NAME & section #:

LAB REPORT: DIGESTION.

INTRODUCTION.

state the purpose of this exercise?

MATERIAL AND METHODS

see the lab manual.

RESULTS. (your observations of what happens during the experiments)

I: DIGESTION OF FATS

1 In the following table, tabulate class results for the digestion of milk fats by Pancreatic Lipase (Exercise A).

Table A. Digestion of milk fat by pancreatin.

Colors in test tubes during incubation
Test tube # / 0min / 15min / 30min / 45min / 1h / 1h15min / 1h30min / 1h45min / 2h
1A
2A
3A
4A

Table A (cont.)

Test tube # / Presence of fatty acids (yes/no) / Is the digestion of cream, fast, slow or is there no digestion at all?
1A
2A
3A
4A

2 Briefly describe (5 lines) the distribution of oil with and without bile salts (Exercise B).

II: DIGESTION OF CARBOHYDRATES

1 In the following tables, tabulate class results for the digestion of starch by both enzymes. Include results for iodine and Benedict's test (Exercise C).

Table B.Digestion of starch by salivary amylase.

Test tube # / pH / iodine test
(color in test tubes) / Benedict test (color in test tubes) / Presence of starch (yes/no) / Presence of reducing sugar (yes/no)
1C
2C
3C
4C

Table C.Digestion of starch by pancreatic amylase.

Test tube # / pH / iodine test / Benedict test / Presence of starch (yes/no) / Presence of reducing sugar (yes/no)
1C
2C
3C
4C

III: DIGESTION OF PROTEINS

1 In the following table, calculate class average (Exercise D).

Table D.Digestion of proteins by pepsin and trypsin.

Capillary tubes # / Solutions / Amount of egg white that has disappeared (in %) / Amount of egg white that has been digested (in %)
1 / pepsin in buffer, pH 2.0
2 / pepsin in buffer, pH 4.0
3 / pepsin in buffer, pH 6.0
4 / pepsin in buffer, pH 8.0
5 / buffer, pH 2.0
6 / buffer, pH 4.0
7 / buffer, pH 6.0
8 / buffer, pH 8.0
9 / trypsin in buffer, pH 2.0
10 / trypsin in buffer, pH 4.0
11 / trypsin in buffer, pH 6.0
12 / trypsin in buffer, pH 8.0

2 Prepare one graph showing the percent digestion of eggwhite by pepsin and trypsin. Percent of digestion should be on the Yaxis and pH on the Xaxis. Describe your results in no more than 5 lines and explain the significance of the capillary tubes full of eggwhite incubated in buffers pH 2, 4, 6 and 8.

DISCUSSION. (explanations of the events in the experiments)

Answer in the spaces provided below. Do not use extra pages.

I: DIGESTION OF FATS

Explain what is happening in each tubes of Exercise A by completing the following table.

Test tube # / Is the digestion of cream, fast, slow or is there no digestion at all? / Explain.
1A
2A
3A
4A

II: DIGESTION OF CARBOHYDRATES

Explain what is happening in each tubes of Exercise C by completing the following tables.

Amylase. (please specify which amylase you used: salivary or pancreatic?)

Test tube # / Presence of starch (yes/no) / Presence of reducing sugar (yes/no) / Explain what is happening.
1C
2C
3C
4C

III:DIGESTION OF PROTEINS

Explain the results you graphed for the digestion of proteins (Exercise D).

Explain how optimum pH is created for these enzymes in the gastrointestinal tracts (look at the location of these enzymes and the nonenzyme secretions at these locations).