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Chemical and physical processes of digestion physio8 lab
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turtle72s
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For a more comfortable homework help experience, try HomeworkClinic.com.
Chemical and physical processes of digestion
Name ___________________ __________

Please write your answers in red.  Submit this file after completion in the appropriated e-folder in blackboard.
   
Carbohydrate Digestion
The following questions refer to Activity 1: Assessing Starch Digestion by Salivary Amylase.
1. At what pH did you see the highest activity of salivary amylase? Why?
2. How do you know that the amylase did not have any contaminating maltose? Maltose is a reducing sugar so test the amylase preparation with Benedict's solution as a control. If the Benedict's solution does not change color when heated with the amylase then it does not contain maltose or any reducing sugar.

3. What effect did boiling have on enzyme activity? Why? 
4. Describe the substrate and the subunit product of amylase.

The following questions refer to Activity 2: Assessing Cellulose Digestion.
5. Does amylase use cellulose as a substrate? Explain.
6. Did freezing have an effect on the activity of amylase? Explain.
7. Do you think that the bacterial suspension contained the enzyme cellulase (an enzyme that digests cellulose)? Why or why not?
8. What is the substrate of peptidase? Explain, based upon your results.

Protein Digestion by Pepsin
The following questions refer to Activity 3: Assessing Protein Digestion by Pepsin.

9. At which pH did you see the highest activity of pepsin? How does this correlate to the location of pepsin in the body?
10. What effect did boiling have on pepsin?
11. Was there any digested BAPNA contaminating the pepsin or deionized (DI) water? How can you tell?
12. What is the substrate in this experiment?
13. What is the usual substrate for pepsin, and what subunits are formed with pepsin activity?

14. What was the effect of decreasing the incubation time on the optical density results?
15. What effect would decreased incubation temperature have on pepsin activity? Why?
16. What was the significance of using 37°C for the incubation?

Fat Digestion by Pancreatic Lipase and the Action of Bile
The following questions refer to Activity 4: Assessing Fat Digestion by Pancreatic Lipase and the Action of Bile.
17. Describe the activity of lipase with and without the addition of bile salts. Refer to Chart 4 for pH values.
18. Is the activity of bile a chemical or a physical process? Explain.
19. What pH resulted in the maximum pancreatic lipase activity? How does this optimal pH correlate to the enzyme’s location in the body?
20. Explain whether or not we can determine fat hydrolysis in tube 5. Why or why not?
21. What is the substrate in this experiment? What subunits does lipase form?

Physical Process: Mechanisms of Food Propulsion and Mixing
The following questions refer to Activity 5: Studying Mechanisms of Food Propulsion and Mixing: Deglutition (Swallowing).

22. Explain the significance of the movement of the tongue during swallowing.
23. Describe three events that occur during the pharyngeal-esophageal phase of deglutition.
24. What was the time interval that you recorded between the first and second sound?

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Reply# 1
Joletta
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3 years ago

Have you tried doing the lab yourself first, before asking for all of the answers??



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Reply# 2
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3 years ago

yes i've tried to answer some of them but we started the lab in class but we did not finish thats why i need help



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3 years ago

1. Salivary amylase is most effective at a pH of 7.o because it evolved to function in breaking down carbohydrates in the mouth.

2.  We used a negative control to detect whether amylase was contaminated with maltose.  Deionized water was mixed with amylase and the Benedict’s test did not indicate the presence of maltose.

3. Boiling destroys a protein’s tertiary structure, hence it is denatured and no longer abale to bind the substrate.

4.  The substrate of amylase is starch and subunit product is a reducing sugar, in this case maltose.

5. Amylase is specific for starch and does not bind cellulose.

6. Freezing does not change the tertiary structure of the enzyme and so has no effect on the activity of amylase once it is brought up to a functioning temperature (37oC).

7. The bacterial suspension most likely had cellulose, which is an enzyme that specifically binds cellulose.  Evidence for its presence was a positive Benedict’s test, indicating a reducing sugar, in this case glucose.

8.  The substrate of peptidase is a protein and in our simulations it was a synthetic protein called BAPNA. Peptidase did not bind carbohydrates as shown by a negative Benedict’s test.

9. The highest activity of pepsin occurred at pH 2, which correlates well with the gastric environment that has a pH of 2.

10.Boiling had the same effect on pepsin as on amylase.

11. No digested BAPNA was found with pepsin and deionized water because there was a negative spectrophotometer result (0.00 optical density).

12. The substrate of pepsin is BAPNA and the usual substrate is protein.  The subunits are amino acids and di- and tripeptides.

13.  Decreasing incubataion time decreases optical density.

14. Temperature increases enzymatic reactions so decreasing temperature would decrease the rate of the enzymatic reaction leading to a reduced optical density.

15. 37oC is body temperature, which is the temperature at which most of these enzymes evolved to function in the human body.

16. Lipase was more effective in the presence of bile salts.  The pH of the mixture was lower with bile salts than without bile salts.

17. The activity is a physical process because it breaks up the pool of fat.

18. Maximum pancreatic lipase activity occurred at pH 7, which is the pH in the duodenum where this enzyme is found and evolved.

19. We can determine fat hydrolysis in tube 5 because we know the pH (2) and we did not see a reduction in pH, although it takes a lot more fatty acids to be produced to affect pH at such low levels.

20. Lipase binds fats or vegetable oil in this case and breaks it down into fatty acids.



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Reply# 4
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3 years ago

Have you tried doing the lab yourself first, before asking for all of the answers??

Excellent observation. Respect to aphyshelp, but laziness like this shouldn't be tolerated.



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3 years ago

Physical Process: Mechanisms of Food Propulsion and Mixing
The following questions refer to Activity 5: Studying Mechanisms of Food Propulsion and Mixing: Deglutition (Swallowing).

Explain the significance of the movement of the tongue during swallowing.
It prevents water from entering the airway.

Describe three events that occur during the pharyngeal-esophageal phase of deglutition.
Mouth, nasopharynx, and larynx are blocked; upper esophageal sphincter relaxes to open esophagus; food moves through esophagus by pressure gradients created by peristalsis.

What was the time interval that you recorded between the first and second sound?
I do not have a stethoscope nor did I have a lab partner to complete this question.



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