Bio hw 7 photosynthesis PDF

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Bio hw Ch 7 questions/answers with Professor Vladimir Poltoratsky...

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photosynthesis

1. What happens during photosynthesis? Plants capture energy from sunlight and use it to synthesize organic molecules. 2. Sunlight provides the energy that is necessary for the synthesis of glucose from carbon dioxide. 3. A(n) autotroph can synthesize organic molecules from inorganic molecules, while a(n) heterotroph must consume food to obtain organic molecules. 4. Plants appear green because they contain: chlorophyll 5. The light reactions of photosynthesis take place in the thylakoid membrane, while the Calvin cycle occurs in the The energy required for the synthesis of glucose from carbon dioxide ultimately comes from the stroma of the chloroplast. 6. The process by which plants capture light energy and use it to synthesize glucose and other organic molecules is called photosynthesis. 7. The energy required for the synthesis of glucose from carbon dioxide ultimately comes from sunlight. 8. Match each term with the correct description Heterotroph – Must consume food to obtain organic molecules Autotroph – Produces organic molecules from inorganic molecules Photoautotroph – Uses light energy to drive the synthesis of organic molecules from inorganic molecules 9. In photosynthesis, light energy is converted to electrochemical energy, which in turn is converted to chemical energy in a sugar molecule. 10. The green color of plants is due primarily to the absorptive properties of the pigment chlorophyll found in the chloroplasts. 11. Why is light considered a form of electromagnetic radiation? Because it consists of both electric and magnetic energy 12. Where do the light reactions occur? In the thylakoid membrane 13. A pigment is a molecule that can: absorb light 14. Green plants utilize chlorophyll a and b to absorb light energy in photosynthesis. 15. Chlorophylls a and b are found bound to integral membrane proteins in the thylakoid membrane of the chloroplast. 16. What energy conversion occurs during photosynthesis? Light energy is converted to electrochemical energy, which is converted to chemical energy 17. Light is a type of electromagnetic radiation because it consists of energy in the form of electric and magnetic fields. 18. Photosystems I and II are located in: the thylakoid 19. A molecule that can absorb light energy is called a(n): pigment 20. How does an electron present in the pigment of the light-harvesting complexes become excited? Light excites an electron in a pigment found in the light-harvesting complexes of the photosystems. 21. What is the function of chlorophyll during photosynthesis? It absorbs light energy. 22. What molecule is produced by photosystem II? Oxygen

photosynthesis

23. Which of following best describes the location of chlorophyll a and b within the chloroplasts of green plants? Thylakoid membrane 24. After a pair of electrons reach QB, each enters a transport chain in the thylakoid membrane. 25. The energy that is released as electrons pass from one electron carrier to the next is used to pump hydrogen ions into the thylakoid lumen. 26. The thylakoid membrane of the chloroplast contains two independent, light capturing complexes of proteins and pigments called photosystems I and II. 27. During photosynthesis, NADPH is synthesized by: photosystem I 28. Light excite(s) electrons in pigment molecules in photosystems I and II. 29. NADP+ reductase transfers two electrons and one H+ to NADP+ to generate NADPH. 30. The electrons that exit PSII are replenished by electrons from oxidized water, which yields oxygen gas that can be used by plant cells or released to the environment. 31. The flow of electrons from PSII to PSI is called linear electron flow because electrons the electrons move linearly from PSII to PSI. 32. What happens to a pair of electrons after it reaches QB? It enters an electron transport chain in the thylakoid membrane 33. In the light reactions, ATP is generated via: chemiosmosis 34. The energy released as electrons pass from an electron carrier to another in the electron transport chain between photosystem II and photosystem I is used to: establish an electrochemical gradient pump H+ 35. A key role of PSI is to produce high-energy electrons that are used to make NADPH. 36. How is NADPH formed in PSI? NADP+ reductase adds two electrons and a H+ to NADP+ 37. The flow of electrons from PSII to PSI is considered to be: linear electron flow 38. The products of the light reactions of photosynthesis are ATP, NADPH, and O2. 39. Similar to ATP synthesis in mitochondria, ATP synthesis in chloroplasts is achieved by a(n) chemiosmosis mechanism called photophosphorylation. 40. The splitting of water in photosystem II results in the production of oxygen gas. 41. Homologous genes are similar to one another because: they are derived from the same ancestral gene 42. Which of the following are major chemical products of the light reactions of photosynthesis? oxygen NADPH ATP 43. PSI and PSII have two main components: a(n) light-harvesting complex and a(n) reaction center. 44. The light-harvesting complex is composed of several dozen pigment molecules that are anchored to transmembrane proteins.

photosynthesis

45. During resonance energy transfer, what is transferred from one molecule to another? Energy 46. During photosynthesis, oxygen is produced by: the removal of electrons from water in PS2 47. Homologous genes are similar to each other because they are derived from the same ancestral gene. 48. When a pigment molecule absorbs a photon of light, a(n) electron is boosted to a higher energy level. 49. Which of the following are components of both PSI and PSII? A light harvesting complex A reaction center 50. The photosynthetic light reactions are composed of a series of: energy transfers 51. Several dozen pigment molecules anchored to transmembrane proteins make up the light-harvesting complex of a photosystem. 52. Which of the following are products of the light reactions of photosynthesis that are used as reactants in the Calvin cycle? ATP NADPH 53. The energy of an excited electron can be transferred from one pigment molecule to another via resonance energy transfer. 54. What happens when a photon of light is absorbed by a pigment molecule? an electron is boosted to a higher level 55. In plants, which of the following is polymerized to form starch? Glucose 56. The light reactions of photosynthesis are composed of a series of energy changes. 57. Which of the following are products of the light reactions that are used by the Calvin cycle to make carbohydrates? NADPH and ATP 58. True or false: Glucose is the primary output of the Calvin cycle. False 59. What are the three phases of the Calvin cycle? Carbon fixation Regeneration of ribulose bisphosphate Reduction and carbohydrate production 60. After glucose molecules are made, they may be linked together in a polysaccharide called starch. 61. Which of the following summarizes the events of the first phase of the Calvin cycle? Atmospheric carbon dioxide is fixed into a five carbon sugar. 62. The incorporation of carbon from CO2 in the atmosphere into an organic molecule is called carbon fixation. 63. Which of the following is the primary output of the Calvin cycle? Glyceraldehyde-3-phosphate 64. The end product of phase 2 of the Calvin cycle is G3P. This molecule is used to synthesize carbohydrates and to regenerate the starting material ribulose bisphosphate.

photosynthesis

65. Sequence the phases of the Calvin cycle from first (on top) to last: carbon fixation reduction and carbohydrate production regeneration of ribulose bisphosphate 66. In the first phase of the Calvin cycle, atmospheric carbon dioxide is fixed into a fivecarbon sugar. 67. What is carbon fixation? Incorporation of carbon into an organic molecule that is not a gas 68. In the last phase of the Calvin cycle, what molecule is regenerated so that the next cycle can occur? Ribulose bisphosphate 69. The G3P produced at the end of the second phase of the Calvin cycle is directly used for which of the following? Select all that apply. make glucose or other carbohydrates regenerate ribulose bisphosphate 70. What molecule is reduced in the Calvin cycle? CO2 71. The Calvin cycle is affected by certain environmental conditions, including light intensity, water availability, and temperature. 72. What happens during photorespiration? Rubisco attaches O2 to RuBP, and CO2 is produced. 73. Which of the following is the purpose of phase 3 of the Calvin cycle? To create a new 5-carbon sugar for the "next" Calvin cycle 74. In some plants, carbon fixation yields a four-carbon molecule instead of 3GP as the first product. Such plants are known as C4 plants. 75. CAM plants avoid water loss by closing their stomata during the day and opening them at night. 76. In the Calvin cycle, CO2 is: reduced 77. Which of the following conditions affect the way the Calvin cycle operates in photosynthetic organisms? Temperature Light intensity Water availability 78. In hot dry conditions, rubisco can attach O2 to RuBP in a process called photorespiration, which ultimately produces CO2. 79. In C4 plants, the first product of carbon fixation is: a four-carbon molecule 80. How do CAM plants avoid water loss? CAM plants close their stomata during the day and open them at night....