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SBI4U: Biology, Grade 12, University Preparation

Unit 1: Biochemistry

Activity 3: Molecules and Movement

Building Models

Purpose: In this laboratory you will build some simple organic and inorganic molecules.

Materials: Toothpicks

Marshmallows – small ones of various colours

– colours for H, C, O, N

Procedure:

1. The toothpicks are used to hold the marshmallows together. They will be your covalent bonds

2. The marshmallows will be the atoms. You will need several colours and lots of carbon and hydrogen molecules in particular. The colours you have the most of should be allotted for hydrogen and then carbon. Construct your molecules so that the atoms are as far apart as possible. Generally, atoms are spaced far apart in molecules; however the position can be influenced by other factors (such as the position of the electrons). We will not consider these factors in this lab.

3. Create a molecule of O2 gas. Put two oxygen marshmallows with two toothpicks between them. This is O=O double bond.

4. Create a molecule of CO2 by putting a C in the middle of two O atoms. There should be a double bond between each C and O, creating O=C=O.

5. Now create water, H2O. There are only single bonds between the atoms.

6. Assemble C with 4 H to build methane, CH4. Carbon is the central atom.

7. Now remove an H from methane and add a hydroxyl (OH) group to it. You have made methanol

8. Remove 2H from methanol and make the alcohol into a carboxyl group by adding O=. Now you have built methanoic acid.

9. Remove the last H and add a – CH3 to the molecule. You have built ethanoic acid. Keep this molecule aside

10. Now build another hydrocarbon chain, this time using 3 C atoms attached together by a single bond and several Hs. Use as many H atoms so that each C has 4 bonds in total. You have now built propane.

11. Add a hydroxyl group to the one end of the propane by removing a H atom. Your molecule is propanol.

12. Connect propanol with ethanoic acid – at the functional groups. Remove an molecule of H2O. You have just made an ester called propyl ethanoate.

13. Now build 2 carboxyl groups and 2 amino groups separately.

14. Use one amino group, one carboxyl group and a C atom to build an amino acid

as seen below:

- A carboxyl group

- An amino group

· A hydrogen

· A varying R group

R Groups - There are 20 different R groups which differentiate the 20 amino acids. Of these 20, 8 are essential because they cannot be synthesized from simpler compounds.

15. For the R group of this amino acid, use an H atom. You have built glycine

16. Now build another amino acid with the other carboxyl group and amino group.

17. Make the R group as –CH3. You have now built your second amino acid. What is the name of this amino acid?

18. Connect the two amino acids at the carboxyl group of one with the amino group of the other. What type of linkage is this and what is the name of the reaction?

19. You may take these structures apart and reuse them.

20. Now build a linear structure of glucose. Number the C atoms making the end with the aldehyde as C #1. Remove a H atom from C #1and connect it to C # 5 of the chain by removing a H atom from C #5. You have now made the ring structure of glucose.

21. Now create another molecule of glucose.

22. Connect the two molecules of glucose together by removing H2O. Use C # 1 of one glucose and C#5 of the second glucose. What molecule have you now made? What kind of linkage is this and what is the name of reaction.

Observations: Complete the data sheet provided

THIS IS THE HMWK:

Discussion: Answer the questions provided in the assignment section.

After finishing the lab activity, you will complete the data sheet as the Observation section and answer the following questions.

Discussion Questions:

1. Which molecules were organic?  How did you know?

2. How did you know how many bonds to make for each atom?  Explain

3. Give the complete reaction, using structural formulas, for propanol reacting with ethanoic acid.  Draw the entire reaction including the products and give the type of reaction.

4. Give the complete reaction, using structural formulas, for the two amino acids you built and put together. Draw the entire reaction including the products. What type of linkage is this and what is the name of the reaction?

5. Give the complete reaction, using structural formulas, for the two glucose molecules you built and put together.  Draw the entire reaction including the products.  What type of linkage is this and what is the name of the reaction?