PhysioEx 9.0 Ex. 8: Chemical and Physical Processes of Digestion - Review Sheet

4. The stomach maintains a pH of approximately 3 to 5. Do all enzymes function at this pH level? Give an example from one of the exercises.

Pepsin is an enzyme that works in the stomach and has an optimal pH between pH 1 and 4 or in acidic conditions. From our graph it can be seen that that the lowest mean percentage light transmission for pepsin is when the buffer has a pH of 2. Trypsin is an enzyme that works in the small intestine and has an optimum pH between pH 7 and 8 or in neutral conditions. From our graph it can be seen that the lowest mean percentage light transmission for trypsin is when the buffer has a pH of 8.

Amylase experiment # 2 was done to see how the pH affected the efficacy of the enzyme. First we collected all of the materials that were necessary to make this experiment. We needed five clean test tubes, the following standard solutions, 1% Starch Solution pH 3,1% Starch Solution pH 5,1% Starch Solution pH 7,1% Starch Solution pH 9,1% Starch Solution pH 11

1. Explain the effect that increasing the Na+ Cl- concentration had on osmotic pressure and why it has this effect. How well did the results compare with your prediction?

1. Sucrase will have the greatest activity at pH 6 2. Sucrase will have the greatest activity at 40 °C (104 °F) 3. Sucrase activity increases with increasing sucrose concentration until a plateau is reached.

These results shown from this experiment led us to conclude that enzymes work best at certain pH rates. For this particular enzyme, pH 7 worked best. When compared to high levels of pH, the lower levels worked better. The wrong level of pH can denature enzymes; therefore finding the right level is essential. The independent variable was the amount of pH, and the dependent being the rate of oxygen. The results are reliable as they are reinforced by the fact that enzymes typically work best at neutral pH

* By using the dropper and measuring cylinder, 3ml of 1% lipase was added into the test tube

10. Which had the greatest average 1- OD (amount of bile acid adsorbed to meal particles), the standard meal with bile acid or the

2. Describe the functional anatomy of the duct system that conveys bile from the liver and digestive juice from the pancreas to the lumen of the

3. Specifically state where in the intestine sucrase is likely to be most active (pH along GI tract).

An enzyme is a protein that acts as a catalyst to form reaction, and see the activity of the

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

We did this to test which test tube would contain the highest concentration of glucose. What we wanted to know was if the lactase would affect the function of the enzyme. Our hypothesis is the lactase functions within a narrow pH and that will change in pH would affect the function of the enzyme. We predict that if we change the environmental factors it will have an effect the function of the enzyme if the pH is outside the range in its optimum activity. Our hypothesis was then proven because the reaction only occurred in a neutral and acidic state of pH, not basic. Which means the enzymes prime ability to function is a neutral, and acidic pH range.

The objective of the lab was to examine the effects of environmental variables on the functions of an enzyme. To the point, an experiment was conducted to test the effect of pH on the function of the enzyme Amylase.

Digestion is the chemical breakdown of food into smaller components that are more easily absorbed. Digestion is a form of catabolism: a breakdown of large food molecules to smaller ones. When food enters into stomach, gastric juice starts protein digestion. Gastric juice mainly contains hydrochloric acid and pepsin. The pH value of hydrochloric in the stomach is 2, as the activity of pepsin is optimal, while it will lose its activity at pH 6.5 and above. However, pepsin will regain its activity at pH of 8. In the range of pH1 to pH6.5, pepsin will be most active at pH2, and starts to decrease its