1. Plants and other ______________ are the producers of the biosphere

1. Photosynthesis nourishes almost all of the living world directly or indirectly. _____________ produce their organic molecules from _____ and other ____________ raw materials are the ultimate source of __________ compounds for all ___________________organisms 1. Plants and other ______________ are the producers of the biosphere CHAPTER 10 PHOTOSYNTHESIS

2. ______________ are the _______________ of the biosphere. Some feed on plants and other animals. _____________ feed on dead organisms Most are completely dependent on _______________ for food and for __________, a byproduct of photosynthesis. • ___exits and _____ enters the leaf through microscopic pores, ___________, in the leaf. Fig. 10.3

3. A typical __________ cell has ________chloroplasts Each chloroplast has _____ membranes around a central aqueous space, the ________. In the stroma aremembranous sacs, the ____________. These have an internal aqueous space, the ___________ lumen. Fig. 10.3

4. Plants produce organic compounds and O2 from ___and _____. Using glucose as our target product, the equation describing the net process of photosynthesis is: __________________________________________ In reality, photosynthesis adds one _____ at a time: CO2 + H2O + light energy -> CH2O + O2 ________ is the general formula for a sugar.

5. 2. Photosynthesis is a ________ reaction. It reverses the direction of _______ flow in respiration. Water is split and electrons transferred with H+ from water to CO2, _________ it to sugar. ______ covalent bonds (unequal sharing) are converted to ____________ covalent bonds (equal sharing). Light boosts the ________________ of electrons as they move from water to sugar. Fig. 10.4

6. 4. _____ is generated by _____________________ for the Calvin cycle. The ____________ incorporates CO2 from the atmosphere into an organic molecule 6 steps 6. _____ is fixed into organic molecules by the Calvin Cycle 1. ___________(in thylakoids) absorbs light energy Fig. 10.5 ______________ drive Calvin cycle 2. Electrons and hydrogen are transferred to _______ 3. _________ is generated

7. A _____________________ measures the ability of a pigment to absorb various wavelengths of light. An _____________________ plots a pigment’s light absorption versus wavelength. Fig. 10.8

8. In the thylakoid are several pigments that differ in their absorption spectrum. _______________, the dominant pigment, absorbs best in the red and blue wavelengths, and least in the green. • _______________and_________________funnel the energy from other wavelengths to chlorophyll a. • _______________ also give photoprotection against excessive light. Fig. 10.9a

9. The structure of chlorophyll a and b _________ ________ ___________________ Fig. 10.10

10. _____________ (light gathering “antenna complex) • Located in the ____________________________ • contain a few hundred chlorophyll __, chlorophyll __,and ___________________ molecules. • There are two types of photosystems- _____________ and __________________ • These two photosystems work together to use light energy to generate ___________________. Reaction center • All photon energy is are transferred to a chlorophyll a molecule (the __________ ___________). Fig. 10.12

11. _____________ (light gathering “antenna complex) Located in the ________________________ contain a few hundred chlorophyll __, chlorophyll ___,and ______________ molecules. • There are two types of photosystems- ___________ and ________________ • These two photosystems work together to use light energy to generate ________________. • All photon energy is are transferred to a chlorophyll a molecule (the ________ _________). Fig. 10.12

12. Fig. 10.13

13. The light reactions use the solar power of _______ absorbed by both photosystem I and photosystem II to provide ________________ in the form of ATP and ________ _________ in the form of the electrons carried by ________. An analogy Fig. 10.14

14. 2. ___________________ –Convert ___________ energy from food molecules into ATP._____________- Convert ________energy into ATP to drive ______________ to make glucose. Compare mitochondria and chloroplasts Fig. 10.16 • 1. Both generate ATP via ______________ • ATP __________ molecules harness the proton-motive force to generate ATP as H+ diffuses back across the membrane. Mitochondria Chloroplast

15. CO2 enters the cycle and leaves as _________. Each turn of the Calvin cycle fixes _____ carbon. The actual sugar product of the Calvin cycle is glyceraldehyde-3-phosphate (G3P). 3. The Calvin cycle uses ____ and ________ to convert CO2 to ________: a closer look • For the net synthesis of one ____ molecule, the cycle must take place _______times, fixing ________ molecules of CO2. • To make one glucose molecules would require ____ cycles and the fixation of ______ CO2 molecules.

16. Each cycle fixes one carbon The Calvin Cycle 3 CO2 Carbon Fixation 3 (P-C-C-C + C-C-C-P) 3 (P-C-C-C-C-C-P) 6 ATP used “Rubisco” 3 (P-C-C-C-P + P-C-C-C-P) 3 ATP used 5 (P-C-C-C) 6 NADPH used Fig. 10.18 1 (P-C-C-C) Total energy used for 3 carbon sugar = __ ATP + ___ NADPH

17. The ____________ are not only the major route for gas exchange (CO2 in and O2 out), but also for the evaporative loss of _________. On hot, dry days plants close the stomata to conserve water, but this causes problems for photosynthesis. 4. Alternative mechanisms of ___________ ________ have evolved in hot, arid climates One solution • _________________-__________ • But photorespiration can drain away as much as _____ of the carbon fixed by the Calvin cycle • Some plants (_____________) have a mechanism to minimize photorespiration

18. The ________ fix ____ in a four-carbon compound via _______________________(PEP) to form _________________. Several thousand plants, including ____________ and corn, use this pathway. A better solution- to fix CO2 at _________ • The mesophyll cells pump these ________-carbon compounds into ________________ cells. • The bundle sheath cells strip a carbon, _________, from the four-carbon compound and return the three-carbon remainder to the mesophyll cells. • The bundle sheath cells then uses rubisco to start the __________ with an abundant supply of _____.

19. C4 photosynthesis minimizes photorespiration and enhances sugar production. C4 plants thrive in hot regions with intense sunlight. C4 plant response to hot, dry weather: CO2 is shuttled into oxaloacetate (a 4-carbon compound) Fig. 10.18 CO2 can later be shutted back into the Calvin Cycle Fig. 10.19

20. A __________ strategy to minimize photorespiration is found in succulent plants, cacti, pineapples, and several other plant families. These plants, known as _____________ for _____________________________ (CAM), open stomata during the night and close them during the day. During the night, these plants fix _________ into a variety of organic acids in mesophyll cells. During the day, the light reactions supply ATP and NADPH to the Calvin cycle and CO2 is released from the organic acids.

21. Fig. 10.20

22. In photosynthesis, the energy that enters the __________________ as sunlight becomes stored as _______________ in organic compounds. 5. Photosynthesis is the biosphere’s ______________ foundation: a review • Plants also store excess sugar by synthesizing _________. • Some is stored as starch in chloroplasts or in storage cells in roots, tubers, seeds, and fruits. Fig. 10.21