PART III: FACTORS AFFECTING THE RATE OF PHOTOSYNTHESIS
In this section you and you partner(s) will do experiments to test the influence of two environmental factors on the rate of photosynthesis. Possible factors affecting photosynthetic rate Your experience with enzyme-catalyzed reactions from minicourse 2 suggest a number of factors that might influence the rate of photosynthesis. (a) pH. Does pH affect photosynthetic rate the same way it affected the browning reaction studied in Minicourse 2? Is there an optimal pH for photosynthesis? (b) carbon dioxide (substrate) concentration. Does photosynthetic rate increase when carbon dioxide concentrations are increased (e.g., by adding sodium bicarbonate)? Does the rate approach some maximum and level off at high CO2 concentrations?
(c) color of light. Are some colors of light better than others? For example, is the rate of photosynthesis faster in blue, red, or green light? Measuring photosynthetic rate The overall equation for photosynthesis suggests several possible variable that might be measured to estimate the rate of photosynthesis. sunlight
6 CO2 + 12 H20 —————-> C6H12O6 + 6 O2 + 6 H2O
We could measure (a) the rate of consumption of carbon dioxide gas, (b) the rate of formation of glucose, or (c) the rate of release of oxygen gas. For this minicourse, you will measure the rate of oxygen formation using the “floating leaf disk” technique.
In Part III you wil need to work in a group of THREE.
Write the names of your two partners and their discussion section leaders here: