Biology 1 of 51
8-3 The Reactions of Photosynthesis 2 of 51
Inside a Chloroplast 1. In plants, photosynthesis takes place inside chloroplasts. Plant Chloroplast Plant cells 3 of 51
Inside a Chloroplast 2. thylakoids saclike photosynthetic membranes *Inside a Chloroplast. Single thylakoid Chloroplast 4 of 51
Inside a Chloroplast 3. Grana: stack of thylakoids (A singular stack is called a granum.) Granum Chloroplast 5 of 51
Inside a Chloroplast 4. photosystems: the light-collecting units of the chloroplast. Photosystems Chloroplast 6 of 51
Inside a Chloroplast 5. The reactions of photosystems include: a. light-dependent reactions *takes place within thylakoid membranes b. light-independent reactions, or Calvin cycle. *takes place in the stroma, which is the region outside the thylakoid membranes. 7 of 51
Inside a Chloroplast Light H 2 O CO 2 NADP + ADP + P Lightdependent reactions Calvin Cycle cycle Chloroplast O 2 Sugars 8 of 51
Electron Carriers 6. Electron Carriers Transport high-energy electrons from chlorophyll to other molecules. a. NADP+: transports H+ electrons; converts into NADPH *used to help build variety of molecules the cell needs (carbohydrates) 9 of 51
Light-Dependent Reactions 7. Light-Dependent Reactions a. The light-dependent reactions require light. b. produce oxygen gas c. converts ADP into ATP d. NADP + into NADPH. 10 of 51
Light-Dependent Reactions (The light-dependent reactions use water, ADP, and NADP +. The light-dependent reactions produce oxygen, ATP, and NADPH. These compounds provide the energy to build energy-containing sugars from low-energy compounds.) 11 of 51
The Calvin Cycle 8.The Calvin Cycle (Light Independent Reaction) (ATP and NADPH formed by the light-dependent reactions contain an abundance of chemical energy, but they are not stable enough to store that energy for more than a few minutes. During the Calvin cycle plants use the energy that ATP and NADPH contain to build high-energy compounds that can be stored for a long time.) 12 of 51
The Calvin Cycle a.the Calvin cycle uses ATP and NADPH from the light-dependent reactions to produce high-energy sugars. b. Calvin cycle does not require light 13 of 51
The Calvin Cycle 9. The two sets of photosynthetic reactions work together. The light-dependent reactions trap sunlight energy in chemical form. The light-independent reactions use that chemical energy to produce stable, highenergy sugars from carbon dioxide and water. 14 of 51
Factors Affecting Photosynthesis 10. Many factors affect the rate of photosynthesis, including: Water Temperature Intensity of light 15 of 51
8-3 Continue to: - or - Click to Launch: 16 of 51
8-3 In plants, photosynthesis takes place inside the a. thylakoids. b. chloroplasts. c. photosystems. d. chlorophyll. 17 of 51
8-3 Energy to make ATP in the chloroplast comes most directly from a. hydrogen ions flowing through an enzyme in the thylakoid membrane. b. transfer of a phosphate from ADP. c. electrons moving through the electron transport chain. d. electrons transferred directly from NADPH. 18 of 51
8-3 NADPH is produced in light-dependent reactions and carries energy in the form of a. ATP. b. high-energy electrons. c. low-energy electrons. d. ADP. 19 of 51
8-3 What is another name for the Calvin cycle? a. light-dependent reactions b. light-independent reactions c. electron transport chain d. photosynthesis 20 of 51
8-3 Which of the following factors does NOT directly affect photosynthesis? a. wind b. water supply c. temperature d. light intensity 21 of 51
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