1. Section 1: Energy and Living Things
Chapter 5
Photosynthesis and Cellular Respiration
Section 1: Energy and Living Things
Section 2: Photosynthesis
Section 3: Cellular Respiration 1

2. Energy and Living Things
Section 1
Energy and Living Things
Objectives:
Analyze the flow of energy through living systems.
Compare the metabolism of autotrophs with that of heterotrophs.
Describe the role of ATP in metabolism.
Describe how energy is released from ATP. 2

3. Energy and Living Things
Section 1
Energy and Living Things
Energy in Living Systems
Building Molecules That Store Energy Autotrophs make their own food by using energy from sunlight or inorganic substances to build organic compounds. Many autotrophs make food by the process of photosynthesis.
Breaking Down Food for Energy Energy from sunlight flows through living systems, from autotrophs to heterotrophs. Heterotrophs release the energy in food through the process of cellular respiration. 3

4. Energy and Living Things
Section 1
Energy and Living Things
Energy in Living Systems continued
Transfer of Energy to ATP Cellular respiration releases much of the energy in food to make ATP, the energy “currency” inside cells. 4

5. Energy and Living Things
Section 1
Energy and Living Things
ATP
ATP Releases Energy ATP supplies cells with energy needed for metabolism. Energy is released upon the breakdown of ATP to ADP. 5

6. Photosynthesis Objectives:
Section 2
Photosynthesis
Objectives:
Summarize how energy is captured from sunlight in the first stage of photosynthesis.
Analyze the function of electron transport chains in the second stage of photosynthesis.
Relate the Calvin cycle to carbon dioxide fixation in the third stage of photosynthesis.
Identify three environmental factors that affect the rate of photosynthesis. 6

7. Photosynthesis Using the Energy in Sunlight
Section 2
Photosynthesis
Using the Energy in Sunlight
The Stages of Photosynthesis Photosynthesis has three stages. First, energy is captured from sunlight. Second, energy is temporarily stored in ATP and NADPH. Third, organic compounds are made using ATP, NADPH, and carbon dioxide. 7

8. Photosynthesis Stage One: Absorption of Light Energy
Section 2
Photosynthesis
Stage One: Absorption of Light Energy
Pigments Pigments, such as chlorophyll, absorb light energy during photosynthesis.
Production of Oxygen During photosynthesis, water molecules are split to release oxygen by an enzyme inside structures called thylakoids. 8

9. Photosynthesis Stage Two: Conversion of Light Energy
Section 2
Photosynthesis
Stage Two: Conversion of Light Energy
Electron Transport Chains Electrons excited by light travel through electron transport chains, in which ATP and NADPH are produced. 9

10. Photosynthesis Stage Three: Storage of Energy
Section 2
Photosynthesis
Stage Three: Storage of Energy
Calvin Cycle Through carbon dioxide fixation, often by the Calvin cycle, carbon dioxide in the atmosphere is used to make organic compounds, which store energy.
Factors that Affect Photosynthesis Photosynthesis is directly affected by environmental factors such as the intensity of light, the concentration of carbon dioxide, and temperature. 10

11. Cellular Respiration Objectives:
Section 3
Cellular Respiration
Objectives:
Summarize how glucose is broken down in the first stage of cellular respiration.
Describe how ATP is made in the second stage of cellular respiration.
Identify the role of fermentation in the second stage of cellular respiration.
Evaluate the importance of oxygen in aerobic respiration. 11

12. Cellular Respiration Cellular Energy
Section 3
Cellular Respiration
Cellular Energy
The Stages of Cellular Respiration Cellular respiration has two stages.
Glycolysis The first stage of cellular respiration is called glycolysis.
Aerobic and Anaerobic Respiration The second stage of cellular respiration is either aerobic respiration (in the presence of oxygen) or anaerobic respiration (in the absence of oxygen). A large amount of ATP is made during aerobic respiration. NAD+ is recycled during the anaerobic process of fermentation. 12

13. Cellular Respiration Stage One: Breakdown of Glucose
Section 3
Cellular Respiration
Stage One: Breakdown of Glucose
Glycolysis Glucose is broken down to pyruvate during glycolysis, making some ATP. 13

14. Cellular Respiration Stage Two: Production of ATP
Section 3
Cellular Respiration
Stage Two: Production of ATP
Krebs Cycle The Krebs cycle is a series of reactions that produce energy-storing molecules during aerobic respiration.
Electron Transport Chain During aerobic respiration, large amounts of ATP are made in an electron transport chain. 14

15. Cellular Respiration Fermentation in the Absence of Oxygen
Section 3
Cellular Respiration
Fermentation in the Absence of Oxygen
Fermentation When oxygen is not present, fermentation follows glycolysis, regenerating NAD+ needed for glycolysis to continue.
Lactic Acid Fermentation In lactic acid fermentation, pyruvate is converted to lactate. 15

16. Cellular Respiration Fermentation in the Absence of Oxygen continued
Section 3
Cellular Respiration
Fermentation in the Absence
of Oxygen continued
Alcoholic Fermentation In alcoholic fermentation, pyruvate is broken down to ethanol, releasing carbon dioxide.
Production of ATP Although a small amount of ATP is made during fermentation, most of a cell’s ATP is made during aerobic respiration. 16