BIOL2930 17 S2 LAB 10 DIGESTIVE ENZYMES POST-LAB [Compatibility Mode] Mailings R
ID: 3516448 • Letter: B
Question
BIOL2930 17 S2 LAB 10 DIGESTIVE ENZYMES POST-LAB [Compatibility Mode] Mailings Review View NormalHeading 1No SpacingHeading 2 Experiment #2: You conduct an experiment to investigate the effects of pH on the digestion of protein. After incubating your samples for 1 hour, you use Biuret's reagent to determine whether digestion occurred. Results from this experiment are presented in Table 2 below. Use the data in Table 2 to answer question 3. This is similar to what you did in lab. Refer to your notes. Table 2: Experiment #2 Results Biuret's test Pink Purple Test Tube # Test Tube Contents Pepsin + albumin + HCI Pepsin +albumin + NaOH rned pink and Tube 2 turned purple. You must comment on the effect (3ptsl Explain why Tube 1 tu of pH differences of the experimental setup. 3.Explanation / Answer
Pepsin is a hydrolytic enzyme that cleaves peptide bonds after phenylalanine, tryptophan, and tyrosine. It is stable in acidic conditions and gets irreversibly damaged at pH > 7.0.
So, pepsin is functional in the test tube-1 as it contains HCl.
Pepsin is non-functional in the basic pH. So, there will not be any bond cleavage in test tube-2 as it contains NaOH.
Biuret test detects the presence of peptide bonds. It is a clear blue colored solution which turns violet/purple in the presence of peptide bonds.
Since there was no peptide bond cleavage in test tube-2, biuret reagent produces purple/violet color.
When the peptides are very short, the solution turns to the pink color. In test tube-1, acid hydrolysis of the protein produces small peptides. Hence it turns Biuret reagent pink.
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