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Chapter 10. Photosynthesis. Questions prepared by Jung Choi Georgia Institute of Technology.
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Chapter 10 Photosynthesis Questions prepared by Jung Choi Georgia Institute of Technology
Does a Tree’s Biomass Come from the Soil?A 17th-century scientist named van Helmont planted a willow sapling in a large pot with 200 pounds of dry soil and allowed it to grow, giving it only rainwater or distilled water. He weighed the soil and tree (with roots) before planting and after five years of growth. What information do you need to predict the weight of the soil remaining after five years with 99% accuracy? • the weight of the tree at start and after five years • the percentage of the tree weight that is water • the weight of leaves lost by the tree each fall • the weight of all the water added • none of the above
Photosynthesis and BiomassThe biomass (dry weight) of a tree comes primarily from • soil. • water. • air. • organic fertilizer (manure, detritus). • light.
Photosynthesis and Organic CarbonThe organic carbon in a tree comes primarily from • soil. • water. • air. • organic fertilizer (manure, detritus). • light.
What colors of light will drive photosynthesis by green plants most efficiently? • red only • yellow only • green only • blue only • red and blue
Origin of Oxygen GasWhich experiment will produce 18O2? • experiment 1 • experiment 2 • both experiment 1 and experiment 2 • neither experiment
Oxygen, Earth History, and EvolutionWhich evolutionary development caused the initial oxygenation of Earth’s atmosphere? • the evolution of the earliest photosynthetic organisms that had only PSI • the evolution of cyanobacteria with PSI + PSII • the evolution of the first land plants • the evolution of the woody plants • the evolution of flowering plants
NADPH is produced by • respiration in the mitochondria. • the citric acid cycle. • photosystem II. • photosystem I. • photorespiration.
Photosystem I and Cyclic PhotophosphorylationPhotosynthetic bacteria that have only photosystem I • can split water molecules to produce oxygen. • cannot fix carbon dioxide. • generate ATP but not NADPH. • can reduce NADP+ to NADPH but cannot make ATP through photophosphorylation. • can reduce NADP+ to NADPH and make ATP through cyclic photophosphorylation.
How are the light reactions and the Calvin cycle connected? • The light reactions provide ATP to the Calvin cycle, and the Calvin cycle provide NADPH for the light reactions. • The light reactions provide ATP and NADPH to the Calvin cycle, and the Calvin cycle returns ADP, Pi, and NADP+ to the light reactions. • The light reactions provide ATP and NADPH to the Calvin cycle, and the Calvin cycle returns reduced sugars to the light reactions. • The light reactions provide NADPH to the Calvin cycle, and the Calvin cycle provides RuBP to the light reactions. • The light reactions provide RuBP to the Calvin cycle, and the Calvin cycle returns G3P to the light reactions.
Calvin-Benson Experiment to Identify CO2 AcceptorIn this diagram, compound X is the CO2 acceptor. If CO2 is cut off, then • X and 3PG will both increase. • X will increase, 3PG decrease. • X will decrease, 3PG increase. • X and 3PG will both decrease.
Calvin-Benson Experiment to Identify CO2 AcceptorIn this diagram, compound X is the CO2 acceptor. If light is cut off, then • X and 3PG will both increase. • X will increase, 3PG decrease. • X will decrease, 3PG increase. • X and 3PG will both decrease.
Photorespiration occurs because • rubisco can use oxygen as a substrate when CO2 levels are low and oxygen levels are high. • linear electron flow cannot provide the Calvin cycle with enough ATP. • leaf cells use photorespiration to make ATP for cellular work outside the chloroplasts. • C4 plants operate a CO2 shuttle at a cost of extra ATP, provided by photorespiration. • plants need a way to consume the oxygen they produce.
Photosynthesis and RespirationA flask of duckweed in water is placed under a bank of lights on a 12-hour light, 12-hour dark cycle, next to a control flask containing only water. Assuming no change in water temperature, which flask will have the lowest dissolved oxygen (DO) concentration, at what time? • DO will be the same between the control and the duckweed-containing flask. • DO will always be higher in the flask with duckweed compared to the control. • DO will always be lower in the flask with duckweed compared to the control. • The flask with duckweed will have the lowest DO at the end of the dark cycle and the highest DO at the end of the light cycle.
Evolution of Metabolic PathwaysWhich metabolic pathways were present in the last universal common ancestor (are present in all three domains of life)? • Calvin cycle • glycolysis • citric acid cycle • chemiosmotic ATP synthesis • all of the above
Carbon Fixation and Climate ChangeHow will increasing atmospheric CO2 levels affect growth of terrestrial plants? • All plants will grow faster. • Most plants will be adversely affected. • C3 plants will grow faster, with no effect on C4 plants. • C4 plants will thrive, while C3 plants will suffer. • It depends on changes in the local climate.