Name
Date
Period
In this online investigation, you will examine foods to determine what type of predominant organic compounds
can be found in each. Make sure to read the whole paper and answer all questions.
Go to: http://www.occc.edu/biologylabs/Documents/Organic%20Compounds/Organic%20Compounds.htm
Read the introduction.
What 3 specific organic compounds will you study in this lab?
Why are we not doing any tests for nucleic acids?
How will indicators assist us in this lab?
What does the word “predominantly” mean?
How does that word influence this lab?
Since all organic substances contain carbon, can our indicators be used to detect carbon? (Explain)
If we are testing for a specific monomer in a food, what would a “positive +” or “Negative –“ outcome mean?
You’ll notice at the bottom of the pictures (once you get past the intro) you see “home” and “organic
molecules” you are not selecting those during the lab. You are clicking on the action link “add 2 ml” (example).
Start by clicking on carbohydrates.
What indicator will you be using to test for the presence of a monosaccharides?
What color will it change if they are present in the food?
Read the instructions as to what to click on next to take you through the experiment, reading each screen for
instructions and to see positive and negative reactions. (Outcomes)
Describe the positive test result and the negative test results in data table 1.
Why during these tests did we have a test tube with only water in it?
What is the indicator used for simple sugars?
What is a + and – reaction for the presences of simple sugars?
Name the actual sugar tested for in this activity.
What is the chemical relationship between a “simple sugar” and a “carbohydrate”?
Iodine is used to test for starch. Click through the demonstration to see what a positive and negative test result
for starch look like. Describe both of them on data table 1.
Why does this lab do starches with carbohydrates?
Once you are done with an organic group, it takes you back to the “home” screen. So now, click on Proteins.
Read the description of the proteins.
What is a similarity between the drawing of the protein and the one of the carbohydrate you saw earlier?
(What is one thing they share?)
What is one difference between those drawings?
What will you be using to test for proteins?
What does a positive test result look like?
On data table 1, describe a positive test result and a negative test result for proteins.
Next click on fats. Read the description of fats.
Again, what is one similarity between the molecular structure (chemistry) of the protein, fat and
carbohydrates?
What is one difference between them all?
What will you be using to test for fats?
What will it look like if there are fats in the food?
Click through the test to show the results. Describe both the positive and negative test results in data table 1.
Data Table 1: Describe what each of the results looks like.
Test
Positive Result
Negative Result
Simple Sugars
Starch
Proteins
Fats
You haven now seen what both positive and negative test results look like. You will use this information to test
various foods to see if they contain these compounds. Click on Foods. You will test all 6 of the foods shown.
As you go, record if the test shows a positive (+) or a negative (-) test results for each of the compounds in data
table 2. If you are not sure if the test is positive or negative, refer back to data table 1. And as a heads up, think
about the fact that foods are very complex! It may be possible to get multiple + results for any given food!
Data Table 2: Put a + for a positive test and a – for a negative test in each of the boxes.
Food
Potatoes
Eggs
Orange Juice
Salmon
Almonds
Milk
Simples
Sugars
Starch
Protein
Fats
Rank the above foods in order you like them, 1 being your favorite and 6 being your least favorite.
Conclusion Questions: Answer the questions in complete sentences. You may use the information from the lab,
and your notes to answer them.
1) What foods contained protein?
2) Why is it important for our bodies to eat protein?
3) What is the difference between a monomer and a polymer?
4) Which monomers did you test for?
5) Which polymers did you test for?
6) What foods tested positive for carbohydrates?
7) List the 3 items that would all be classified as a “carbohydrate”.
8) What is the actual chemical difference between those 3 items listed above?
9) What do all of the compounds we tested for today have in common?
10) Give four reasons why C is such an important life element.
11) Draw the valence for carbon. On your diagram be sure to include the mass, number of; protons, electrons
and neutrons found on the item.
12) For carbon (look at your drawing to assist) we say it can either be an anion or cation after an ionic bond. (It
is not more likely to be one or the other). Explain this using carbon’s valence.
13) Using rules from class, justify this statement “carbon polymers are covalently bonded molecules”.
14) Lipids can be
meaning they are full of hydrogen atoms or they can be
meaning they are not full of H atoms.
15) Think back to the cell membrane and knowing what you now know would the cell membrane test positive
or negative for Sudan IV? Explain why o why not.
16) Where do we store the directions for how to make a protein?
17) What is the organelle that makes the protein?
18) What organic compound did we not test for in this lab? Why didn’t we?
19) Fill in the table below:
Type of
Functional Group
molecule
Function
Monomer
Example
Carbohydrate
Lipid
Protein
Nucleic acid
21. Identify these organic compounds based on their chemistry. Circle the defining functional group.
20) Colored diagrams: Your job here is to draw AND color the basic building blocks of life. Follow the instructions
below and be sure to draw neatly and clearly for points! Don’t forget a color key and labels!
A) Assign a different color and shape to each of the main elements found in organic
Color&
compounds: C,O,H,N,P, D(deoxyribose) and R (Ribose) (You may use “light blue”
Element
Shape
and “dark blue” if you run short of colors.)
C
B) For each organic compound listed in the boxes below, you are to draw and color
appropriate, accurate models to represent their chemistry.
O
H
N
Simple Carbohydrate
disaccharide
Complex carbohydrate
P
D
(deoxyribose)
R
(ribose)
Protein
Regular fat
phospholipid
Sterol
DNA
RNA