Chemistry & Biological Macromolecule Name: ______

Online LabsDate: ______Block: ____

Part I – Basic Chemistry (pH Lab Online)

Use this website to complete Part I

Click on the EXPLORE button (USE LINKS AT THE BOTTOM OF THE SCREEN). When the next screen appears, you will have the opportunity to test the acidity or alkalinity (how much base) of 12 various substances. To test a substance, click on the substance and view the changes.

Substance / Acid/Base & pH indicator number / Color Change of Liquid / Color Change of Litmus Paper
Lemon juice
Baking soda
Aspirin
Ammonia
Milk of magnesia
Lava soap
Borax
Water
Lemon soap
Vinegar
Tonic water
Liquid plumber

After completing the table, click on the EXPLAIN button at the bottom of the page. Use the information in the EXPLAIN section to answer the following questions.

  1. What parts make up each molecule of water?
  2. What is the chemical formula for water?
  3. When an acid is poured into water, what does the acid lose?
  4. When a base is poured into water, what does the base lose?

Part II: Biological Macromolecules Online Lab

Use this website to complete Part II

  1. Why would a scientist use a negative control in his/her experiment?
  2. Complete the table below by clicking the appropriate boxes on the website.

Test For: / Solution Used: / Color of Negative Control after Test / Color of Positive Control after Test
Reducing Sugar
Starch
Protein
Lipid

Test of Unknown 1:

  1. Which of the test tubes shows positive test results?
  2. What macromolecule(s) is/are present in Unknown 1?

Test of Unknown 2:

  1. Which of the test tubes shows positive test results?
  2. What macromolecule(s) is/are present in Unknown 2?

Test of Unknown 3:

  1. Which of the test tubes shows positive test results?
  2. What macromolecule(s) is/are present in Unknown 3?

Part III: Online Enzyme Lab Simulation

Use this website to complete Part III

Purpose/Background: In this investigation, you will determine the effects of substrate concentration and pH on the initial rate of an enzyme-catalyzed reaction. You will be testing two separate questions/hypotheses during this virtual simulation. Each simulated test tube contains the same enzyme solution. You will adjust the pH levels or the amount of substrate added to collect the necessary data. The initial reaction rate is given as the number of product molecules formed during the first minute for each test tube.

Procedure:

  • pH level is adjusted by clicking the up or down arrows below the corresponding test tube
  • to add substrate, click and drag the weighing paper to the appropriate test tube
  • for all trials, assume the enzyme concentration in each test tube is constant

Question: How does pH affect enzyme controlled reactions?

  1. Adjust the pH level of test tube 1 to 3, test tube 2 to 5, test tube 3 to 7, test tube 4 to 9, and test tube 5 to 11. The test tubes should be reset to the pH values for each trial outlined below.
  2. Add 0.5 g of substrate to each of the test tubes.
  3. Click on the computer screen to observe the calculated data. Record the data in Data Table 2: pH Level Results in the column 0.5 g.
  4. Click the RESET button.
  5. Adjust the pH levels as stated in step 1.
  6. Add 2.0 g substrate to each of the test tubes.
  7. Click on the computer screen and record your data in the appropriate column.
  8. Click the RESET button.
  9. Repeat steps 1 – 3 using 8.0 g substrate.

Data Table 2: pH Level Results

Test Tube Number / pH Level / Number of Molecules of Product Formed per
Minute (x106) at 0.5 g / Number of Molecules of Product Formed per
Minute (x106) at 2.0 g / Number of Molecules of Product Formed per Minute (x106) at 8.0 g
1 / 3
2 / 5
3 / 7
4 / 9
5 / 11

Graphing

Create one graph. Your graph can be created in Excel or hand drawn, but must have all data shown. Graphs must be neat, axes must be labeled with appropriate values, titles included, and a legend/key provided.

Conclusion/Summary

  1. What is the function of an enzyme?
  2. What is a substrate?
  3. What happens to the enzyme and the substrate during a chemical reaction?
  4. What does it mean by enzymes being specific?
  5. What does catalase do? Use the terms substrate and product in your response.
  6. How can you tell that catalase has been added to hydrogen peroxide?
  7. Why is the active site site specific for only one type of substrate?
  8. What happens when a substrate with a different shape from the active site tries to enter the active site?
  9. What does your data indicate that the optimum pH level for this enzyme is?