Explain why a positive Benedict\'s test indicates the enzymatic hydrolysis of st

Question

Explain why a positive Benedict's test indicates the enzymatic hydrolysis of starch. 5 mL of starch was mixed with 5 mL of an amylase solution that had been boiled for 1 hour. The resulting solution was incubated in a 37degree C water bath for 1 hour. At the end of the incubation, a portion of the mixture was tested with IKI. It turned a blue-black color. A Benedict's lest was also performed on the remainder of the mixture. The result was negative. What could explain these results? Compare the rate of enzymatic hydrolysis of the protein in the ice bath versus the warm water bath. If there was a difference, explain the difference. Using results from your lab. explain why pepsin is expected to function well in the stomach but not in the small intestine. Define emulsification. Is bile sal, necessary for enzymatic hydrolysis of triglycendes? Explain your answer.

Explanation / Answer

1.   Benedict's solution contains Copper, which can accept electrons from reducing sugars and consequently change color. A positive Benedict's sugar test will produce an orange to brick-red color. Reducing sugars have either a free aldehyde functional group or a free ketone functional group as part of their molecular structure; starches and other polysaccharides lack these functional groups. If Benedict's test changes color ( pos. reaction ) polysaccharides must be enzymatic hydrolyzed.

5.    Emulsification is the breakdown of large fat globule into small, uniformly distributed particle and it is accomplished by bile acids in the small intestine.

Bile salt emulsify the large fat molecule to smaller droplets so that pancreatic lipase can hydrolyse the triglycerides.

Bile salts help in combination of lipase with two molecule of small protein to form colipase that enhance lipase activity

4.     Pepsin secreted by chief cell and secreted as pepsinogen as inactive form , at low PH its activity is greatest and decrease in high PH , Protein breakdown to smaller peptide fregments by breaking of peptide bonds and stomach is having acidic enviroment so activity increased in stomach and decrease in intestine

Polypeptide + H20   PEPSIN ANDAcidic environment(HCl) >>> polypeptide fragements

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