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UMUC Biology 102/103
Lab2:The Chemistry of Life
INSTRUCTIONS:
·
On your own and
without assistance, complete thisLab 2Answer Sheet
electronically and submit it via theAssignments Folder by the date listed in theCourse Schedule (underSyllabus).
·
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 2
Answer 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
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?
Given
when 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.
Which of the following is not an organic
molecule; Methane (CH4), Fructose (C6H12O6),
Ethanol (C6H12O), or Ammonia (NH3)? How
do you know?
Experiment
1: Testing for Proteins
Data Tables and Post-Lab Assessment
Table 1: A Priori Predictions
Table
1: A Priori Predictions
Sample
Will
There be Protein Present?
Initial
Color
Final
Color
1 – Albumin Solution
2 – Gelatin Solution
3 – Glucose
4 – Water
5 – Unknown
Table 2: Testing for Proteins Results
Table
2: Testing for Proteins Results
Sample
Initial
Color
Initial
Color
Is
Protein Present?
1 – Albumin Solution
2 – Gelatin Solution
3 – Glucose
4 – Water
5 – Unknown
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.
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.
3. Identify two regions which
proteins are vital components in the human body. Why are they important to
these regions?
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.
Experiment
2: Testing for Reducing Sugars
Data Tables and Post-Lab Assessment
Table 3:Testing for Reducing Sugars Results
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
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.
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)?
3.
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
Table
4: pH Values of Common Household Substances
Substance
pH Prediction
pH Test Strip Color
Acetic Acid (Vinegar)
Sodium Bicarbonate Solution (Baking
Soda)
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.
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