Study questions Test 3. Plant Structure Cntd. Photosynthesis

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1 Study questions Test 3 Plant Structure Cntd. 1. Describe the internal structure of typical leaf and functions of each tissue in it. 2. How are guard cells different from other leaf epidermal cells? 3. Describe how gas exchange happens thru stomata CO 2, H 2 O and O Compare Monocots and Eudicots with regard to stem and root tissues. 5. Describe Eudicot stem and root secondary growth describe the contribution of intrafascicular and interfascicular vascular cambia and cork cambium to the secondary growth. Photosynthesis 1. What is the function of the enzyme ribulose bisphospate carboxylase/oxygenase? Binding RuBP to CO2 to start Calvin cycle - it has an affinity for both O2 and CO2 2. In mitochondria, chemiosmosis translocates protons from the matrix into the intermembrane space, whereas in chloroplasts, chemiosmosis translocates protons from. Stroma to the thylakoid space (into granum lumen) 3. What is the primary function of the light reactions of photosynthesis? To produce ATP and NADPH 4. Briefly describe the relationship between photosynthesis and respiration? Photsynthesis stores energy in complex organic molecules, while respiration releases energy from complex molecules (Equations can be written in opposite directions) 5. As a research scientist, you measure the amount of ATP and NADPH consumed by the Calvin cycle in 1 hour. You find 30,000 molecules of ATP consumed, but only 20,000 molecules of NADPH. Where did the extra ATP molecules come from? Cyclic electron flow

2 6. Some photosynthetic organisms contain chloroplasts that lack photosystem II, yet are able to survive (Photosystem I was the first to evolve). The best way to detect the lack of photosystem II in these organisms would be. To test for liberation of O2 in the light 7. Which of the following statements about the light reactions of photosynthesis are true? Chlorophylls (and other accessory pigments) in antennae absorb light energy, which excites electrons in all those pigments. These electrons will then flow into electron transport chains. ATP is generated by photophosphorylation. Splitting of water molecules provides a source of electrons. 8. Which of the following does not occur during the Calvin cycle Release of oxygen, excitation of Chlorophyll molecules, synthesis of ATP 9. What are the conditions that promote photorespiration? High temperature, too much light, low CO2, high O2, plant stress 10. All of the events listed below occur in the light reactions of photosynthesis except. Water splitting, carbon dioxide is incorporated into PGA, O2 release, excitation of chlorophyll 11. Light reactions of photosynthesis supply the Calvin cycle with ATP and NADPH 12. What does cyclic electron flow in the chloroplast produce? ATP 13. Organisms that can exist using light as an energy source and an inorganic form of carbon and other raw materials are called. photoautotrophs

3 14. The reaction-center chlorophyll of photosystem I is known as P700 because This reaction center chl a is best at absorbing light with a wavelength of 700 nm 15. In the thylakoid membranes, what is the main role of the antenna pigment molecules? Harvest photons and transfer light energy to the reaction-center chlorophyll mainly by resonance 16. Photorespiration lowers the efficiency of photosynthesis by preventing the formation of the potential number of 3-phosphoglycerate molecules 17. Write a statement that best describes the relationships between the light reactions and the Calvin cycle? Light reactions provide ATP and NADPH to the Calvin cycle, and Calvin cycle returns ADP, Pi, and NADP+ to the light reactions. 18., but not heterotrophs, can nourish themselves beginning with and other nutrients that are inorganic. Autotrophs 19. In mechanism, photophosphorylation is most similar to. Oxidative phosphorylation in cellular respiration 20. Which type of organism obtains energy by metabolizing molecules produced by other organisms? Autotrophs, Decomposers Heterotrophs 21. Suppose the interior of the thylakoids of isolated chloroplasts were made acidic and then transferred in the dark to a ph-8 solution. What would be likely to happen? The isolated chloroplasts will make ATP

4 22. Assume a thylakoid granum is somehow punctured so that the interior of the thylakoid granum is no longer separated from the stroma. This damage will have the most direct effect on which of the following processes? Synthesis of ATP, Synthesis of NADPH, Water splitting 23. Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle? ATP and NADPH 24. What does the chemiosmotic process in chloroplasts involve? Establishment of a proton gradient 25. Plants that fix CO2 into organic acids at night when the stomata are open and carry out the Calvin cycle during the day when the stomata are closed are CAM plants 26. Which statement regarding events in the functioning of photosystem II is false? P680 chlorophyll donates a pair of protons to NADPH, which is thus converted to NADP+ Photosystem I is involved in making NADPH 27. How many carbon dioxide molecules must be added to RuBP to make a single molecule of glucose? In C4 photosynthesis, carbon fixation takes place in the cells, and then is transferred as malic or aspartic acid to cells, where carbon dioxide is released for entry into the Calvin cycle Mesophyll; bundle-sheath 29. Compare Photoautotrophs and heterotrophs. 30. Compare autotrophic tissues and heterotrophic tissues in plants. 31. Describe sink and source relationship in plants. How do some tissues change their trophic statuses? 32. Briefly describe structures and functions of porphyrin ring and phytol tail in chlorophyll molecule.

5 33. What are differences between chl a and chl b molecules in terms of both chemical structure and light absorption characteristics. 34. Why do we say plants do all types of ADP phosphorylations? 35. Write the balanced equation for the basic chemical reaction of photosynthesis and show its redox steps. 36. Why does photosynthesis need both energy (ATP) and reducing power (NADPH)? 37. Why are NADH and NADPH considered versatile carriers of reducing power? 38. What is the ultimate source of electrons for synthesizing NADPH? 39. Draw a sketch of a chloroplast showing all membranous and non membranous parts comment on their functions. 40. Using a sketch of a chloroplast, show the molecular and functional connection between light dependent and light independent reactions of photosynthesis. 41. What can happen to the electrons that are excited in reaction center chl a what is photochemistry specifically? 42. What is the difference between absorption spectrum and action spectrum? 43. Compare chl b with carotenoids as molecules of energy transfer in the light harvesting antennae complexes of PSs? 44. Describe the nature of the PSs, and their reaction centers. What is the difference in chl b content in PSI vs. PSII? 45. Sketch PSI and PSII and their respective e transport chains working together. 46. Why is PSI reaction center called P700 but PSII reaction center P680? 47. What is the significance of PQ and Cyt in terms of chemiosmosis? 48. What is the significance of H+ impermeable membrane of granum for chemiosmosis? 49. What is the significance of proton motive force thru ATP synthase in photosynthesis? 50. Describe the location and function of FNR? 51. What are noncyclic and cyclic electron transports in light dependent reactions? Discuss their significance to the overall process of photosynthesis. 52. Describe/discuss RUBISCO what is its general affinity to CO 2 vs. O 2? 53. Why are light independent reactions happen specifically in stroma? 54. Describe carbon fixation, reduction, allocation/release of G3P and regeneration of RuBP. 55. Sketch the Calvin/Benson cycle for fixing 3 CO 2 molecules showing the use of NADPH and ATP specifying numbers of molecules of substrates, ATP and NADPH. 56. What is the significance of 3PGAL in anabolic metabolism of plants? 57. What is light compensation point? 58. Describe what different processes happen in chloroplasts in night vs. day. 59. What environmental factors and plant structural adaptations must have been conducive to the evolution of C4 cycle in some plants? 60. What is photorespiration what organelles are involved in it, and what happens in those organelles? 61. Why is photorespiration common in C3 plants and is considered wasteful? 62. Describe Kranz anatomy?

6 63. In C4 plants, what specifically happens in bundle sheath cells vs. mesophyll cells? 64. What environmental factors increase photorespiration? 65. What is the difference between CAM plants and C4 plants? 66. CAM ensures survival rather than growth describe. Plant Hormones 1. Define plant hormones also use the common characteristics. 2. Describe basic chemical structures of 5 main hormones. 3. Identify main sites of synthesis and functions of the above 5 hormones. 4. Describe Brassinosteroids, Jasmonic acid and Salicylic acid and their hormonal functions. 5. What is 2,4 D? 6. Describe how apical dominance, branch bud function and growth of vascular cambium are regulated. 7. Describe how Auxin and Cytokinin interact during plant growth. 8. Describe how Auxin and Gibberellin interact in producing new vascular tissue. 9. Describe how Auxin and Ethylene interact during leaf/fruit fall. 10. Describe phototropism and gravitropism use phototropin, statoliths and auxin in your answer. 11. Describe vernalization whch hormone can substitute vernalization requirements in some plants? 12. Explain Pr Pfr balance in circadian and seasonal changes in plant metabolism and growth patterns. 13. Discuss agricultural applications of plant hormones.