Victory for the ACT Student Text 15e

352 • S CIENCE

Experiment 2 To test the effects of temperature on enzyme activity rate, one cracker and a standard amount of enzyme were placed in three beakers, each kept at different temperatures. This was also repeated using standard amounts of water in place of the enzyme. All tests were carried out at optimal pH. Starch and sugar levels (starch/sugar) from selected samples are shown in Table 2. TABLE 2 cracker + enzyme 25°C 37°C 45°C high/none moderate/moderate high/none high/none low/high high/none high/low none/high high/low moderate/moderate none/high moderate/moderate cracker +water 25°C 37°C 45°C high/none high/none high/none high/none high/none high/none high/none high/none high/none high/none high/none high/none 49. Under what conditions does salivary amylase appear to work best? A. Any pH level greater than 5 and any temperature greater than 25°C B. Any pH level greater than 5 and any temperature less than 45°C C. pH level of 9 and temperature equals 37°C D. pH level of 7 and temperature equals 37°C 50. The ingredient used as a control for both experiments is the: F. cracker. G. water. H. enzyme. J. starch/sugar level. 51. Which of the following hypotheses is supported by the results of Experiment 1? A. At the appropriate pH level, water can break down starch, but at a slower rate than salivary amylase can. B. After any given time interval, no differences in the effects of the three buffers on salivary amylase activity should be detectable. C. Salivary amylase can show activity at each of the three pH levels tested. D. The duration of time in which starch and enzyme remain in the beakers should have no effect on the amount of sugar produced. Contents of Beakers Temperatures Levels of Starch/Sugar After 3 minutes After 9 minutes After 15 minutes After 60 minutes