1. CELLULAR RESPIRATION
CHAPTER 9

2. 9-1 CHEMICAL PATHWAYS CHEMICAL ENERGY and FOOD
3811 calories of heat energy are produced per gram of glucose burned.
This is quite a lot of energy.
1 CALORIE = amount of energy needed to raise the temperature of 1 gram of water by 1 degree C.
9-1 CHEMICAL PATHWAYS CHEMICAL ENERGY and FOOD

3. Chemical Energy and Food
Food labels display the number of Calories and other nutritional information about a particular product.
These Calories (CAPITAL C) are actually kilocalories.
Chemical Energy and Food

4. 9-1 How much energy is in food?
when glucose is broken down completely in the presence of oxygen, then water and carbon dioxide are produced
Glycolysis is a series of enzymes catalyzes chemical reactions that change glucose one step at a time into different molecules
One molecule of glucose is broken in half producing two molecules of pyruvic acid
Pyruvic Acid is a 3-C compound

5. Chemical Energy and Food
Also called “sugar breaking”
occurs in the cytoplasm and does not need oxygen
Glycolysis only releases a small amount of energy.
Let’s find out how our cells can produce the large amounts of energy we require to perform our everyday functions.
Chemical Energy and Food

6. SECTION 9-1: AN OVERVIEW of Cellular Respiration
When oxygen is present, the products of glycolysis enter the KREBS CYCLE and the ELECTRON TRANSPORT CHAIN.
This process is called CELLULAR RESPIRATION
SECTION 9-1: AN OVERVIEW of Cellular Respiration

7. GLYCOLYSIS
Process in which one molecule of glucose is broken in half producing two molecules of pyruvic acid.
Pyruvic Acid is a 3-C compund.
Where does the need energy in Glycolysis?
To split the Glucose molecule.
Cell spends 2 ATP to begin process.
Makes a TOTAL of 4 ATP  NET GAIN = 2 ATP
What is the electron carrier in Glycolysis?

8. Glycolysis and NADH Production
NAD+ is the electron carrier.
Nicotinamide adenine dinucleotide
4 HEe- are removed and passed to NAD+
Each NAD+ accepts 2 HEe-  NADH
NAD+ helps pass energy from glucose to other cellular pathways.
Energy yield is only 2 ATP but the cell can make thousands of ATP in a short time.

9. FERMENTATION Why is this a problem for the cell?
NAD+ is limited and they quickly fill up with e-
NAD+ is required to continue Glycolysis.
FERMENTATION releases energy from food molecules in the absence of oxygen.
Cells convert NADH back to NAD+
Passes electrons back to Pyruvic Acid
TWO TYPES
Alcoholic and Lactic Acid
What does anaerobic mean?

10. Question of the DAY NOV 12 What are the reactants of fermentation?
A. ADP and NADH
B. Glucose and NADH
C. Pyruvic Acid and Carbon Dioxide
D. Pyruvic Acid and NADH
Question of the DAY NOV 12

11. Why is NAD+ essential to a cell’s ability to produce ATP?
DO NOW Nov 12

12. It transports energy from glucose to other pathways.
ANSWER

13. FERMENTATION ALCOHOLIC LACTIC ACID Yeast and microorganisms
Pyruvic acid +
NADH yields
Ethyl Alcohol +
Carbon Dioxide +
NAD+
Why does bread dough rise?
Performed in most cells
Pyruvic acid +
NADH yields
Lactic Acid + NAD+
Why do your muscles burn when engaging in strenuous activity?
FERMENTATION

14. REVIEW OF GLYCOLYSIS What are the advantages of GLYCOLYSIS?
Are there any disadvantages to GLYCOLYSIS?
REVIEW OF GLYCOLYSIS

15. 9-2: KREBS CYCLE and ETC DRAW Figure 9-6 in your NOTES
Label all the parts and write down the STEPS
ANSWER the following Questions.
Write down the question and the answer.
1. Where does the KREBS CYCLE take place?
2. How many ATP molecules are generated in one turn of the cycle?
3. How many ATP are generated per one molecule of glucose?
4. Where is most of the energy in pyruvic acid transferred to in this cycle?
5. What is FAD? What is its role in the cycle?
9-2: KREBS CYCLE and ETC

16. The Krebs Cycle 90% of energy in pyruvic acid still unused
Locked in the HE electrons
Discovered by Hans Krebs
British Biochemist in 1937
Pyruvic acid from glycolysis travels into the mitochondrion
KREBS CYCLE occurs here
The Krebs Cycle

17. The Krebs Cycle Respiration is a synonym for breathing.
Oxygen is the final electron acceptor.
This is why organisms need to breathe in oxygen.
The Krebs Cycle

18. Pyruvic Acid is broken down into carbon dioxide in a series of energy-extracting reactions.
Second stage of cellular respiration.
Also called the Citric Acid Cycle.
Citric Acid is the first compound fromed in this process.
The Krebs Cycle

19. The Krebs Cycle: STEP A 1. PA from Glycolysis enters mitochondria
2. One C from PA becomes part of CO2
Released into air
3. Remaining 2 C joined with Coenzyme A
4. Forms Acetyl Coenzyme A (CoA)
5. Acetyl CoA joins with 4 C molecule to produce Citric Acid
The Krebs Cycle: STEP A

20. 1. Citric Acid (6-C) broken down to a 4-C molecule
2 molecules of CO2 released
2. Electrons transferred to e- carriers.
Occurs 5 times throughout cycle.
NAD+  NADH FAD  FADH2
3. ADP molecule  ATP
One turn produces 4 NADH, 1 FADH2, 1 ATP
One turn = 1 Pyruvic acid
How many turns are made for 1 molecule of glucose?
The KREBS CYCLE: STEP B

21. PRODUCTS of KREBS CYCLE
What are the products of the KREBS Cycle?
ATP, NADH, FADH2, and Carbon Dioxide
How are these products used?
ATP for Cellular Activities
Carbon Dioxide is exhaled
NADH and FADH2 carry HEe- to ETC
Used to make huge amounts of ATP

22. HOMEWORK REVIEW TEXTBOOK Page 237 and 238
Answer questions and 29-30
TEXTBOOK Page 239
Answer questions 1-9
HOMEWORK REVIEW

23. Which of the following are electron carriers?
A. NAD+
B. FAD
C. NADH
D. All of the above
Question of the Day Nov 13

24. What are the products of the Krebs Cycle for 1 Molecule of glucose?
DO NOW Nov 13

25. ANSWER The KREBS Cycle produces 8 NADH, 2 FADH2, and 2 ATP
Per molecule of Glucose
These products are from 2 turns of the KREBS Cycle.
ANSWER

26. AGENDA NOV 13 BIG Question: How do organisms produce energy?
1. QotD and DO NOW
2. Chapter 9
3. Electron Transport Chain
4. STUDY GUIDES
5. Tomorrow – Review
6. TEST on FRIDAY – CHAPTER 9
AGENDA NOV 13

27. ELECTRON TRANSPORT CHAIN
HEe- from KREBS are carried to ETC.
Delivered by NADH and FADH2
STEP A: HEe- passed along the ETC
Series of Carrier Proteins
Inner membrane of Mitochondria
Electrons lose a small amount of energy for each “jump” it they make along ETC.
ELECTRON TRANSPORT CHAIN

28. Electron Transport Chain
What happens to the electrons when they reach the end of ETC?
Oxygen is the final electron acceptor.
Enzymes combine these LEe- with H ions and Oxygen to form water.

29. ETC: ENERGY MAKING STEPS
STEP B: For every 2 HEe- that pass along ETC, their energy is used to transport H+ ions from the matrix to the inner-membrane space.
How many membranes does the mitochondria have?
Concentration gradient is formed.

30. ETC: ENERGY MAKING STEPS
STEP C: ATP SYNTHASE allows the movement of H+ ions back across the inner membrane.
This movement produces energy used to make ADP + P  ATP
Each pair of HEe- that “jump” along ETC produce enough energy to produce 3 ATP

31. TOTALS FOR 1 Molecule of GLUCOSE GLYCOLYSIS produces
2 NADH and 4 ATP (2 ATP SPENT)
KREBS CYCLE produces (2 Turns)
8 NADH, 2 FADH2, and 2 ATP
ETC produces
32 ATP
TOTALS

32. The overall process of Cellular Respiration produces available to the cell.
38 ATP – 2 ATP SPENT = 36 ATP
This is 38% of the energy available in Glucose.
Where does the rest of the energy go?
It is lost as heat.
This is why we feel hot after strenuous activity.
TOTALS

33. ENERGY and EXERCISE Short Term Energy Long Term Energy
Small amounts of ATP in muscles
Lactic Acid Fermentation takes over
Enough energy to last approximately 90 seconds
Long Term Energy
Cellular respiration is needed
Releases energy slower than fermentation
Stored in the carbohydrate Glycogen
15 – 20 minutes of energy (then breaks down fats and other molecules)
Even the most conditioned athletes must pace themselves.
ENERGY and EXERCISE