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Need a little help on PhysioEx 9.0, Exercises 8, Chemical and physical processes of digestion

The following questions refer to Activity 2: Exploring Amylase Substrate Specificity.

1. Describe why the results in tube 1 and tube 2 are the same.
2. Describe the result in tube 3. How well did the results compare with your prediction?
3. Describe the usual substrate for peptidase.
4. Explain how bacteria can aid in digestion.

The following questions refer to Activity 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.
2. Was your prediction correct aboutthe optimal pH for pepsin activity? Discuss the physiological correlation behind your results.
3. What do you think would happen if you reduced the incubation time to 30 minutes for tube 5?


The following questions refer to Activity 4: Assessing Lipase Digestion of Fat.
1. Describe the activity of lipase with and without the addition of bile salts. Refer to Chart 4 for pH values.
2. Is the activity of bile a chemical or a physical process? Explain.
3. What pH resulted in the maximum pancreatic lipase activity? How does this optimal pH correlate to the enzyme’s location in the body?
4. Explain whether or not we can determine fat hydrolysis in tube 5. Why or why not?

Any help would be greatly appreciated

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Are you sure these are for answers for PhysioEx 9.0 ???  The questions are different then 8.0.

Activity 2: Exploring Amylase Substrate Specificity.
1. Describe why the results in tube 1 and tube 2 are the same. Is not a yes or no question.

you have 4 answers for activity 3 and there is only 3 questions PhysioEx 9.0  :s

I appreciate the quick response but I'm a little skeptical of the answers, and I will continue to do the exercises. Checking back to confirm what answers I come up with the ones you have provided.  8-)

Duddy is correct, my version of PhysioEx 9 is the same.

What are you talking about...look at what I posted, ok let's break this down.

PhysioEx 9.0, Exercises 8, Chemical and physical processes of digestion

The following questions refer to Activity 2: Exploring Amylase Substrate Specificity.

1. Describe why the results in tube 1 and tube 2 are the same. This is not a yes or no question!

1. No, amylase doesn't use cellulose as a substrate. Starch is the substrate for amylase. ???

2. Describe the result in tube 3. How well did the results compare with your prediction? Tube 3 is Amylase ans Cellulose....Not Bacteria

2. The bacteria were able to digest the cellulose because they produce the enzyme, cellulase.???

3. Describe the usual substrate for peptidase. What is the USUAL   substrate for peptides?

3. The peptidase had no effect on the starch because the substrate for peptidase is peptides and proteins.

4. Explain how bacteria can aid in digestion.  EXPLAIN....so bacteria....is the smallest subunit aiding in digestion???

4. The smallest subunit that starch can be broken down into is glucose.

The following questions refer to Activity 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. What glands, Gastric juice?????

1. The optimum pH matches the pH secreted by gastric glands. Gastric juice is also about pH 2.

2. Was your prediction correct about the optimal pH for pepsin activity? Discuss the physiological correlation behind your results. This looks good!!!

2. Since the pH of the mouth is closer to neutrality, you would expect pepsin to be slightly active but not as
active as it is in the stomach at pH 2. looks goods

3. What do you think would happen if you reduced the incubation time to 30 minutes for tube 5? There not asking about subunit products.

3. The subunit products of digestion are peptides and amino acids.?????

There is no question 4, in PhysioEx 9.0, Exercise 8 this sends up a red flag.

4. The smallest subunit that starch can be broken down into is glucose.????? again no question 4...


Do you see what I mean?

The Review sheet for Exercise 8 is on page 127 and 128,   

ISBN-13: 978-0-321-81557-6   OR    ISBN-10 0-321-81557-2

just check the book out and see if your using the right one.....please.

Homer: I noticed that too, but Duddy posted the answers that correspond to the activities you needed help on. Whether or not they are in the correct order, that's up for debate.

Sorry about the confusion, but here's the part...

I think I know, were I went wrong. I need the Review Sheet questions. Maybe this will help?

The substrate of amylase is animal starch and the product is maltose and glucose.


The boiling denatured the enzyme and inactivated it as predicted. The freezing has no effect on the enzyme.

You mean these? :thi:

duddy, I think our books are different. My activity questions are not the same as yours.

Were all the exercise 8 review questions posted?

this was all very much confusing  ???

thanks for the help guys! It helped me understand a little more  ;)

The answers were out of order but I figured it out. Thanks!

Here's for activity 1! hope it helps!! :)

uld you happen to have the answers for physio 9 exercise 8 activity 1 activity questions?

2.  what is the purpose for including tube 3 and what can you conclude from the result?

3.  describe how you determined the optimal ph for amylase activity?

4.  judging from what you learned inthis activity suggest a reason why salivary amylase wold be much less active in the stomach?

Please start a new topic... will answer #2 for now.

The purpose of including Tube #3 is to observe the activity of the enzyme at neutral pH. The enzyme is very active at this pH.

This was alot of help, re-assured all my answers...thanks :)

Huge help, thanks!

1. Explain why you can't fully test the lipase activity in tube 5.
Your answer:
because lipase is enzyme that has optimum pH at 9.0 which is alkali, but in tube 5 the pH is acidic at pH 2.0. As enzymes
are highly sensitive and specific for lipase is react at pH 9.0. the condition of pH 2.0 buffer inhibits its enzymatic reaction.
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.
Your answer:
tube 6 have the highest lipase activity. tube 6 has solution that contains lipase, vegetable oil , bile salt and pH 9.0 buffer. to
breakdown lipid in this experiment is the vegetable oil, it must first coated with bile salt to break the fat globules into small
droplets so that they can enter the membrane. next the bile salts are negatively charged, making the droplets repels each
other (seperated with each other) and form an emulsion. emulsion droplet, which are seperated, give fat digesting enzyme
lipase a greater surface area to act on. so the digestion of lipid is completed as the end product is acidic which is fatty acis
the pH decrease from pH 9.00 to pH 8.97.
3. Explain why pancreatic lipase would be active in both the mouth and the pancreas.
Your answer:
pancreatic lipase is produced in the pancreas and is secreted into the intestines. Our mouths have salivary lipase, which is a
form of lipase formed in the salivary glands and secreted into the mouth.The salivary glands produce an enzyme called
lingual lipase which helps to break down fat. However, this enzyme operates best at pH 4.5 - 5.4 so it is not very active until
it reaches the stomach.
4. Describe the process of bile emulsification of lipids and how it improves lipase activity.
Your answer:
-for fat digestion, a process called emulsification happens in the small intestine. this process functions in accelerating fat
digestion.
-fats are triglyceride (not water-soluble ) . In the chyme , they will clump to form fat globules.
-As the fat globules move in the intestinal wall, the movement of the muscle layers breaks apart the fat globules into small
droplets that coated with bile salts.
-bile salts are negatively charged, making the droplets repels each other (seperated with each other) and form an emulsion
- emulsion droplet, which are seperated, give fat digesting enzyme lipase a greater surface area to act on
-by the time peristalsis has moved the chyme mixture through the duodenum, chemical digestion of our meal is just about to
complete.

My physio q's and answers are not in the same order as previous stated answers. I have the first questions on activity 3 as describe the effect that boiling effect hod on pepsin and how u could tell that it have that effect. answer previously stated dont match up.

Thank you! This was so helpful.  :)