1. Chapter 9 Cellular Respiration and Fermentation

2. 9.1 Cellular Respiration: An Overview
Do you like to run, bike, or swim? These all are good ways to exercise. When you exercise, your body uses oxygen to get energy from glucose.
How does your body feel at the start of exercise, such as a long, slow run? How do you feel 1 minute into the run; 10 minutes into the run?
What do you think is happening in your cells to cause the changes in how you feel?
Think about running as fast as you can for 100 meters. Could you keep up this pace for a much longer distance? Explain your answer.

3. When you are hungry, how do you feel?
Imagine you are taking a test hungry, think you will do well on the test?
What’s the opposite of an autotroph?

4. Chemical Energy and Food
What are the 4 macromolecules?
Carbs, proteins, lipids, nucleic acids.
Organisms get their energy from food.
Calorie:
Amount of energy needed to raise the temperature of 1 gram of water 1 degree Celsius.

5. Our body breaks down food molecules gradually, capturing a little bit of chemical energy at key steps.

6. Through cellular respiration, oxygen is used to
Through cellular respiration, oxygen is used to release energy from glucose and produce ATP.

7. Overview of Cellular Respiration
What is cellular respiration?
Cellular respiration is the process that releases energy by breaking down food (glucose) in the presence of oxygen.
C6H12O O2  6 H2O CO Energy
glucose oxygen water carbon ATP
dioxide
What would be the problem if cellular respiration occurred in just one step?
Burn up all energy instead of a gradual release of energy

8. Stages of Cellular Respiration
We have three stages of cellular respiration.
1. Glycolysis
2. Krebs Cycle
3. Electron Transport Chain

9. Cellular Respiration: An Overview
Section 9-1
Electrons carried in NADH
Pyruvic acid
Electrons carried in NADH and FADH2
Glucose
Krebs Cycle
Glycolysis
Electron Transport Chain
glycolysis, Krebs cycle and electron transport chain 2 2 32
36 Total ATP

10. Oxygen and Energy Aerobic: “with air” Requires oxygen.
Think aerobics, people who work out need more oxygen!
Anaerobic:
“without air” Does not require oxygen.
Which process do you think gets the most ATP?

11. Comparing Photosynthesis and Cellular Respiration
Photosynthesis removes carbon dioxide from the atmosphere, and cellular respiration puts it back. Photosynthesis release oxygen into the atmosphere, and cellular respiration uses that oxygen to release energy from food.

12. 9.2 The Process of Cellular Respiration
First step in cellular respiration
Glyco / lysis – “to break glucose”
Does not need oxygen to occur
Where does glycolysis take place in the cell?
Glycolysis occurs in the cytoplasm of the cell.
Glycolysis
Process in which one molecule of glucose is broken in half, producing two molecules of pyruvic acid.

13. Glycolysis How does the cell get glycolysis going?
The cell uses energy. 2 molecules of ATP are used up.
What are the products of glycolysis?
Pyruvate and 4 ATP molecules
Glucose to two molecules of pyruvate acid

14. C. Glycolysis
Why is there only a NET of 2 ATP molecules produced during glycolysis?
2 ATP molecules were used to start reaction

15. The Krebs Cycle and Electron Transport
After glycolysis, we move to the Krebs Cycle.
Krebs Cycle:
Second stage of cellular respiration. Pyruvic acid is broken down into co2.
At the end of glycolysis, how much of the chemical energy in glucose is still unused?
Approx. 90%
Because the final stages of cellular respiration require oxygen, they are said to be aerobic.

16. The Krebs Cycle and Electron Transport
Where do the reactions of the Krebs cycle take place in the cell???
Mitochondrial matrix
(inner most compartment of the mitochondria)

17. The Krebs Cycle and Electron Transport
Second stage of cellular respiration, in which pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions

18. Electron Transport Chain
Where do the reactions of the electron transport chain take place in the cell???
Inner membrane of mitochondria

19. The Electron Transport
The Electron Transport Chain
series of proteins in which the high-energy electrons from the Krebs cycle are used to convert ADP into ATP

20. Cellular Respiration and Energy
In the presence of oxygen, the cell can produce 36 ATP molecules per one glucose molecule

21. 9.3 Fermentation
Glycolysis is ALWAYS the first step in the break down of glucose.
Glycolysis does not need oxygen to occur
If oxygen is NOT present, glycolysis is followed by anaerobic respiration.
Alcoholic Fermentation
Lactic Acid Fermentation

22. Anaerobic Respiration: Fermentation
What is fermentation?
Fermentation is a process by which cells release energy in the absence of oxygen.
Where does fermentation occur in the cell?
Cytoplasm of the cell.
Why is fermentation considered an anaerobic process?
Anaerobic is process that does not require oxygen
Fermentation does NOT require oxygen

23. Anaerobic Respiration: Fermentation
Two main types of fermentation
Alcohol fermentation
Lactic acid fermentation

24. Glycolysis Alcoholic Fermentation
What organisms use alcoholic fermentation
Yeasts and other microorganisms use alcoholic fermentation
Waste products are alcohol and carbon dioxide
What happens to the small amount of alcohol produced during the baking of bread?
Evaporates when bread is baked.

25. Glycolysis Alcoholic Fermentation
How does fermentation allow the production of ATP to continue?
NAD+ is looped to start the process over again.

26. Glycolysis Lactic Acid Fermentation
Section 9-1
Glucose
2 Pyruvic acid
2 Lactic acid
Lactic Acid Fermentation –
Lactic acid is produced by your muscles during rapid exercise when not enough oxygen is present.
Prokaryotes produce lactic acid as a waste product which is used in production of foods: yogurt, cheese, sour cream, sauerkraut, etc.

27. SUMMARY
Glycolysis
Glycolysis is ALWAYS the first step in the break down of glucose.
If oxygen is NOT present, glycolysis is followed by anaerobic respiration.
Alcoholic Fermentation
Lactic Acid Fermentation
If oxygen is present, glycolysis is followed by aerobic respiration.

28. Energy and Exercise
For short, quick bursts of energy, the body used ATP already in muscles as well as ATP made by lactic acid fermentation.
For exercise longer than about 90 seconds, cellular respiration is the only way to continue generating a supply of ATP.