Label four clean test tubes I to 4 Using the designated grad

Label four clean test tubes (I to 4). Using the designated graduated transfer pipets, add 1 ml of the experimental solutions listed in Table 3.2 to the test tubes according to their numbers. Then add five drops of beret reagent to the tubes, swirling to mix. The reaction is almost immediate. Record your observations in Table 3.2. From your test results, conclude if a protein is present (+) or absent (-). Enter your conclusions in Table 3.2. Pepsin is an enzyme. Enzymes are composed of what type of organic molecule? _____ According to your results, is starch a protein? _____ Which of the four tubes is the negative control sample? ______ Why? _____ Why do experimental procedures include control samples? _____ If your results are not as expected, inform your instructor, who will advise you how to proceed.

Solution

A) enzymes are nothing but the proteins only which is made up of different amino acids which are joined together by the presence of the peptide bond between the two amino acids...!!

B) no starch is not a protein it is carbohydrates which is made up of glucose as a repeating units..!!

C) negative control is that in which every reagents is present EXCEPT the sample which gives the test. According to this, the first tube which contains only the distilled water in it is a negative test because in that tube no protein or enzymes is present hence it gives a negative results hence it can be used as a negative control sample.

D) control sample are very important in an experiment.

Positive control helps us to infer the correct results. By comparing with the positive results we can come to the conclusion that the test sample gave the correct inference..

Negative control helps us to make sure that the whether test sample do not contain the desired components that we are checking by comparing with the results..