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Posts: 97
4 years ago
PhysioEx 9.0 Ex. 8: Chemical and Physical
Processes of Digestion - Review Sheet

 Assessing Starch Digestion by Salivary Amylase
1. List the substrate and the subunit product of amylase. _starch & maltose respectively__

2. What effect did boiling and freezing have on enzyme activity? Why? How well did the results compare with your prediction?
__Boiling caused amylase to be denatured, thus inactivating the enzyme. Freezing has no effect. The function of an enzyme is directly related to its environment, like temperature.

3. At what pH was the amylase most active? Describe the significance of this result.  pH  7.0. Amylase is most active in neutral areas, such as the mouth and the small intestine (duodenum)._

4. Briefly describe the need for controls and give an example used in this activity. _Controls are needed to validate the results of the experiment. One example is testing for sugar using Benedict's test on Amylase The negative control was used to detect if amylase was contaminated with maltose or not._

5. Describe the significance of using a 37°C incubation temperature to test salivary amylase activity. __37°C simulates an environment of normal body temperature. ___
A C T I V I T Y 2
 Exploring Amylase Substrate Specificity
1. Describe why the results in tube 1 and tube 2 are the same. _In tube #1 the amylase is hydrolyzing the starch to glucose, & in tube #2 the glucose is already present in the hydrolyzed form.__

2. Describe the result in tube 3. How well did the results compare with your prediction? _ Amylase cannot digest cellulose, so tube #3 is not positive for Benedict’s test.__

3. Describe the usual substrate for peptidase.  _A protein (BAPNA in this experiment).__

4. Explain how bacteria can aid in digestion. _Bacteria can aid in digestion by breaking down cellulose with the enzyme cellulase, humans do not produce this enzyme.
A C T I V I T Y 3
 Assessing Pepsin Digestion of Protein
1. Describe the effect that boiling had on pepsin and how you could tell that it had that effect. _Boiling denatured the enzyme. You can tell because the protein was not digested in tube #1. There was no color change & a density of 0.__

2. Was your prediction correct about the optimal pH for pepsin activity? Discuss the physiological correlation behind your results.
_Yes. The optimum pH matches the pH secreted by gastric glands. Gastric juice is also close to pH 2.___

3. What do you think would happen if you reduced the incubation time to 30 minutes for tube 5? _This would reduce digestion in tube 5.__
A C T I V I T Y 4
Assessing Lipase Digestion of Fat
1. Explain why you can’t fully test the lipase activity in tube 5. _Measurement of lipase activity uses a decrease in pH. Because the pH in Tube #5 is already very low, it is hard to tell if fatty acids are released.__

2. Which tube had the highest lipase activity? How well did the results compare with your prediction? Discuss possible reasons why it may or may not have matched. __Test tube #1 should have the highest activity because the pH is closest to that of the small intestine.__

3. Explain why pancreatic lipase would be active in both the mouth and the intestine. _Pancreatic lipase is most active at pH 7.0 The pH of the mouth is 7.0 & the pH of the small intestine is close to 8.0 so the enzyme would function in both places.___

4. Describe the process of bile emulsification of lipids and how it improves lipase activity. _Fat globules are separated into droplets by bile salts through an emulsification process which is physical not chemical, which promote lipase activity__

Hope this helps someone!
Source  PhysioEx 9.0
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32 Replies
4 years ago
You're Awesome
4 years ago
Thanks so much!
4 years ago
 Slight Smile this really helped!!tanx!
4 years ago
Thanks a bunch!!
4 years ago
Awesome! Thanks so much! This really helped me with my lab. I understand it a bit more now. Slight Smile
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4 years ago
This was SUCH a help. I needed this today Slight Smile
If you are reading this, you are awesome, and I wish you a happy and prosperous day!
4 years ago
 Smiling Face with Open Mouth and Tightly-closed Eyes Thank you so much ! Great help !
4 years ago
so basically, I LOVE YOU.
3 years ago
Quality posting for answers Slight Smile
3 years ago
Glad this is still helping people!
3 years ago
Very helpful, thank you!
3 years ago
Thank you Nerd Face
3 years ago
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