy
oxygen + glucose → carbon dioxide + water + energy

7. Food is the material for the mitochondria in the cells in the body & to produce energy.
Animal Cell
Animal
Mitochondria
Plant
Plant Cell

8. Discuss w/ Partner
What chemical in organisms is used as a source of energy?
* Hint- it has three letters

9. Answer
ATP

10. III. Glycolysis

11. Glycolysis happens in the cytoplasm of the cell
Glycolysis– the process that breaks one molecule of glucose (C6H12O6) a 6- carbon compound in half into pyruvic acid, a 3- carbon compound.
Glycolysis happens in the cytoplasm of the cell
Glycolysis can take place w/ or w/o oxygen
The glycolysis pathway

12. Glycolysis results in : 2 NADH molecule 2 pyruvic acid
During glycolysis:
NAD+ becomes NADH
Pyruvic Acid (a 3-carbon molecule) is formed
Glycolysis results in :
2 ATP molecules
2 NADH molecule
2 pyruvic acid

13. What kind of molecule is NAD+? *Hint: think of photosynthesis!
Discuss w/ Partner:
What kind of molecule is NAD+?
*Hint: think of photosynthesis!

14. Answer!
An electron Carrier!
It carries hydrogen electrons like NADP+ carries hydrogen electrons during photosynthesis

15. ATP Production
At the beginning of glycolysis, the cell uses up 2 molecules of ATP to start glycolysis
4 ADP
4 ATP
2 ADP 2

16. Show How Cells Get Energy Video

17. Discuss w/ Partner:
Look at Figure 9-2 on page 222 and answer the following questions.
1. Where does the glucose used in respiration come from?
2. How do you know that this series of reactions occurs in the presence of oxygen?
3. What does glycolysis supply to the Krebs Cycle and to the electron transport chain?

18. Advantages of glycolysis:
No oxygen is needed
Takes place extremely fast thousands of ATP molecules can be produced in less than one second.
Every molecule of glucose in the bread
this little girl eats will turn into 2 ATP
molecule and 2 pyruvic acid molecules

19. IV. Fermentation

20. If no oxygen is present after glycolysis fermentation takes place
Fermentation- the release of energy from food without oxygen being present
Fermentation is an anaerobic process
Anaerobic- Oxygen is not needed (w/o oxygen)
There are two types of fermentation:
Alcoholic
Lactic Acid

21. Alcoholic Fermentation
Pyruvic acid from glycolysis forms ethyl alcohol and carbon dioxide as waste
Used by yeasts and other organisms
The equation for alcoholic fermentation after glycolysis is:
pyruvic acid + NADH → alcohol + CO2 + NAD+

22. Takes place in muscle cells during rapid exercise due to lack of O2
Lactic Acid Fermentation- forms 2 lactic acid molecules from 2 pyruvic acid molecules; results in the production of ATP
Regenerates NAD+ so glycolysis can continue
Takes place in muscle cells during rapid exercise due to lack of O2
The result: the muscle cells are able to produce ATP

23. Some unicellular organisms produce lactic acid as a waste product, which allows humans to make cheese, yogurt, etc.
The equation for lactic acid fermentation after glycolysis is:
pyruvic acid + NADH → lactic acid + NAD+

24. Does Fermentation take place with O2?
Discuss w/ Partner:
Does Fermentation take place with O2?

25. Fermentation takes place after glyco lysis if there is no oxygen!
Answer NO
Fermentation takes place after glyco lysis if there is no oxygen!