Victory for the ACT Student Text 15e

S CIENCE R EVIEW • 353

52. Which of the following experimental designs would test the hypothesis that enzyme concentration can affect the rate of starch digestion? F. Using the same pH, temperature, and enzyme levels in all beakers, test additional samples at 90 minutes, 120 minutes, and 240 minutes. G. Using different pH, temperature, and enzyme levels in all beakers, test additional samples at 90 minutes, 120 minutes, and 240 minutes. H. Using the same pH and temperatures in all beakers, test additional samples with the enzyme at one-half the strength, two times the strength, and four times the strength. J. Using the same pH, temperature, and enzyme levels in all beakers, test additional samples after stirring for 3 minutes, 9 minutes, 15 minutes, and 60 minutes. 53. In Experiment 2, an additional beaker was tested at 70°C (cracker + enzyme). After 60 minutes, the sample showed high levels of starch and no sugar. Which of the following best explains this result? A. All the starch was destroyed at this high temperature. B. The enzyme does not work at all at this high temperature. C. Starch cannot be detected at this high temperature. D. Iodine and sugar indicators cannot function properly at this high temperature.

54. On the basis of the results of Experiment 1, what would probably occur if Experiment 2 were carried out at a pH level of 5? F. Digestion of starch to sugar would slowly begin in the beakers containing crackers plus water. G. Overall, digestion of starch to sugar would probably take place less ‡ˆϐ‹…‹‡–Ž›Ǥ H. Overall, digestion of starch to sugar would probably take place more ‡ˆϐ‹…‹‡–Ž›Ǥ J. The experimental results would not change.