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raininginny raininginny
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12 years ago
PHYSIOEX Excerise 8 Digestion

1.   At what PH did yo see the highest activity of salivary amylase? _______
Salivary amylase is active in the mouth, which has a pH of 7.

Why?
Because saliva is where the enzyme is supposed to act

2. How do you know that the amylase did not have any contaiminating maltose?
Tube 3 showed that amylase had no contaminating maltose

3. What effect did boiling have on enzyme activity? Why?
By boiling the enzyme activity stops, because of the high temperatures killing the enzymes

4. Describe the subtrate and the subunit product of amylase
the substrate of amylase is amylose and the subunit product is glucose

5. Does amylase use cellulose as a substrate? Explain.
 Both  cellulose and starch are glucose polymers. however only starch can be digested by amylase.

6. Did freezing have an effect on the activity of amylase? Explain.
Freezing does not change the structure of the enzyme so it doesn’t have effect on the activity.


7. Do you think that the bacterial suspension contained the enzymes cellulose (an enzyme that digests cellulose)? Why or why not?
Yes I think the bacteria contained cellulase because it specifically digests cellulose. 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. What is the substrate of peptide? Explain, based upon your results.
The substrate is a synthetic protein called APNA

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

10. What effect did boiling have on pepsin?
Boiling had the same effect on pepsin as on amylase.

11. Was there any digested BAPNA containing the pepsin or deionizer (DI) water? How can you tell?
No digested BAPNA was found with pepsin and deionized water because there was a negative spectrophotometer result (0.00 optical density).


12. What is the substrate in this experiment? What is the usual substrate for pepsin, and what subunits are formed with pepsin activity?
The substrate of pepsin is BAPNA and the usual substrate is protein.  The subunits are amino acids and di- and tripeptides.

13. What was the effect of decreasing the incubation time on the optical density results?
decreasing incubation time decrease optical density

14. What effects would decrease incubation temperature have on pepsin activity? Why?
Since temerature increases enzymatic reactions when one decreases the temperature this would essentially decrease the rate of the enzymatic reaction leading to a total decrease in density.

15. What was the significance of using 37 degree C for the incubation?
Fat digestion by pancreatic lipase and the action of bile
37oC is body temperature, which is the temperature at which most of these enzymes evolved to function in the human body.

The following question refer to activity 4: Assessing fat digestion by pancreatic lipase and the action of bile

16. Describe the activity of lipase with and without the addition of bile salts. Refer to chart 4 for Ph values.
When bile salts were present, lipase was more effective.  The Ph levels were lower with bile salts than without bile salts.

17. Is the activity of bile a chemical or a physical process? Explain.
Yes it is purely chemical.  Bile acids, cholic acid and chenodeoxycholic acid as well as bilirubin are responsible for metabolism of fats and enhances digesion.  Higher concentration of bilirubin in body show a physically yellowish coloration.  This might be seen in the retina and skin. 

18. What Ph resulted in the maximum pancreatic lipase activity? How does this optimal Ph correlate to the enzyme`s location in the body?
Pancreatic lipase's optimum PH is around 8.0, which means that it works best when there is a weak alkaline solution.

19. Explain whether or not we can determine fat hydrolysis in tube 5. Why or why not?
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. What is the substrate in the experiment? What subunits does lipase form?
Lipase binds fats or vegetable oil in this case and breaks it down into fatty acids

The following question refer to activity 5: Studying mechanism of food propulsion and mixing: deglutition (swallowing).

21. Explain the significance of the movement of the tongue during swallowing.
It assists in propelling the food towards the throat by producing rippling motions

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

23. What was the time interval that you recorded between the first and second sound
8-20 seconds









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12 years ago
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