The questions that needs to be answered is in the file itself.
These are the results of my Lab Report.
Please watch the following video https://www.youtube.com/watch?v=wJykz_Eg1G4&t=83s (you may stop at 3:00 minutes) and answer the following questions according to the video.
Q1. Should a healthy adult excrete sugar into urine after eating a lot of sugar? No they shouldn’t
Q2. How long did the person in the video wait before reading the result of the test strip? The person should wait 2 mins but on the video he only waited for a few seconds
1. The following chart was used to measure the glucose content of solutions in this part of the experiment:
2. A boiling water bath and ice water bath were prepared in separate 250-mL beakers.
3. The glucose content of a 2% sucrose solution was measured using a Diastix dip stick: turquoise color/negative for glucose.
4. Approximately 2 mL of the 2% sucrose solution was placed into 3 different test tubes. 5 drops of 3 M HCl was added to each test tube. One test tube was immediately placed into the boiling water bath; another was immediately placed in the ice bath; the last was left at room temperature.
5. The glucose content of all 3 solutions was measured at 30 seconds. The results are shown in Table 1.
Table 1. Diastix test results at 30 seconds
Diastix test color glucose concentration (mg/dL)
ice bath (0 degrees C) turquoise 0
room temperature (23 degrees C) medium green 250
boiling water (100 degrees C) maroon 2000+
Q3. Please interpret the results of Table 1 in your own words. In other words, how does temperature affect the rate of sucrose hydrolysis? The temperature makes the glucose concentration higher
Q4. Please answer: What is the purpose of adding HCl to each test tube? (Please answer in your own words!) It acts as a catalyst
Joann Um-Nov 08, 2021, 5:14 AM PST
Part B. Starch Hydrolysis
Gabrielle Sanchez-Nov 08, 2021, 10:29 AM PST
Please watch the following video https://www.youtube.com/watch?v=ISf6ClTbg78 (up to 1:38 only) and answer the following questions according to the video:
Q1. What does a positive iodine test for starch look like? The positive iodine test becomes a v ery dark purple color.
Q2. What does a negative iodine test for starch look like? The negative iodine test just looks like it is yellow or orange
Q3. A solution of starch and iodine changes from ____black____ color to ______clear_____ color in the presence of amylase.
1. Three test tubes were each filled with approximately 1 mL of 1% starch solution and placed in a boiling water bath.
2. 5 drops of DI water was added to one test tube; 5 drops of 3 M HCl was added to another test tube; and 5 drops of amylase solution was added to the final test tube
3. After 30 minutes approximately 4 drops of each solution were transferred to a spot plate. 2 drops of iodine were added to each solution. The results are shown in Table 2.
Table 2. Iodine test for starch hydrolysis
Color after adding iodine solution Starch breakdown?
DI water (no catalyst) black none
3 M HCl catalyst pale black/purple partial
amylase catalyst colorless complete
Based on the color results given in Table 2 above, please fill in the last column of the table. Choose from “none,” “partial,” and “complete.”
Please watch the following video https://www.youtube.com/watch?v=bVvy2UTfcl4&t=20s and answer the following questions according to the video:
Q4. What does a negative Benedict’s test for simple sugars look like? (i.e., what is the color of Benedict’s reagent?) It is a blue liquid
Q5. What does a positive Benedict’s test for simple sugars look like? (i.e., what is the color of the solution when the reaction is complete?) its like a dark red brown
4. Approximately 2 mL of Benedict’s reagent was added to the test tubes containing HCl and amylase catalysts. The results are shown in Table 3.
Table 3. Benedict’s test on starch hydrolysis
Observation after reacting with Benedict’s reagent Amount of glucose present
DI water (no catalyst) N/A N/A
3 M HCl catalyst turquoise solution with a little orange precipitate a little
amylase catalyst orange and cloudy a lot
Based on the results given in Table 3 above, please fill in the last column of the table. Choose from “a lot” “a little,” and “none.”
Joann Um-Nov 08, 2021, 5:14 AM PST
Part C. Cellulose Hydrolysis
Gabrielle Sanchez-Nov 08, 2021, 11:00 AM PST
(I’m sorry, I couldn’t find a good video for this!)
1. Three test tubes were each filled with approximately 1 mL of 0.5% cellulose mixture and placed in a boiling water bath. (The cellulose mixture was cloudy white due to the undissolved cellulose.)
2. 5 drops of DI water was added to one test tube; 5 drops of 3 M HCl was added to another test tube; and 5 drops of amylase solution was added to the final test tube.
3. After 30 minutes approximately 4 drops of each solution were transferred to a spot plate. 2 drops of iodine were added to each solution. The results are shown in Table 4.
Table 4. Iodine test on cellulose hydrolysis
Observation after reacting with iodine reagent Amount of starch present
DI water (no catalyst) the mixture was still cloudy, but it turned brown because of the iodine reagent none
3 M HCl catalyst the mixture was still cloudy, but it turned brown because of the iodine reagent none
amylase catalyst the mixture was still cloudy, but it turned brown because of the iodine reagent none
Based on the results given in Table 4 above, please fill in the last column of the table. Choose from “a lot,” “a little,” and “none.”
Approximately 2 mL of Benedict’s reagent was added to each test tube. The results are shown in Table 5.
Table 5. Benedict’s test on cellulose hydrolysis
Observation after reacting with Benedict’s reagent Amount of glucose present
DI water (no catalyst) turquoise solution none
3 M HCl catalyst cloudy orange a lot
amylase catalyst
turquoise solution none
Based on the results given in Table 5 above, please fill in the last column of the table. Choose from “a lot,” “a little,” and “none.”
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