I did a lab experiment about chemical digestion and absorption. We were investig

Question

I did a lab experiment about chemical digestion and absorption. We were investigating whether trypsin or pepsin would digest a piece of egg white. Also, what effect did pH have on the activity of pepsin and trypsin.

These contents were in each test tube, along with my hypothesis if the egg white would dissolve or not. If no digestion occured, the solution was blue after heating and adding biuret reagant. If some digestion occured, the solution was pink, and if a lot of digestion occured, the solution was purple.

Test tube 1: 5ml pepsin + 5ml distilled water, hypothesis: will digest, result: pink

Test tube 2: 5ml pepsin + 5 ml sodium carbonate, hypothesis: will not digest, result: pink

Test tube 3: 5ml pepsin + 5ml HCL, hypthesis: will digest, result: purple

Test tube 4: 10ml distilled water, hypothesis: will not digest, result: purple

Test tube 5: 5ml distilled water + 5ml sodium carbonate, hypothesis: will not digest, result: purple

Test tube 6: 5mL distilled water +5 ml HCL, hypothesis: will digest, result: purple

Test tube 7: 5ml trypsin+ 5ml distilled water, hypothesis: will not digest, result: pink

Test tube 8: 5ml trypsin + 5 ml sodium carbonate, hypothesis: will not digest, result: pink

Test tube 9: 5ml trypsin + 5ml HCL, hypthesis: will not digest, result: purple

Test tube 10: 10ml distilled water, hypothesis: will not digest, result: purple

Test tube 11: 5ml distilled water + 5ml sodium carbonate, hypothesis: will not digest, result: purple

Test tube 12: 5mL distilled water +5 ml HCL, hypothesis: will not digest, result: purple

Why did they all digest? I thought pepsin is only active in acidic enviornments? Also, why did they both digest in the 10ml of distilled water?

explanations are greatly appreciated, I am very confused

Explanation / Answer

The purple result shows the digestion of egg white , purple color tube with pepsine and HCL with or without water maintain acidity where the enzyme active at this pH and digest the protein . So, pepsin is active only in acidic environment.

While only in distilled water without presence of pepsine the egg white is not completely digest but due to the osmosis process distilled water enter inside the egg and swell to burst and content of egg white release in some extant showing purple color. Because egg membrane is permeable to water.

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