Sprint LTE 8:47 AM a instructure-uploads.s3.amazonaws.com Experiment # 1 : You c

Question

Sprint LTE 8:47 AM a instructure-uploads.s3.amazonaws.com Experiment # 1 : You conduct an experiment to investigate the effects of temperature and pH on the action of amylase, an enzyme that digests carbohydrates. After incubating your samples for 1 hour, you use iodine to test for the presence of starch and Benedict's reagent to test for the presence of digested product. Results from this experiment are presented in Table1 below. Use the data below to answer questions 1 & 2. This is similar to what you did in lab. Refer to your notes Table 1: Experiment 1 Results Test Tube # Test Tube Contents lodine Test Benedict's Test No change (blue) No change (blue) Starch water black Starch +saliva mix (amylase) HCI Purple-black Starch boiled saliva mix (amylase) Purple-black No change (brown) Starch+saliva (amylase) Red 1. [3pts] Based on the results in Table 1, which tube has the highest amount of digested product? Explain what pieces of evidence you have. 2. a. [2pts] Based on the results in Table 1, which tube has partial digestion? Explain what pieces of evidence you have. b. [2pts] Why wasn't there complete digestion in this tube?

Explanation / Answer

The Iodine test detects the presence of the polymer amylose ( which is an indication that starch has not hydrolyzed, and remains intact). The brownish coloured iodine complex turns purplish-black in the presence of starch.

Benedict's reagent is used to determine the presence of free reducing sugars like glucose and fructose. It turns from blue to dark red in the presence of reducing sugars.

Now , to analyse different conditions -

1. Non digested starch = Indicates intact starch ( no free reducing sugars)

2. Digested starch = Starch which is broken into free sugars ( reducing sugars present)

Solution 1: Tube no 4

A completely digested product is one where there is 100% free sugars, and no amount of starch. This means the tube should be positive for Benedict's test, and negative for iodine test. Since such an observation is seen in Tube no.4, it indicates highest digested product. Possible explanation is that this tube contains enzyme amylase that has not been tampered by acid or by heat.

Solution 2: Tube 3

Partial digestion would indicate the starch has not been fully hydrolyzed into free sugars. Therefore, the tube would contain both starch and free sugars. The observation would be that this tube would show positive results for both iodine test and benedict's test. Such an observation is seen in tube no. 3
A possible explanation is that boiling inactivates some of the enzyme amylase, thereby decreasing activity.

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