Name:_____________________________________
Date:____________ Period: __________
Chemistry and Identification of Carbohydrates, Lipids, and Proteins
Part A: CARBOHYDRATES
Part 1: Monosaccharides (single molecule sugars) 
Examine the structural diagrams of these three sugars (Figure 1) and answer questions 1-6.
Figure 1:
1. Name 3 elements present in the three monosaccharides above.
a. __________________________ b. __________________________ c. __________________________
2. How many atoms of carbon are present in a molecule of
a. glucose? ______
b. fructose? ______
c. galactose? _____
3. What is the chemical formula for each of the monosaccharides above? (C_ H _ O _)
a. glucose = _____________
b. fructose = ______________
c. galactose = _______________
4. What is the ratio of hydrogen atoms to oxygen atoms in a molecule of water (H2O)? 1:1
5. What is the ratio of hydrogen atoms to oxygen atoms for monosaccharides? 1:1
2:1
3:1
(circle one)
2:1 3:1 (circle one)
6. Compare the structural and chemical formulas of these monosaccharides.
a. Are they exactly the same in shape? ______
b. Do they have the same chemical formulas? ______
c. What name is given to these monosaccharides based on your answers in 6a and 6b? _________________
(HINT: check your building carbon model activity)
Part 2: Disaccharides (double molecule sugars)  Use the paper models give to you by your teacher to
complete this section.
Attach an –OH and -H to each monosaccharide (glucose and fructose).
7. Do the glucose and fructose fit together easily to form a sucrose molecule? ______
DIRECTIONS: Try removing an –OH end from one molecule and an –H end from the other to see if
that helps.
8. Does removing the –H and –OH ends allow the molecules to fit together easily? ______
9. What is the chemical formula of the new molecule after you join the removed –H and -OH: __________
10. Using chemical formulas, show how adding fructose and glucose and subtracting water produces
sucrose.
___________________________________________________________________________________
DIRECTIONS: Join two glucose molecules to form a disaccharide (double sugar) called maltose.
11. What must be removed so that the glucose molecules fit together easily? ___________
12. Using chemical formulas, show how adding glucose and glucose and subtracting water produces
maltose.
___________________________________________________________________________________
13a. How does the chemical formula for sucrose compare to maltose? ______________________________
b. Are there two times as many hydrogen atoms as oxygen atoms in a disaccharide? ______
c. How many monosaccharide molecules are needed to form one sucrose molecule? ______
d. How many monosaccharide molecules are needed to form one maltose molecule? ______
14. What type of reaction makes disaccharides like sucrose and maltose?____________________________
HINT: Use your notes
Group 3: Polysaccharide (many molecules sugars) 
STARCH, GLYCOGEN, and CELLULOSE are the three most common polysaccharides in biology. They
consist of long chains of glucose molecules joined.
DIRECTIONS: Construct a starch molecule by joining 3 glucose molecules. REMEMBER: Starch
consists of hundreds of glucose molecules so you are only constructing part of a starch molecule.
15. You probably had to remove several pieces in order to get your 3 glucose molecules to fit together
perfectly.
What new molecule(s) did these removed pieces make AND how many? ___________________
Part B: Models of Fats.
Part 1: Glycerol and Fatty Acids 
Fats are made up of glycerol and fatty acids. Examine the structural formula of glycerol (Figure 2) and
answer questions 1-4.
1. What elements are present in glycerol? ____________________________________________________
2. Are there any elements in glycerol that are NOT in
carbohydrates? ________________________________
Figure 2: Glycerol
3. What is the chemical formula for glycerol? _______________
4. Is there 2:1 ratio of hydrogen to oxygen atoms in glycerol,
like there is in carbohydrates? _________
Fatty Acids
Many different fatty acids exist, but all are similar in several ways. Butyric acid, caproic acid, and lauric
acid are examples of fatty acids. Examine the structural formulas in Figure 3 for these three molecules and
answer questions 5-8.
Figure 3:
5. What is the chemical formula for:
Lauric acid? _________________
Butyric Acid? ______________ Caproic Acid? ________________
6. Is there a definite ratio of hydrogen to oxygen atoms for all fatty acids? _____________________
7. How many oxygen atoms are present in each fatty acid? __________________________________
8. The circled region in each fatty acid is called a carboxyl group.
a. Is there a carboxyl group present in each of the fatty acids shown above? __________________
b. What elements does each carboxyl group contain? _______________________
c. Is there a carboxyl group present in glycerol? _______________
Part 2: Combining Glycerol and Fatty Acids to Form Fats
Start with 3 –H ends added to your glycerol molecule and 3 –OH ends added to each fatty acid.
9. Without removing any pieces, do glycerol and the 3 fatty acids fit together perfectly? ____________
DIRECTIONS: Remove 3 –H pieces from the glycerol molecule and 1 –OH pieces from each fatty
acid. Now join the molecules to form a fat.
10a. How many glycerol molecules are needed to make a fat molecule? ______
b. How many fatty acids are needed to form a fat molecule? ______
DIRECTIONS: Join the leftover –H and –OH ends from your models.
11. What new molecule is formed when these removed pieces are joined? __________
12. How many of these new molecules (answer in #12) are formed when 1 fat molecule is produced? _____
13. What type of reaction makes fat molecules by joining 1 glycerol and 3 fatty acids and removing
water?____________________________
14. A wide variety of fats are formed by different combinations of fatty acid molecules. What part always
remains unchanged in all fats? __________________________________
Part C: Models of Proteins
Part 1: Amino Acids, Building Blocks of Proteins 
Proteins are complex molecules made up of smaller molecules called amino acids. Examine the structural
formulas of the four representative amino acids in Figure 4 and answer questions 1-3.
Figure 4:
Valine
Amino Group
Glycine
Carboxyl Group
“R” or side group
Hydrogen Atom
Central
Carbon
1. Name the four elements present in these amino acids.
a. _____________________________
c. _______________________________
b. _____________________________
d. _______________________________
2. What 5 pieces do all amino acids contain?
a. __________________________ c. _________________________ e. _____________________
b. ________________________
d _________________________
3. If they all contain the same 5 pieces, how do amino acids differ? ________________________________
_______________________________________________________________________________________
Use the structural diagram of the amino acid, Alanine, to answer the following questions.
4. Draw a star around the central carbon.
b. Draw a circle around the carboxyl group.
c. Draw a rectangle around the amino group.
d. Draw a triangle around the “H” atom.
e. Draw an “X” through the “R” or side group.
5a. Do carbohydrates have carboxyl groups? ______
b. Do carbohydrates have amino groups? ______
6. Is there a definite ratio of hydrogen to oxygen atoms in all amino acids? _______________
Part 2: Combining Amino Acids to Form Proteins 
Start with an –OH and –H grup attached to each individual amino acid.
DIRECTIONS: Attempt to join the amino acids using your paper models.
7. Can the amino acid models easily join to form a protein? ______
DIRECTIONS: Join the 4 amino acids in the following order…valine – threonine – alanine – glycine.
Remove as many –OH and –H groups as needed from the amino acids and join these pieces together.
8. What molecule is formed when the –OH’s and –H’s are joined? ______________
9. When 4 amino acids join together, how many molecules of water form? ____________________
10. What polymer or macromolecule is formed when several amino acids join together? ________________
11. There are thousands of different proteins in living organisms. What makes each protein different is the
order, number, kind, and arrangement in space of the amino acids joined.
Using the 4 amino acids you have in front of you, construct 2 different proteins from the one you
already made. List the order of the amino acids.
a. _____________________________________________________________________________________
b. _____________________________________________________________________________________