Maryland BIO 103 – Lab 2, The Chemistry of Life
Your Full Name:
UMUC Biology 102/103
Lab 2: The Chemistry of Life
INSTRUCTIONS:
• On your
own and without assistance, complete this Lab 2Answer Sheet electronically and
submit it via the Assignments Folder by the date listed intheCourse Schedule
(under Syllabus).
• To
conduct your laboratory exercises, use the Laboratory Manual located under
Course Content. Read the introduction and the directions for each
exercise/experiment carefully before completing the exercises/experiments and
answering the questions.
• Save your
Lab 2Answer Sheet in the following format:
LastName_Lab2 (e.g., Smith_Lab2).
• You
should submit your document as a Word (.doc or .docx) or Rich Text Format
(.rtf) file for best compatibility.
?
Pre-Lab Questions
1. Nitrogen
fixation is a natural process by which inert or unreactive forms of nitrogen
are transformed into usable nitrogen. Why is this process important to life?
2. Given
what you have learned about the hydrogen bonding shared between nucleic acids
in DNA, which pair is more stable under increasing heat: adenine and thymine,
or cytosine and guanine? Explain why.
3. Which of
the following is not an organic molecule; Methane (CH4), Fructose(C6H12O6),
Rosane (C20H36), or Ammonia (NH3)? How do you know?
?
Experiment 1: Testing for Proteins
Data Tables and Post-Lab Assessment
Table 1: A Priori Predictions
Sample Initial Color Final Color Is Protein Present?
1. Albumin Solution
2. Gelatin Solution
3. Glucose
4. Water
5. Unknown
Sample Initial Color Final Color Is Protein Present?
1. Albumin Solution
2. Gelatin Solution
3. Glucose
4. Water
5. Unknown
Table 2: Testing for Proteins Results
Take a picture of your results. Include a note with your
name and date on an index card in the picture. Insert picture here:
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.
2. 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.
3. 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.
4. Identify
two regions which proteins are vital components in the human body. Why are they
important to these regions?
5. 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.
?
Experiment 2: Testing for Reducing Sugars
Data Tables and Post-Lab Assessment
Table 3: Testing for Reducing Sugars Results
Sample Initial Color Final Color
Reducing Sugar Present
1 – Potato
2 – Onion
3 – Glucose Solution
4 – Water
5 – Unknown
Take a picture of your results. Include a note with your
name and date on an index card in the picture. Insert picture here:
Post-Lab Questions
1. What can
you conclude about the molecular make-up of potatoes and onions based on the
two tests you performed? Why might these foods contain these substance(s)?
2. What
results would you expect if you tested ribose, a monosaccharide, with
Benedict’s solution? Biuret solution?
Experiment 3: What Household Substances are Acidic or Basic?
Data Tables and Post-Lab Assessment
Table 4: pH Values of Common Household Substances
Substance
pH Prediction
Test Strip Color and pH
Acetic Acid (Vinegar)
Sodium Bicarbonate Solution (Baking Soda)
Take a picture of your results. Include a note with your
name and date on an index card in the picture. Insert picture here:
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. Compare
and contrast acids and bases in terms of their H+ ion and OH- ion
concentrations.
3. Name two
acids and two bases you often use.
