1. Cellular Respiration and Fermentation Chapter 9
Big Idea #1

2. Chemical Energy and Food
Organisms get the energy they need from food!
How do cells use this food?
They don’t just burn food, they break it down gradually getting all the nutrients and energy out

3. Chemical Energy and Food
Energy stored in food is expressed in units of calories
The amount of energy needed to raise 1 gram of water by 1° Celsius
1 gram of glucose releases 3811 calories of heat energy when it is used

4. Chemical Energy and Food
The Calorie (big C) that you see on food labels is actually a kilocalorie, or 1000 calories.

5. Chemical Energy and Food
So only plants break down food right?
WRONG!
All living organisms break down energy sources
This is called cellular respiration

6. Cellular Respiration
If oxygen is available, energy is released from food
Here is a summary:
Oxygen + sugar  carbon dioxide water + ENERGY

7. OR 6O2 + C6H12O6  6CO2 + 6H2O + ENERGY

8. Cellular Respiration There are 3 stages of cellular respiration
Glycolysis
Kreb’s cycle
Electron transport chain

10. Cellular respiration These stages are called pathways
Pathways that require oxygen are aerobic
Kreb’s cycle
Electron transport chain

11. Pathways that DO NOT require oxygen are anaerobic
Cellular Respiration
Pathways that DO NOT require oxygen are anaerobic
glycolysis

12. What is the relationship between photosynthesis and cellular respiration?
Photosynthesis “deposits” the energy and cellular respiration “withdraws” that energy.

13. Photosynthesis removes CO2 from the atmosphere and cellular respiration puts it back.
Photosynthesis releases O2 into the atmosphere and cellular respiration uses that O2 to release energy from the food.

14. 9.1 Quiz
In what ways are cellular respiration and photosynthesis considered opposite processes?
The Greek word glukus means “sweet,” and the Latin word lysis refers to a process of loosening or decomposing. Based on this information, write a definition for the word glycolysis.

15. Review There are 3 stages of cellular respiration Glycolysis
produces only a small amount of energy.
Most of glucose’s energy (90%) remains locked in the chemical bonds of pyruvic acid at the end of glycolysis.

16. Review
2. Kreb’s cycle - During the Krebs cycle, a little more energy is generated from pyruvic acid.

17. Review
3. Electron transport chain - produces the bulk of the energy in cellular respiration by using oxygen, a powerful electron acceptor.

18. Review Aerobic processes require oxygen to take place Kreb’s cycle
Electron transport chain

19. Review Anaerobic processes DO NOT require oxygen to take place
glycolysis

20. The Process of Cellular Respiration
Glycolysis is the first step of CR
Means “sugar breaking”
Involves many steps transforming glucose
The end result is 2 molecules of a 3-carbon molecule called pyruvic acid and 2 ATP

21. Fill in your chart: Glycolysis Materials used/consumed Materials
produced/made (net total)
2 ATP
1 sugar/glucose (C6H12O6)
2 NADH
2 Pyruvic Acid

22. In the presence of oxygen, pyruvic acid produced in glycolysis moves into Kreb’s cycle
Named after Hans A. Krebs, British biochemist

23. During Kreb’s cycle, pyruvic acid is broken into carbon dioxide (CO2) in a series of energy extracting steps
This happens in the mitochondrial matrix

24. 2 ATP molecules are produced, along with many electrons and CO2 molecules

25. Fill in your chart: Kreb's Cycle Materials used/consumed
Materials produced/made
2 pyruvic acids (2 cycles)
2 ATP
8 NADH
6 CO2
1 citric acid

26. Electron Transport Chain
Electrons come from both glycolysis and Kreb’s cycle
The electron transport chain uses the high energy electrons from glycolysis and Kreb’s cycle to convert ADP  ATP

27. Electron Transport Chain: Step 3
Hydrogen Ion Movement
Channel
Mitochondrion
Intermembrane
Space
ATP synthase
Inner
Membrane
Matrix
ATP Production

28. Electron Transport Chain
One “cycle” of the electron transport chain yields 32 molecules of ATP
Electron Transport Chain
Materials used/consumed
Materials produced/made
NADH
H2O
32 ATP

29. The Totals How much energy does cellular respiration generate?
Together, glycolysis, the Krebs cycle, and the electron transport chain release about 36 molecules of ATP per molecule of glucose.
ATP

30. The Totals Total: 36 molecules of ATP per 1 molecule of glucose
Glycolysis: 2 ATP
Kreb’s cycle: 2 ATP
Electron Transport Chain: 32 ATP
Total: 36 molecules of ATP per 1 molecule of glucose

31. Fermentation What element does cellular respiration need to proceed?
Oxygen!
What happens when no oxygen is available for cellular respiration?
Cells proceed into fermentation

32. Fermentation
In the absence of oxygen, fermentation releases energy from food molcules by producing ATP
There are 2 types of fermentation:
Alcoholic fermentation
Lactic acid fermentation

33. Pyruvic acid + NADH  Alcohol + CO2 + NAD+
Fermentation
Alcoholic fermentation produces ethyl alcohol and carbon dioxide
Yeasts and other microorganisms
Alcoholic beverages and rising bread
Pyruvic acid + NADH  Alcohol + CO2 + NAD+

34. Fermentation
Lactic Acid Fermentation converts pyruvic acid from glycolysis into lactic acid
Process used to make cheese, yogurt, sour cream, pickles, kimchi
Muscle cells are lactic acid fermenters
Pyruvic acid + NADH Lactic acid + NAD+