Effect of pH on Sucrase Activity

	Optical Density
	pH 3	pH 4	pH 5	pH 6	pH 7	pH 8	pH 9
1
2
3
Average	Minimum 5 characters, four numbers, one digital full stop. The Average value is valid, thank you. Sorry. Your value is wrong. Please try again. The valid Average value is correct, thank you.

Effect of pH on Sucrase Activity

1. State the optimum pH for sucrase activity and describe how sucrase activity changes at more acidic and more alkaline pH values.
2. Was the rate of increase of sucrase activity higher at a pH of 8.5 or a pH of 5.5?

Effect of Temperature on Sucrase Activity

	Optical Density
Temperature	10 °C (50 °F)	20 °C (68 °F)	30 °C (86 °F)	40 °C (104 °F)	50 °C (122 °F)	60 °C (140 °F)	70 °C (158 °F)
1
2
3
Average	Minimum 5 characters, four numbers, one digital full stop. The Average value is valid, thank you. Sorry. Your value is wrong. Please try again. The valid Average value is correct, thank you.

Effect of Temperature on Sucrase Activity

3. State the optimum temperature for sucrase activity and describe how sucrase activity changes at lower and higher temperatures.
4. Was sucrase activity higher at 25 ºC or 55 ºC?

Effect of Sucrose Concentration on Sucrase Activity

	Optical Density
Sucrose	35 g/L	30 g/L	25 g/L	20 g/L	15 g/L	10 g/L	5 g/L	0 g/L
1
2
3
Average	Minimum 5 characters, four numbers, one digital full stop. The Average value is valid, thank you. Sorry. Your value is wrong. Please try again. The valid Average value is correct, thank you.

Effect of Sucrose Concentration on Sucrase Activity

5. State how sucrase activity changes with increasing sucrose concentration.
6. Was the rate of increase of sucrase activity greater when sucrose concentration went from 2.5 to 7.5 g/l or when it went from 22.5 to 27.5 g/l?

pH Along the GI Tract

Organ	mouth	stomach	duodenum (first section of small intestine)	jejuneum (second section of small intestine)	ileum (third section of small intestine)	colon
pH	6.35 — 6.85	1 — 3	6	7.5	7.5	7.5 — 8

1. Referring to the table above, specifically state where in the intestine sucrase is likely most active.
2. Compare optimal temperature for sucrase activity to body temperature.
3. How would a slight fever affect sucrase activity?
4. Explain how pH of intestine and temperature of body together affect enzyme activity.
5. Explain how increasing amount of sucrose in food affects sucrase activity.
6. In the results section you were asked if rate of increase of sucrase activity was greater when sucrose concentration went from 2.5 to 7.5 g/l or when it went from 22.5 to 27.5 g/l. Explain why the rate of increase was greater for this range.
7. In this experiment, if the sucrose concentration were increased to 70 g/l would you expect sucrase activity to be significantly higher than the activity at 35 g/l. Explain your answer.
8. Restate your predictions that were correct and give the data from your experiment that supports them. Restate your predictions that were not correct and correct them, giving the data from your experiment that supports the corrections.

1. Myosin ATPase is an enzyme that is involved in muscle contraction. Athletes do warm-up exercises prior to athletic performance.
   • Explain why warm-up exercises increase myosin-ATPase activity.
   • Describe how increasing myosin-ATPase activity affects muscle contraction.
2. Salivary amylase, an enzyme in saliva that breaks down starch, has an optimal pH of 6.7-7.0. Explain why salivary amylase is active in the mouth, but becomes inactive in the stomach.