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

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

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

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

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

8.2 Photosynthesis: An Overview

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

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

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

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

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

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

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

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)