Functional Groups

Hydrocarbons consist of carbon atoms attached to hydrogen atoms. They are very stable and form the backbone of organic compounds. Functional groups are often covalently bonded to the hydrocarbons and are very important in determining the chemical behavior of the molecule they are attached to.

1. Build and diagram a hydroxyl group

2. Hydroxyl groups are found in sugars and alcohols. One biologically important alcohol is glycerol. It is an important building block of lipids. Build and diagram a glycerol molecule

3. Carbonyl group. A carbonyl group consists of a carbon atom double bonded to an oxygen atom. Carbonyl groups form either ketones or aldehydes depending on where they attach to the carbon chain. Build and diagram a carbonyl group. Carbonyl groups are often found in sugars

4. Build and diagram a ketone.

5. Build and diagram an aldehyde.

6. Explain the difference between an aldehyde and a ketone.

7. Acetone is a ketone. It contains 3 carbon atoms, 6 hydrogen atoms, and 1 oxygen atom. Using this information build and diagram an acetone molecule.

8. A sulfhydyl consists of a sulfur bonded to a hydrogen. Build and diagram a sulfhydryl.

9. A carboxyl group consists of a carbon atom bonded to a hydroxy group and double bonded to an oxygen. It is also called a carboxylic acid group. Build and diagram a carboxylic acid group.

9. An amino group consists of a nitrogen atom bonded to two hydrogen atoms. Build and diagram an amino group.

9. An amino acid contains an amino group on one end and a carboxyl group on the other end. A carbon atom is located between the two functional groups. A side chain (R group) is attached to the central carbon. Amino acids differ from one another in the composition of the side chain. There are 20 amino acids in humans. Join with another group. One group should build alanine (see board). The other group should build glycine. Diagram both of these molecules below. Draw a circle around the amino group and a square around the carboxyl group in each. Draw a triangle around the atoms that will be lost from each one during a dehydration synthesis reaction.

9. Using your models remove the atoms you have placed a triangle around. Attach the two models together as would happen in a dehydration synthesis reaction. This new bond is called a peptide bond. The two attached amino acids are a dipeptide. Long chains are polypeptides. Polypeptides form proteins. Diagram the dipeptide you have created below. What molecule did you remove to make the dehydration synthesis reaction possible?

9. Separate the two amino acids by returning the water (H and OH) to the dipeptide you built above. What is this reaction called. Diagram the reaction.