Unveiling Photosynthesis: Harnessing Energy from the Sun

1. Ch 8 Photosynthesis 8.1 Energy and Life 8.2 Photosynthesis: an Overview 8.3 The reactions of Photosynthesis

2. 8.1 Energy and Life • Plants and some other types of organisms are able to use light energy from the sun to produce food • Organisms that can produce their own energy are called Autotrophs • Heterotrophs acquire their energy by consuming

3. 8.1 Energy and Life • One of the principle chemical compounds that cells use to store and release energy is Adenosine Triphosphate (ATP) • Energy release from converting ATP to ADP is commonly used for active transport, protein synthesis and muscle contraction

4. 8.1 Energy and Life • Energy is not stored as ATP but stored as sugars and carbohydrates, ATP is only produced at it is needed

5. 8.2 Photosynthesis: An Overview • In the Process of Photosynthesis, plants use the energy of sunlight to convert water and carbon dioxide into high energy carbohydrates (Sugar and Starches) and oxygen, a waste product LIGHT 6CO2 + 6H2O ----------> C6H12O6 + 6O2 carbon dioxide + water --------> sugars + oxygen

6. 8.2 Photosynthesis: An Overview

7. 8.2 Photosynthesis: An Overview • In addition to water and carbon dioxide, photosynthesis requires light and chlorophyll, a molecule in chloroplasts

8. 8.2 Photosynthesis: An Overview • Plants gather the suns energy with light absorbing molecules called Pigments • Plants principle pigment is Chlorophyll and comes in 2 varieties, Chlorophyll A and Chlorophyll B

9. 8.3 The reactions of Photosynthesis • Chloroplasts are an organelle in plants that contain • Grana- Consists of stacks of flattened sacs called Thylakoids • Surrounding the thylakoids is a fluid called Stroma

10. 8.3 The reactions of Photosynthesis • Proteins in the thylakoid membrane organize chlorophyll and other pigments into clusters called Photosystems

11. 8.3 The reactions of Photosynthesis • Along with ATP, the Calvin cycle needs Electrons to synthesis Sugar • NADPH is the carrier of electrons in a process called Electron Transport

12. 8.3 The reactions of Photosynthesis • The light-dependant reactions produce oxygen gas and convert ADP and NADP+ into the energy carriers ATP and NADPH • I)Light energy is absorbed by electrons and passed • II)Electrons transported from stroma to inner thylakaoid • III) NADP+ converted into NADPH • IV) Transfer of electrons creates a charge that produces ATP • V) Proteins in the membrane called ATP Synthase which allow H+ to balance the charge

13. 8.3 The reactions of Photosynthesis • The Calvin Cycle uses ATP and NADPH from the light-dependant reactions to produce high energy sugars • Many steps involved in the Calvin cycle are called the Light Independent Reactions

14. 8.3 The reactions of Photosynthesis • Factors that affect Photosynthesis: • Negative Factors • Not enough CO2 • Not enough Light • Temperature too high or too low will denature Proteins • Positive Factors • More light, more photosynthesis but a Max can be reached • Pg 214 (1-5)