The Chemistry of Life

To conduct your laboratory exercises, use the Laboratory Manual that is available in the “Content” section of the Leo classroom or at the eScience Labs Student Portal. Laboratory exercises on your CD are not be updated. On your own and without assistance, complete this Lab 2 Answer Form electronically and submit it via the Assignments Folder by the date listed on your Course Schedule (under Syllabus). Type your answers into the shaded boxes provided after the questions. The boxes will expand as you type.

When necessary, insert graphs prepared in Excel, or image files (scans, photos, etc.) into the clear boxes provided. Save your Lab 2 Answer Form in the following format: LastName – Bio 102 Lab – Lab 2 Answer Form (e.g., Largen – Bio 102 Lab – Lab 2 Answer Form). You should submit your document in a Word (.doc or .docx) or Rich Text Format (.rtf) for best compatibility. Please note that this answer form also serves as a grading rubric. The grading information for each question is provided in red text in parentheses following each question/graph/table, etc. Skipping a requested question, part of a question, table, graph, etc., will result in the designated amount of percentage points being deducted from the grade for this lab answer form.

Experiment 1: Testing for Proteins (49 points)
Data Tables and Post-Lab Assessment
Table 1: A Priori Predictions
(1 points/cell = 15 points)

Sample
Will There Be Protein Present?
Initial Color
Final Color
1. Albumin Solution
YES
WHITE CLEAR
VIOLET
2. Gelatin Solution
YES
LIGHT YELLOW ALMOST CLEAR
LIGHT BLUE
3. Glucose
YES
CLEAR
LIGHT BLUE
4. Water
NO
CLEAR
SAME AS INITIAL
5. Unknown
NO
CLOUDY WHITE
SAME AS INITIAL

Table 2: Testing for Proteins Results
(1 points/cell = 15 points)

Sample
Initial Color
Final Color
Is Protein Present?
1. Albumin Solution
WHITE CLEAR
VIOLET
YES
2. Gelatin Solution
LIGHT YELLOW ALMOST CLEAR (LOOKS LIKE APPLE JUICE)
LIGHT VIOLET
YES
3. Glucose
CLEAR
LIGHT BLUE
NO
4. Water
CLEAR
LIGHT BLUE
NO
5. Unknown
CLOUDY WHITE
CLOUDY LIGHT BLUE
NO

Post-Lab Questions
1 How did your a priori predictions from Table 1 compare to your actual results in Table 2? If there were any inconsistencies, explain why this occurred. (4 points) I did not predict every solution correctly but was very close. I was predicting glucose to contain protein after the experiment I realize now why it makes sense that it does not. There were some inconsistencies such as human error in getting exactly 5mL using the pipettes.

2 Identify the positive and negative controls used in this experiment. Explain how each of these controls are used, and why they are necessary to validate the experimental results. (Identify=2 points, explain=2 points, why=2 points, for a total of 6 points) The positive control is the substance in which you know would cause an effect for example in this case the egg white is the positive and the negative is the water. Both substance could be predicted before the experiment giving people an idea of what they are searching for.

3 Identify two regions in which proteins are vital components in the human body. Why are they important to these regions? (Identify=2 points, why=2 points, for a total of 4 points) Proteins is important to the muscle region and ligaments. Protein is the building blocks for these two regions. The body does not build protein or store it, and that is why when the body consumes it these regions take a large amount of it. The body uses protein to build and repair tissues.

4 Diet and nutrition are closely linked to the study of biomolecules. Describe one method by which you could monitor your food intake to ensure the cells in your body have the materials necessary to function. (5 points) One method to monitor food intake is logging in what our daily intake is. If we know what we are eating daily and looking at the content we could know what to stay away from. Also, it is a positive indication of what the body needs.

Experiment 2: Testing for Reducing Sugars (28 points)
Data Tables and Post-Lab Assessment
Table 3: Testing for Reducing Sugars Results
(1 points/cell = 15 points)

Sample
Initial Color
Final Color
Reducing Sugar Present
1 – Potato
LIGHT CLOUDY MUSTARD
DARK YELLOW
YES
2 – Onion
CLEAR
YELLOW
YES
3 – Glucose Solution
CLEAR
YELLOW
YES
4 – Water
CLEAR
LIGHT BLUE
NO
5 – Unknown
FOGGY WHITE
DARK YELLOW
YES

Post-Lab Questions
1. Write a statement to explain the molecular composition of the unknown solution based on the results obtained during testing with each reagent. (5 points) The unknown substance does not contain protein BUT it does contain sugar. Meaning this substance is a sort of carbohydrate.

2. What can you conclude about the molecular make-up of potatoes and onions based on the test you performed? Why might these foods contain these substance(s)? (What=2 points, why=2 points, for a total of 4 points) Both potatoes and onions contain some sugar in it. These foods might contain these substance to sustain the well-being from going good to bad. These sugars contained in both potatoes and onions are naturally formed.

3. What results would you expect if you tested ribose, a monosaccharide, with Benedict’s solution? Biuret solution? (Benedict’s=2 points, biuret=2 points, for a total of 4 points) The ribose may change to red, yellow, or green to represent the monosaccharide. Considering ribose does not contain protein the biuret solution would have no effect.

Experiment 3: What Household Substances are Acidic or Basic? (23 points)

Data Tables and Post-Lab Assessment
Table 4: pH Values of Common Household Substances
(1 point/cell + ½ point/substance name = 14 points)

Substance
pH Prediction
pH Value Indicated by Test Strip Color
Acetic Acid (Vinegar)
3
5
Sodium Bicarbonate Solution (Baking Soda)
8
7
LEMON JUICE
3
4
DISHWASHER SOAP
9
6
FLOOR CLEANER
6
6
OVEN CLEANER
10
12

Post-Lab Questions
1 What is the purpose of determining the pH of the acetic acid and the sodium bicarbonate solution before testing the other household substances? (2 points) Acid and basic substance react to each other, starting with the strong substance first would avoid complication in the rest of the substance.

2 Compare and contrast acids and bases in terms of their H+ ion and OH- ion concentrations. (3 points) The more acidic a substance the more hydrogen ions in the solution. Fewer hydrogen ions the more basic the solution. Both acids and bases that are balanced in terms of their H+ ion and OH- ion represents neutral solutions.

3 Name two acids and two bases you often use. (1 points for each acid, 1 points for each base, for a total of 4 points) Two acidic substance I use often is lemon juice and orange juice. Two basic substance I use often is oven cleaner and bleach.