lab assignment

Sigchi4life
Category:
Biology
Price: $80 USD

Question description

Lesson 13: Laboratory: Human Digestion Actions 1

Have you ever wondered what your breakfast eggs look like after being churned around in your stomach for a few hours? Well, here's your chance to find out. Follow the directions in the lab to "digest" hard-boiled eggs.

Lesson Objectives

  • Explain digestion and waste removal in representative organisms.

  • Describe the process of digestion in a human, citing examples from anatomy.

  • Know the individual functions and sites of secretion of digestive enzymes.

  • Explain digestion and waste removal in representative organisms.

  • Describe the process of digestion in a human, citing examples from anatomy.

  • Know the individual functions and sites of secretion of digestive enzymes.

    PREPARE

    Approximate lesson time is 60 minutes.

    Student Materials

  • Laboratory Guidelines (PDF)

    LEARN

    Activity 1: Human Digestion Actions 1 (ONLINE)

    Instructions

    As you read through the lesson online, use the space below to take notes.

    You can simulate stomach digestion in a lab.

    Investigate the properties of human digestion in a virtual laboratory setting.

    Activity 2: Human Digestion Actions 1 (ONLINE)

    Instructions

    Procedure

    Follow the procedure to conduct the lab.

    Part A: Introduction

    1. Open the Human Digestion Virtual Lab.

    2. Click the View the Tutorial button.

    3. Complete the tutorial to learn how to use the materials in the lab.

    4. When you have finished the tutorial, click the home button, reset the lab, and click the Begin the Lab button. Then continue with Part B.

    5. If you have not yet printed the Lab Report for this lesson, do so now.

    Part B: Milk Digestion

    1. Using the pipette labeled “Milk,” place one pipette full of milk in each of the four test tubes in the rack on the left side of the lab bench.

    2. Fill each test tube with 2.5 mL, or one dropper-full, of each liquid as indicated in the table.

 Test tube number

 Liquid 1

 Liquid 2

 Liquid 3

 1

 milk

 water

 none

 2

 milk

 hydrochloric acid

 none

 3

 milk

 lactase

 none

 4

 milk

 lactase

 hydrochloric acid

When milk is digested, lactose, a sugar, is split. This releases two smaller sugars, glucose and galactose. The glucose test strip indicates the presence of sugar. Do not use these strips yet.

3.  Write your predictions about what will happen with regard to the presence of glucose after the test is finished in the Milk Digestion data table.


Part C: Protein Digestion

1.  Mince the egg.

2.  Using the spoon, place one spoonful of egg white in each of the six test tubes in the rack on the right side of the lab bench.

3. Fill each test tube with 2.5 mL, or one dropper-full, of each solution as indicated in the table.

 Test tube number

  Substance Added

1.protein

 10 mL water

2.protein

 10 mL pepsin

3.protein

 10 mL hydrochloric acid

4.protein

 10 mL sodium bicarbonate

5. protein

 5 mL pepsin + 5 mL sodium  bicarbonate

6. protein

 5 mL pepsin + 5 mL hydrochloric acid

4. Using the forceps, pick up a pH test strip and determine the pH for each protein test tube. Record your results in the Protein Digestion data table.

5. In the Predictions column of the Protein Digestion data table, write a prediction about which solution you think will digest the egg white the most completely. Explain your reasoning.

Part D: Set the Timer

1. Place a stopper on top of all test tubes.

2. Once all the test tubes have been covered, click Start on the timer.

3. Write down the code you are given exactly, or copy and paste it onto a text file that you can easily retrieve.

4. For the reactions to take place, wait an entire 48 hours. After 48 hours have passed, enter the code in the space provided on the opening screen. The program will bring you back to your lab where the reactions will have taken place.

Part E: Record the Results

1. Observe the results of the milk digestion test tubes. Record your observations in the Milk Digestion data table.

Remember: When milk is digested, lactose is split, releasing glucose and galactose. The glucose test strip indicates the presence of these sugars.

2. Use the forceps to test for the presence of glucose in each milk digestion test tube, and record your results in the Milk Digestion data table.

3. Observe the results of the protein digestion test tubes. Record your observations in the Protein Digestion data table.

Data Tables

Milk Digestion

 Test tube  
 number

 Prediction

 Test strip results

 Was the milk  
 digested?

 1

 2

 3

 4

Protein Digestion

  Test tube

 number

 Prediction

 Description of result

 1. protein + water

 

 2. protein + pepsin


 


 3. protein + acid

 

 

 4. protein + base

 


 


 5. protein + pepsin + base

 

 6. protein + pepsin + acid

 


Tutor Answer

(Top Tutor) Daniel C.
(997)
School: Cornell University
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