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2. Standardized Test Prep
Resources
Chapter Presentation
Visual Concepts
Transparencies
Standardized Test Prep

3. Chapter 7 Table of Contents Section 1 Glycolysis and Fermentation
Cellular Respiration
Table of Contents
Section 1 Glycolysis and Fermentation
Section 2 Aerobic Respiration

4. Section 1 Glycolysis and Fermentation
Chapter 7
Objectives
Identify the two major steps of cellular respiration.
Describe the major events in glycolysis.
Compare lactic acid fermentation with alcoholic fermentation.
Calculate the efficiency of glycolysis.

5. Harvesting Chemical Energy
Section 1 Glycolysis and Fermentation
Chapter 7
Harvesting Chemical Energy
Cellular respiration is the process by which cells break down organic compounds to produce ATP.
Both autotrophs and heterotrophs use cellular respiration to make CO2 and water from organic compounds and O2.
The products of cellular respiration are the reactants in photosynthesis; conversely, the products of photosynthesis are reactants in cellular respiration.
Cellular respiration can be divided into two stages: glycolysis and aerobic respiration.

6. Photosynthesis-Cellular Respiration Cycle
Section 1 Glycolysis and Fermentation
Chapter 7
Photosynthesis-Cellular Respiration Cycle

7. Section 1 Glycolysis and Fermentation
Chapter 7
Cellular Respiration

8. Section 1 Glycolysis and Fermentation
Chapter 7
Glycolysis
Cellular respiration begins with glycolysis, which takes place in the cytosol of cells.
During glycolysis, one six-carbon glucose molecule is oxidized to form two three-carbon pyruvic acid molecules.
A net yield of two ATP molecules is produced for every molecule of glucose that undergoes glycolysis.

9. Section 1 Glycolysis and Fermentation
Chapter 7
Glycolysis

10. Section 1 Glycolysis and Fermentation
Chapter 7
Glycolysis

11. Section 1 Glycolysis and Fermentation
Chapter 7
Fermentation
If oxygen is not present, some cells can convert pyruvic acid into other compounds through additional biochemical pathways that occur in the cytosol. The combination of glycolysis and these additional pathways is fermentation.
Fermentation does not produce ATP, but it does regenerate NAD+, which allows for the continued production of ATP through glycolysis.

12. Cellular Respiration Versus Fermentation
Section 1 Glycolysis and Fermentation
Chapter 7
Cellular Respiration Versus Fermentation

13. Fermentation, continued
Section 1 Glycolysis and Fermentation
Chapter 7
Fermentation, continued
Lactic Acid Fermentation
In lactic acid fermentation, an enzyme converts pyruvic acid into another three-carbon compound, called lactic acid.

14. Section 1 Glycolysis and Fermentation
Chapter 7
Fermentation

15. Fermentation, continued
Section 1 Glycolysis and Fermentation
Chapter 7
Fermentation, continued
Alcoholic Fermentation
Some plants and unicellular organisms, such as yeast, use a process called alcoholic fermentation to convert pyruvic acid into ethyl alcohol and CO2.

16. Two Types of Fermentation
Section 1 Glycolysis and Fermentation
Chapter 7
Two Types of Fermentation

17. Chapter 7 Comparing Aerobic and Anaerobic Respiration
Section 1 Glycolysis and Fermentation
Chapter 7
Comparing Aerobic and Anaerobic Respiration

18. Efficiency of Glycolysis
Section 1 Glycolysis and Fermentation
Chapter 7
Efficiency of Glycolysis
Through glycolysis, only about 2 percent of the energy available from the oxidation of glucose is captured as ATP.
Much of the energy originally contained in glucose is still held in pyruvic acid.
Glycolysis alone or as part of fermentation is not very efficient at transferring energy from glucose to ATP.

19. Chapter 7 Objectives Section 2 Aerobic Respiration
Relate aerobic respiration to the structure of a mitochondrion.
Summarize the events of the Krebs cycle.
Summarize the events of the electron transport chain and chemiosmosis.
Calculate the efficiency of aerobic respiration.
Contrast the roles of glycolysis and aerobic respiration in cellular respiration.

20. Overview of Aerobic Respiration
Section 2 Aerobic Respiration
Chapter 7
Overview of Aerobic Respiration
In eukaryotic cells, the processes of aerobic respiration occur in the mitochondria. Aerobic respiration only occurs if oxygen is present in the cell.
The Krebs cycle occurs in the mitochondrial matrix. The electron transport chain (which is associated with chemiosmosis) is located in the inner membrane.

21. Chapter 7 The Krebs Cycle
Section 2 Aerobic Respiration
Chapter 7
The Krebs Cycle
In the mitochondrial matrix, pyruvic acid produced in glycolysis reacts with coenzyme A to form acetyl CoA. Then, acetyl CoA enters the Krebs cycle.
One glucose molecule is completely broken down in two turns of the Krebs cycle. These two turns produce four CO2 molecules, two ATP molecules, and hydrogen atoms that are used to make six NADH and two FADH2 molecules.
The bulk of the energy released by the oxidation of glucose still has not been transferred to ATP.

22. Section 2 Aerobic Respiration
Chapter 7
Krebs Cycle

23. Electron Transport Chain and Chemiosmosis
Section 2 Aerobic Respiration
Chapter 7
Electron Transport Chain and Chemiosmosis
High-energy electrons in hydrogen atoms from NADH and FADH2 are passed from molecule to molecule in the electron transport chain along the inner mitochondrial membrane.

24. Electron Transport Chain and Chemiosmosis, continued
Section 2 Aerobic Respiration
Chapter 7
Electron Transport Chain and Chemiosmosis, continued
Protons (hydrogen ions, H+) are also given up by NADH and FADH2.
As the electrons move through the electron transport chain, they lose energy. This energy is used to pump protons from the matrix into the space between the inner and outer mitochondrial membranes.
The resulting high concentration of protons creates a concentration gradient of protons and a charge gradient across the inner membrane.

25. Electron Transport Chain and Chemiosmosis, continued
Section 2 Aerobic Respiration
Chapter 7
Electron Transport Chain and Chemiosmosis, continued
As protons move through ATP synthase and down their concentration and electrical gradients, ATP is produced. Oxygen combines with the electrons and protons to form water.

26. Electron Transport Chain and Chemiosmosis, continued
Section 2 Aerobic Respiration
Chapter 7
Electron Transport Chain and Chemiosmosis, continued
The Importance of Oxygen
ATP can be synthesized by chemiosmosis only if electrons continue to move along the electron transport chain.
By accepting electrons from the last molecule in the electron transport chain, oxygen allows additional electrons to pass along the chain.
As a result, ATP can continue to be made through chemiosmosis.

27. Efficiency of Cellular Respiration
Section 2 Aerobic Respiration
Chapter 7
Efficiency of Cellular Respiration
Cellular respiration can produce up to 38 ATP molecules from the oxidation of a single molecule of glucose. Most eukaryotic cells produce about 36 ATP molecules per molecule of glucose.
Thus, cellular respiration is nearly 20 times more efficient than glycolysis alone.

28. A Summary of Cellular Respiration
Section 2 Aerobic Respiration
Chapter 7
A Summary of Cellular Respiration
Another Role of Cellular Respiration
Providingn cells with ATP is not the only important function of cellular respiration.
Molecules formed at different steps in glycolysis and the Krebs cycle are often used by cells to make compounds that are missing in food.

29. Summary of Cellular Respiration
Section 2 Aerobic Respiration
Chapter 7
Summary of Cellular Respiration

30. Chapter 7 Multiple Choice
Standardized Test Prep
Multiple Choice
1. Which of the following must pyruvic acid be converted into before the Krebs cycle can proceed?
A. NADH
B. glucose
C. citric acid
D. acetyl CoA

31. Multiple Choice, continued
Chapter 7
Standardized Test Prep
Multiple Choice, continued
1. Which of the following must pyruvic acid be converted into before the Krebs cycle can proceed?
A. NADH
B. glucose
C. citric acid
D. acetyl CoA

32. Multiple Choice, continued
Chapter 7
Standardized Test Prep
Multiple Choice, continued
2. Which of the following occurs in lactic acid fermentation?
F. Oxygen is consumed.
G. Lactic acid is converted into pyruvic acid.
H. NAD+ is regenerated for use in glycolysis.
J. Electrons pass through the electron transport chain.

33. Multiple Choice, continued
Chapter 7
Standardized Test Prep
Multiple Choice, continued
2. Which of the following occurs in lactic acid fermentation?
F. Oxygen is consumed.
G. Lactic acid is converted into pyruvic acid.
H. NAD+ is regenerated for use in glycolysis.
J. Electrons pass through the electron transport chain.

34. Multiple Choice, continued
Chapter 7
Standardized Test Prep
Multiple Choice, continued
3. Which of the following is not a product of the Krebs cycle?
A. CO2
B. ATP
C. FADH2
D. ethyl alcohol

35. Multiple Choice, continued
Chapter 7
Standardized Test Prep
Multiple Choice, continued
3. Which of the following is not a product of the Krebs cycle?
A. CO2
B. ATP
C. FADH2
D. ethyl alcohol

36. Multiple Choice, continued
Chapter 7
Standardized Test Prep
Multiple Choice, continued
4. In which way is cellular respiration similar to photosynthesis?
F. They both make G3P.
G. They both involve ATP.
H. They both involve chemiosmosis.
J. all of the above

37. Multiple Choice, continued
Chapter 7
Standardized Test Prep
Multiple Choice, continued
4. In which way is cellular respiration similar to photosynthesis?
F. They both make G3P.
G. They both involve ATP.
H. They both involve chemiosmosis.
J. all of the above

38. Multiple Choice, continued
Chapter 7
Standardized Test Prep
Multiple Choice, continued
5. ATP is synthesized in chemiosmosis when which of the following moves across the inner mitochondrial membrane?
A. NADH
B. oxygen
C. protons
D. citric acid

39. Multiple Choice, continued
Chapter 7
Standardized Test Prep
Multiple Choice, continued
5. ATP is synthesized in chemiosmosis when which of the following moves across the inner mitochondrial membrane?
A. NADH
B. oxygen
C. protons
D. citric acid

40. Multiple Choice, continued
Chapter 7
Standardized Test Prep
Multiple Choice, continued
The illustration shows
part of a biochemical pathway. Use the illustration to
answer the question that follows.
6. This reaction occurs during which of the following processes?
F. Krebs cycle
G. acetyl CoA formation
H. alcoholic fermentation
J. lactic acid fermentation

41. Multiple Choice, continued
Chapter 7
Standardized Test Prep
Multiple Choice, continued
The illustration shows
part of a biochemical pathway. Use the illustration to
answer the question that follows.
6. This reaction occurs during which of the following processes?
F. Krebs cycle
G. acetyl CoA formation
H. alcoholic fermentation
J. lactic acid fermentation

42. Multiple Choice, continued
Chapter 7
Standardized Test Prep
Multiple Choice, continued
7. glycolysis : pyruvic acid :: Krebs cycle :
A. O2
B. ATP
C. lactic acid
D. acetyl CoA

43. Multiple Choice, continued
Chapter 7
Standardized Test Prep
Multiple Choice, continued
7. glycolysis : pyruvic acid :: Krebs cycle :
A. O2
B. ATP
C. lactic acid
D. acetyl CoA

44. Multiple Choice, continued
Chapter 7
Standardized Test Prep
Multiple Choice, continued
The illustration below
shows some stages and reactants of cellular respiration. Use the illustration to answer the question that follows.
8. At which of the points is ATP, the main energy currency of the cell, produced?
F. 1 only
G. 2 only
H. 1 and 3
J. 1, 2, and 3

45. Multiple Choice, continued
Chapter 7
Standardized Test Prep
Multiple Choice, continued
The illustration below
shows some stages and reactants of cellular respiration. Use the illustration to answer the question that follows.
8. At which of the points is ATP, the main energy currency of the cell, produced?
F. 1 only
G. 2 only
H. 1 and 3
J. 1, 2, and 3

46. Chapter 7 Short Response
Standardized Test Prep
Short Response
The inner membrane of a mitochondrion is folded; these folds are called cristae.
How might cellular respiration be different if the inner
mitochondrial membrane were not folded??

47. Short Response, continued
Chapter 7
Standardized Test Prep
Short Response, continued
The inner membrane of a mitochondrion is folded; these folds are called cristae.
How might cellular respiration be different if the inner
mitochondrial membrane were not folded?
Answer:
The cristae increase the surface area of the inner wall of the mitochondria, which allows more electron transport chain pathways and ATP synthase. Thus, the rate of cellular respiration is increased.

48. Chapter 7 Extended Response
Standardized Test Prep
Extended Response
Oxygen is produced during the reactions of photosynthesis, and it is used in the reactions of cellular respiration.
Part A How does oxygen get into or out of chloroplasts and mitochondria?
Part B What are the roles of oxygen in the processes of photosynthesis and cellular respiration, and how are the roles similar?

49. Extended Response, continued
Chapter 7
Standardized Test Prep
Extended Response, continued
Answer:
Part A Oxygen builds up inside chloroplasts as they produce oxygen, forming a concentration gradient—high oxygen concentration inside and low concentration outside. This causes O2 to diffuse out of the chloroplast. In mitochondria, as O2 is used up, a favorable gradient for the inward diffusion of oxygen occurs.
Part B In photosynthesis, oxygen is formed when water is split during the light reactions. This byproduct of photosynthesis is released by cells and becomes available for aerobic respiration. In aerobic respiration, oxygen is the final electron acceptor at the end of electron transport. When oxygen accepts these electrons (and protons), water is formed. Hence, water supplies oxygen for photosynthesis, and oxygen is used to form water in aerobic respiration.

50. Electron Transport Chain and Chemiosmosis
Section 2 Aerobic Respiration
Chapter 7
Electron Transport Chain and Chemiosmosis