MODELING MACROMOLECULES Name __________________________________ Per _____

Work in teams of FOUR (4) Group Members __________________________________

________________________________________________

CARBOHYDRATES

A. Monosaccharides

1. Using the parts shown above, each team member should construct a chain of SIX (6) CARBON atoms as shown in Figure 2. Use TWO (2) bonds to attach an OXYGEN atom to the first carbon, or C1. This represents a DOUBLE bond.

2. Attach ONE (1) HYDROGEN atom to EACH of the five O atoms. These are called –OH, or hydroxide, groups and they tend to act together, as a unit, in many reactions. Attach the –OH groups to the carbon chain in the positions indicated in Figure 2.

3. Now attach SEVEN (7) more H atoms to the carbon chain in the positions shown in Figure 2. The model each team member has completed represents an open chain glucose molecule. Show your model to the instructor for verification of correctness. Instructor initial _______

4. Crystalline glucose occurs in this form. However, glucose in biological systems usually occurs in a RING form. To demonstrate the ring form, twist the carbon chain to bring together C1 and C5 as shown in Figure 3.

5. When the ends of the molecule are brought together, the double-bonded O (attached to C1) reacts with the –OH group (attached to C5). Compare Figure 3 and Figure 4. Rearrange the atoms to complete the glucose ring structure in Figure 4. Instructor initial _______

CARBOHYDRATES (cont.)

6. What is the final formula for the glucose molecule? C___ H___ O___

7. Have ONE (1) member of the group restructure a glucose molecule into a fructose molecule, using Figure 5 as a guide. NO ATOMS need to be removed, only rearranged.

8. What is the final formula for the fructose molecule? C___ H___ O___

9. Molecules with the SAME formula but DIFFER in structure or shape are called isomers. Are glucose and fructose isomers? Use evidence from your model to support your answer. ____________________________________________________________ __________________________________________________________________________________________

B. Disaccharides

1. Bring together ONE glucose and ONE fructose molecule, as shown in Figure 6. Remove the entire –OH group from the C1 atom of glucose and the H atom (from the –OH group) of the C2 atom of fructose.

2. What molecule do these removed atoms form? ____________________

3. The disaccharide molecule that has been formed is sucrose, also known as table sugar. What is the final formula for the sucrose molecule? C___ H___ O___ (Hint: C12H24O12 – H2O)

4. Repeat steps 1 and 2, but this time use the remaining TWO (2) glucose molecules. Use Figure 7 as a guide.

5. The molecule that has been formed is the disaccharide maltose. What is the final formula for the maltose molecule? C___ H___ O___

6. Are sucrose and maltose isomers? Use evidence from your model to support your answer. ____________________________ ___________________________________

7. Using the disaccharide(s), describe how you could model a polysaccharide, such as starch (in plants) and glycogen (in animals). ________________________________________________________________________

8. Disassemble ALL parts and return them to the container. Look on the floor for any spare parts. Thanks!

MODELING MACROMOLECULES Name __________________________________ Per _____

Work in teams of FOUR (4) Group Members __________________________________

________________________________________________

LIPIDS

A. Fatty Acids

1. Using the parts shown above (same parts as carbohydrates), build ONE fatty acid per team as follows: (a) Use TWO (2) bonds to attach an O atom to a C atom. (b) Attach an –OH, or hydroxide, group to the C atom. This is called the carboxyl group, represented –COOH, and, like –OH, it tends to act chemically as a unit.

2. Attach a chain of SEVENTEEN (17) C atoms to the –COOH group.

3. Fill in ALL available spaces on the carbon chain with H atoms. You now have a model of a fatty acid. This one is called stearic acid, a major component of shea and cocoa butters. It is also used in the manufacture of soaps & shampoos. Instructor initial _______

4. Fatty acids are considered to be SATURATED if all available bonds in the carbon chain are filled with H atoms. Is stearic acid a saturated fat? ________

5. Counting the C atom of the –COOH group as #1 (C1), count along the molecule to locate C9 & C10. Remove ONE (1) H atom from each C9 & C10.

6. Connect C9 and C10 together with a DOUBLE bond. The molecule is now oleic acid, which composes the majority of olive oil. It also makes up other oils such as pecan, canola, peanut, and sunflower. Oleic acid is the most abundant fatty acid in human adipose (fat) tissue. Instructor initial _______

7. Is oleic acid a saturated fat? _______

8. Fatty acids which have one or more double bonds in their carbon chains are called UNSATURATED fats. Is oleic acid an unsaturated fat? Use evidence from your model to support your answer. ____________________ __________________________________________________________________________________________

9. Remove ONE (1) H atom each from C 12 and C13. Connect these C atoms with a double bond.

10. Repeat step 9 for C15 and C16.

11. The molecule is now linolenic acid, a colorless to yellowish oil obtained from the dried, ripened seeds of the flax plant. Instructor initial _______

12. Is linolenic acid a saturated or unsaturated fat? _____________________________________

(Disassemble the fatty acid model to get ready for Part B)

LIPIDS (cont.)

B. Triglycerides: Fats & Oils

1. Have THREE (3) team members EACH construct molecules of butyric acid as shown in Figure 1. The 4th team member builds a glycerol molecule as shown in Figure 2.

2. Is butyric acid a saturated or unsaturated fat? _______________________________

3. Attach the THREE (3) molecules of butyric acid to the glycerol by “reacting” the –COOH groups of the acids with the –OH groups of the glycerol as indicated in Figure 3. You have now made a triglyceride molecule. Instructor initial _______

4. THREE molecules of __________ are removed or produced in this reaction.

5. Where do you think the name triglyceride comes from? ________________________ _______________________________________________________________________

6. Triglycerides are common lipids found in animal fats and plant oils. This model is called tributyrate. The name comes from the Latin word for butter, butyrum, and, as its name indicates, is found in butter, as well as goat and buffalo milk and parmesan cheese.

7. Both carbohydrates and lipids are SIMILAR in that they are both composed of carbon, hydrogen and oxygen. How are they DIFFERENT?

__________________________________________________________________

8. The physical properties of a triglyceride are influenced by its fatty acids. Saturated triglycerides tend to be solid / liquid (circle one) at normal temperatures and are called fats / oils (circle one). For example, animals which operate at elevated temperatures (such as humans) tend to store lipids as FATS.

9. Unsaturated triglycerides tend to be solid / liquid (circle one) at normal temperatures and are called fats / oils (circle one). For example, plants which operate at lower temperatures tend to store lipids as OILS.

10. Disassemble ALL parts and return them to the container. Look on the floor for any spare parts. Thanks!

MODELING MACROMOLECULES Name __________________________________ Per _____

Work in teams of FOUR (4) Group Members __________________________________

________________________________________________

PROTEINS

A. Amino Acids

1. Using the parts shown above, EACH team member should use a double bond to attach an O atom to a C atom. Also attach an –OH group to the C atom. You should recognize this group. What is its name and how is it represented chemically? (Hint: look back at lipids) _________________________________________________

2. Now attach THREE (3) H atoms to a NITROGEN atom. This is a model of the ammonia molecule. Ammonia is often used in window & glass cleaner.

3. Remove one of the H atoms from ammonia. The group of atoms left, –NH2, is called the amino group.

4. Where does the name amino acid come from? (Hint: two group names) _____________________________ __________________________________________________________________________________________

5. Bond the –COOH and –NH2 groups to ONE C atom as shown in Figure 1 (ignore the R in the figure for now).

6. Attach ONE H atom to the central C atom. All amino acids share this basic structure. They DIFFER in the atom or groups of atoms which attach to the open carbon bond, represented by R in Figure 1.

7. To make a complete amino acid, have EACH member choose an amino acid from Figures 1, 2, 3 or 4. If Figure 1 is chosen, that amino acid is glycine. Each team member now attaches more C, H &/or O atoms to their central C atom, depending on which amino acid they are building.

8. Which amino acid did YOU create? _____________________________ Instructor initial _______

PROTEINS (cont.)

B. Dipeptides, Polypeptides and Peptide Bond

1. Using the amino acid models from Part A, bring together the carboxyl end (–COOH) of one amino acid and the amino end (–NH2) of another, as shown in Figure 5 below.

2. Join the two amino acids by removing the –OH group from one and H atom from the other. Then bond the C atom to N atom. What molecule did you remove? ___________________________

3. The resulting model is a peptide, specifically a dipeptide: TWO amino acids held together by a peptide (C-N) bond. Instructor initial _______

4. Notice that the dipeptide still has a carboxyl end and an amino end. This means that it can still react with additional amino acids to produce a peptide chain. Attach the remaining amino acids made by your team to the dipeptide by removing a water molecule for each amino acid attached (step 2 again).

5. When all four amino acids are bonded, you now have a polypeptide. Instructor initial _______

6. Proteins are formed from even longer chains that are branched, or twisted and folded. Using the polypeptides you made, describe how you could model a protein. ____________________________________ __________________________________________________________________________________________

7. How does a polypeptide differ from a polysaccharide? ___________________________________________ __________________________________________________________________________________________

8. Disassemble ALL parts and return them to the container. Look on the floor for any spare parts. Thanks!

FOLLOW-UP

a. What did you like best about this modeling activity?

b. What did you like least about this activity? Don’t whine—suggest improvements.